The current work introduces highly dispersed Pt and PtSn catalysts supported on La2O2CO3 nanorods prepared via ultrasonic impregnation, which are used as probe catalysts for the liquid-phase crotonaldehyde hydrogenation. The physicochemical properties of the catalysts are assessed by means of various techniques, including XRD, TEM, XPS, H2-TPD, in situ CO-DRIFT and X-ray adsorption fine structure (XAS). A close combination of catalyst surface experiments and the reactive performances reveals that the distinct reactive performance of the Pt and PtSn catalysts is tentatively attributed to the composition-dependent architecture of Pt–lanthanum interfaces and bimetallic particles while excluding the particle size effect. Catalytic activity tests demonstrate that incorporation of Sn into Pt catalyst brings great significance to the selective hydrogenation of carbonyl groups as it results into the structure evolution of bimetallic particles. An optimization of Sn loading and reaction conditions achieves a 5-fold and 7-fold improvement in the selectivity and yield to crotyl alcohol over the parent Pt catalyst. Lastly, it is found from the catalyst reusability study that metal particles of PtSn catalysts suffers easily from particle migration and growth compared to the Pt catalyst, most likely resulting from a weaker metal–support interaction.

•A novel mesoporous ZrO2/SO42− has been prepared via a facile one-pot EISA strategy.•The M-ZrO2/SO42− exhibited excellent textural and acidic properties.•The introduced S species were homogeneously dispersed in mesoporous skeleton.•The M-ZrO2/SO42− exhibited excellent catalytic performance and reusability.In this paper, a novel mesoporous sulfated zirconium (M-ZrO2/SO42−) has been gotten by one-pot evaporation-induced self-assembly (one-pot EISA) strategy. The SXRD, N2-physisorption and TEM characterization techniques indicated that M-ZrO2/SO42− possessed distinct mesostructure with big specific surface area (133.5 m2 g−1), large pore volume (0.18 cm3 g−1) and narrow pore size distribution (4.90 nm). Moreover, the existing states and the influence in mesostructure of introduced S species were detailedly investigated by the XRD, N2-physisorption, TEM, TG-DSC, FT-IR and XPS techniques and the results showed that the S species, which existed as the type of SO42−, improved the textural properties of prepared materials. In addition, the NH3-TPD and IR spectra of adsorbed pyridine indicated the existence of strong Brønsted and Lewis acid sites in M-ZrO2/SO42− even evacuated at 400 °C. Furthermore, the M-ZrO2/SO42− was used as a promise solid acid catalyst and displayed excellent catalytic performance and reusability in Friedel-Crafts benzylation reaction.Download high-res image (220KB)Download full-size image

Two kinds of nano-CeO2-supported low loading Ru catalysts were prepared by ultrasonic-assisted incipient wetness impregnation method and their applications in catalytic wet air oxidation (CWAO) of butyric acid (BA) were investigated. Both of the catalysts were characterized by XRD, XPS, TEM, N2 adsorption–desorption, Raman and H2-TPR. According to the characterization results, compared to Ru/CeO2 catalyst, the active component was well dispersed on the support and the particle sizes were smaller for the Ru/CeO2-A catalyst which was added to some absolute ethanol in the process of preparation. Meanwhile, Ru/CeO2-A catalysts possessed a high active surface area and had a higher Ce3+ and oxygen vacancy content due to the strong interaction between Ru species and CeO2. Therefore, the Ru/CeO2-A catalyst presented higher catalytic activity and the chemical oxygen demand (COD) removal can increase up to 64.05% after 2 h. It had excellent stability and can be reused many times without obvious loss of activity.

In this paper, a sequence of ordered mesoporous chromium–zirconium oxophosphate (M–Cr–ZrPO) composites with controllable chromium contents (0–15 mol%) were projected and successfully synthesized through a modified one-pot evaporation-induced self-assembly method. Characterized by N2 adsorption–desorption isotherms and TEM techniques, the resultant M–Cr–ZrPO composites owned ordered mesoporous structure and the textural properties [specific surface areas (160–210 m2 g−1), pore volumes (0.25–0.28 cm3 g−1) and pore sizes (5.6–6.6 nm)] of materials were improved by the introduced chromium species. In addition, the dispersion, existing states and contents of introduced chromium species in the materials were researched in detail by elemental mapping images, XRD, UV–vis, FT-IR, XPS and H2-TPR techniques. All the characterizations implied that the chromium oxides were introduced as expected and homogeneously dispersed in the skeleton of mesoporous materials. Owing to the outstanding structural properties and chromium species with homogeneous dispersion, the M–Cr–ZrPO materials exhibited superior catalytic activity for liquid phase oxidation of benzyl alcohol and ethylbenzene.

The relationship between the structure and Mo species in mesoporous molybdena–alumina catalysts and their catalytic performance for isobutane dehydrogenation has been investigated in detail. Characterization by XRD, HAADF-STEM, EDX, FT-IR, and N2 physisorption illustrated that ordered mesoporous catalysts (OM-Al, MoAl(F), and MoAl(C)) possessed an amorphous alumina phase and non-ordered mesoporous catalysts (M-Al and MoAl) exhibited a γ-Al2O3 phase. Mo species were highly dispersed over all the catalysts because Mo surface densities were about 1.0 Mo nm−2. Moreover, XPS and ICP-OES showed that Mo species were uniformly distributed over MoAl(F) with the Mo species confined in the ordered mesoporous structure. Higher dehydrogenation stability and a lower coke formation rate, albeit lower catalytic conversion, was obtained over MoAl(F) in comparison with those of MoAl(C) and MoAl on account of its stronger metal–support interaction, as shown by H2-TPR technique. The catalyst with a γ-Al2O3 phase exhibited stronger acidity and higher activity than the corresponding catalyst with an amorphous phase. The acidity of the catalysts was greatly enhanced by the addition of Mo species, according to the NH3-TPD characterization. However, not all the acid sites were active sites for dehydrogenation activity. The moderately and strongly acidic sites and the Mo species, including Mo6+ and lower valence Mo species, probably contributed to the dehydrogenation reactivity. Moreover, deactivation of the catalysts was mainly due to coke formation over the spent catalysts.

Rod-like and particle-like La2O2CO3 and La2O3 were obtained via morphology-preserved thermal transformation of the La(OH)3 precursors. La2O2CO3- and La2O3-supported Pt catalysts were prepared by impregnation method and tested in the liquid-phase crotonaldehyde hydrogenation reaction. The textural and physicochemical properties of the samples were studied by a series of techniques including XRD, TG-DSC, N2 adsorption–desorption, TEM and HRTEM, IR spectrum, H2-TPD, and H2-TPR. Even after 600 °C reduction, Pt particles of about 0.8–2.8 nm interplayed with support surface to form Pt-doped interface, thereby preventing the catalysts from migration and affording a high dispersion of platinum. The specific exposed crystal-facets and surface oxygen species depending on the shape of the support affected the preferential deposition of Pt species and the metal-support interaction. Thus, Pt catalysts performed different physicochemical properties and catalytic performance relying on the morphology and structure of the supports. During the cycle experiment, severe deactivation was observed for NP-supported catalysts with an increased selectivity due to the aggregation and growth of Pt particles. Meantime, the NR-supported catalysts retained relatively high reactivity as a consequence of the crystal-facet confinement of rod-shaped lanthanum supports.

Mesoporous Mn–Zr composite oxides (M–MnZr) with a crystalline wall were designed and achieved by a facile one-pot evaporation-induced self-assembly (EISA) strategy. As proved by XRD, HRTEM and SAED characterization, the wall of the obtained mesoporous materials exhibited a typical tetragonal phase of ZrO2. In addition, the introduced manganese species were homogeneously dispersed in the mesoporous skeleton. N2-physisorption and TEM results showed that all the final materials possessed an obvious mesoporous structure accompanied by a large specific surface area (∼120 m2 g−1), big pore volume (∼0.2 cm3 g−1) and uniform pore size (∼4.9 nm). In addition, the liquid phase oxidation was chosen as the test reaction and the excellent catalytic performance of M–MnZr demonstrated their potential applications in oxidation reactions.

A series of ordered mesoporous transition metal–zirconium oxophosphate composites (M–X–ZrPO, X = Cr, Mn, Fe, Co, Ni, Cu, Zn) were designed and synthesized via a facile and general one-pot evaporation-induced self-assembly (EISA) method. N2-physisorption and TEM characterization showed that all the final materials possessed ordered mesoporous structure accompanied by large specific surface area (170–220 m2 g−1), big pore volume (0.2–0.4 cm3 g−1) and uniform pore size (5.6–7.8 nm). Moreover, the introduced transition metals homogeneously dispersed in the mesoporous skeleton and effectively improved the mesostructure. The catalytic performance of M–X–ZrPO was evaluated in the liquid phase oxidation of ethylbenzene. The introduced transition metals obviously enhanced the catalytic performance of M–ZrPO. M–Mn–ZrPO showed excellent catalytic activity with 91.6% conversion of ethylbenzene and 87.0% selectivity of acetophenone. After five cycles, there was no notable decrease in catalytic activity. Therefore, it was a promising catalyst for the oxidation of ethylbenzene.

•A series of M-ZrPO have been prepared via evaporation induced self-assembly strategy.•Superior fructose conversions and 5-HMF selectivity were achieved with M-ZrPO-0.75.•The M-ZrPO showed excellent structure stability and higher catalytic stability.In this paper, a series of ordered mesoporous zirconium oxophosphate with different P/Zr molar ratios (M-ZrPO-x) were prepared via one-pot evaporation induced self-assembly strategy (EISA). The catalytic performance of M-ZrPO-x for the dehydration reaction of fructose to produce 5-hydroxymethylfurfural (5-HMF) was also studied. With high concentration of Brönsted and Lewis acid sites measured through NH3-TPD and pyridine-IR, M-ZrPO-0.75 performed high catalytic activity (up to 97.4%) and selectivity (79.6%) of 5-HMF under relatively mild conditions. Furthermore, M-ZrPO-0.75 performed excellent catalytic stability. Based on detailed analyses of XRD, SEM, TEM, BET and XRF, the structural, surface and textural properties of M-ZrPO-0.75 after reaction were investigated. Obtained results demonstrated that the mesostructure still retained even after twelve cycles, which may be ascribed to the “ordered” mesoporous properties and high thermal stability. In addition, a lower activation energy was obtained in this M-ZrPO catalytic system using dimethyl sulfoxide as solvent.Graphical abstract

•Catalyst prepared with macroporous Al2O3 showed high HDS selectivity but low activity.•Catalyst with micro- or meso-porous Al2O3 had high HDS activity but low selectivity.•Catalyst with tri-modal porous Al2O3 balanced HDS activity and selectivity.•Co–Mo/Al2O3 with macroporous Al2O3 had low intra-particle diffusion resistance.To improve the selectivity performance of CoMoS catalysts applied to the hydrodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline, a series of CoMoS/Al2O3 catalysts was prepared with alumina of different pore structures, and their HDS performance was evaluated with a real FCC gasoline. This study indicated that CoMoS/Al2O3 catalysts prepared with micro- or meso-porous alumina possessed high HDS activity but low selectivity, whereas macro-porous alumina enhanced the selectivity of CoMoS catalysts. The enhanced HDS selectivity was due to the tuning of the MoS2 slabs and the weakening of the internal diffusion resistance. Based on the above results, the optimal CoMoS/Al2O3 catalyst was prepared with the alumina of the tri-modal pore distribution at approximately 5–8 nm, 15–20 nm, and 90–100 nm. The optimal catalyst displayed a balanced HDS activity and selectivity in contrast to the reference catalyst prepared with K- and P-modified Al2O3.

Mesoporous zirconium phosphotungstate (M-ZrPW), with large specific surface area (~170 m2 g−1), large pore volume (~0.25 cm3 g−1), uniform pore size distribution (~6.5 nm) and tunable W/Zr ratios (0–0.2), was successfully prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. Small-angle X-ray diffraction (SXRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) characterizations showed that these materials had a mesoporous structure even when the W/Zr ratio reached up to 0.2. The tungsten species introduced via this strategy highly were dispersed among the wall of mesoporous framework. More importantly, the tungsten species greatly improved the Brønsted acidic property and catalytic activity in the Friedel–Crafts benzylation reaction. The highest activity was obtained at a W/Zr ratio of 0.2 with the strongest Brønsted acidity. In addition, the influences of various reaction parameters such as reaction time, amount of catalyst and calcination temperature of the catalyst, systematically investigated in this paper. Furthermore, the M-ZrPW showed a higher catalytic activity than H-Beta, H-ZSM5 and ZrPW prepared by the sol–gel method. Meanwhile, M-ZrPW could be reused at least for five cycles in the benzylation reaction without any notable decrease of catalytic activity.

An ordered mesoporous CaO–Al2O3 composite oxide had been designed and prepared via improved evaporation induced self-assemble strategy (EISA). The resultant material was utilized as the support of Ni based catalyst for CO2 reforming of CH4. In order to study the roles of the ordered mesopore structure and basic modifier in promoting the catalytic properties toward the CO2 reforming of CH4 reaction, non-mesoporous CaO–Al2O3 without ordered mesostructure and ordered mesoporous Al2O3 without basic modifier were also synthesized, respectively. It was found that both the ordered mesostructure and CaO basic modifier showed significant effects in promoting catalytic activity, stability and suppressing the carbon deposition during their 100 h long term stability tests. Compared with traditional supported catalysts, the confinement effect of the mesoporous catalysts could effectively inhibit the thermal sintering of the Ni particles. Furthermore, the sorts of coke species over the spent catalysts and the mechanism of catalyst deactivation were also carefully investigated. Therefore, the present ordered mesoporous CaO–Al2O3 composite oxide will be a potential carrier for Ni-based catalysts for CO2 reforming of CH4 and even other reactions.

•Mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O oxides synthesized via one-pot EISA strategy.•The obtained materials investigated as the catalysts for dry reforming.•“Confinement effect” of the mesostructure inhibited severe sintering of the Ni nanoparticles.•Rare earth modifiers improved catalytic activities and reduced the coke.•Rare earth elements influenced the sorts of carbon species over the catalysts.A series of rare earth elements functionalized mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides were originally designed and facilely synthesized via one-pot evaporation induced self-assembly (EISA) strategy. These mesoporous materials with outstanding thermal stability were investigated as the catalysts for the CO2 reforming of CH4, performing excellent catalytic activities and long-term catalytic stabilities. The “confinement effect” of the mesoporous framework matrixes contributed to stabilizing the Ni nanoparticles during the process of reaction; therefore, the serious thermal sintering of the Ni nanoparticles under severe reduction and reaction conditions was suppressed to some degree, accounting for the long catalytic stability of these mesoporous catalysts. The modification of the rare earth elements (Ce, La, Sm, Pr) played crucial roles in promoting the catalytic activities and reducing the carbon deposition. Besides, the presence of the rare earth elements also significantly influenced the distribution of the carbon species deposited over the spent catalysts. Hereby, these mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides promised a group of novel and stable catalyst candidates for carbon dioxide reforming of methane.

A series of WO3 supported on ordered mesoporous zirconium oxophosphate (X wt% WO3/M-ZrPO) solid acid catalysts with a WO3 loading from 5 to 30 wt% were successfully synthesized, and their structure properties were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2-physisorption, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, H2 temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The catalytic performance of X wt% WO3/M-ZrPO in liquid phase benzylation of anisole was studied and the relation between activity and states of tungsten species was investigated detailedly. The maximum catalytic activity was reached at a 20 wt% WO3 loading, which possessed highly dispersed WO3 species and the strongest Brønsted acidity. Meanwhile, the well dispersed WO3 species strongly interacted with M-ZrPO, therefore, both sintering and leaching of WO3 species were effectively restrained. Moreover, compared with the traditional zirconium phosphate synthesized from the sol–gel method (ZrPsol–gel), the M-ZrPO with an abundant ordered mesostructure was propitious for improving the dispersion of WO3 species and catalytic performance. In addition, the 20 wt% WO3/M-ZrPO showed a markedly higher catalytic activity than H-ZSM5, H-Beta and 20 wt% WO3/ZrPsol–gel. Furthermore, the catalyst showed no discernible loss in activity or selectivity after five cycles.

•A series of ordered M-Cu-ZrPO were synthesized via a facile one-pot EISA method.•The M-Cu-ZrPO had excellent textural properties and thermal stability.•The copper contents could be controlled in a wide range.•The introduced copper species were homogeneously dispersed in mesoporous skeleton.•The M-Cu-ZrPO showed excellent catalytic performance in oxidation reaction.A series of mesoporous Cu-ZrPO (M-Cu-ZrPO) materials with high specific surface area (∼200 m2 g−1), large pore volume (∼0.4 cm3 g−1), uniform pore size (∼7.8 nm) and various copper contents in a wide range (0–40%) were successfully synthesized via a facile one-pot evaporation induced self-assembly (EISA) strategy. Different characterization techniques, XRD, N2-physisorption, TEM, TG-DSC, UV–vis spectra and H2-TPR were employed to investigate the mesoporous structure and copper states. The ordered mesostructure was improved with the introduction of copper species and could be successfully maintained even at a copper content up to 30%, in which the copper species were highly dispersed in the skeleton of mesostructure. Additionally, M-Cu-ZrPO exhibited excellent thermal stability and the ordered mesostructure could be successfully preserved even after treating at 700 °C. Moreover, M-Cu-ZrPO was employed as catalyst for liquid phase oxidation of ethylbenzene. On account of the advantageous mesoporous structure and highly dispersed copper species, the catalytic performance of M-Cu-ZrPO was gradually improved with the increasing of copper contents and achieved the maximum at 30% copper content with 91.2% conversion of ethylbenzene and 87.0% selectivity of acetophenone. In addition, M-Cu-ZrPO showed excellent stability and reusability even after five cycles.A series of ordered mesoporous Cu-ZrPO (M-Cu-ZrPO) materials with various copper contents, excellent textural properties and thermal stability were successfully synthesized via a facile one-pot EISA strategy. In addition, the M-Cu-ZrPO showed excellent catalytic performance in liquid phase oxidation of ethylbenzene.

•The cylindrical MOF-5-BPO crystals were firstly synthesized by BPO.•The pore volumes of MOF-5-BPO were 0.84–1.07 cm3 g−1, higher than that of MOF-5-H2O2.•The concentration of BPO was critical for the pore texture of MOF-5-BPO.•MOF-5-BPO could store 1.24 wt% H2 at 77 K and 100 KPa.In this study, for the first time, the uniform cylindrical MOF-5-BPO (Zn4O(BDC)3(H2O)·0.5ZnO, BDC = 1,4-benzenedicarboxylate, BPO = benzoyl peroxide) crystals with large Brunauer–Emmett–Teller (BET) surface area (3210.2 m2 g−1) was successfully synthesized by room temperature synthesis in the presence of BPO using zinc nitrate hexahydrate (Zn(NO3)2·6H2O) as the zinc source. The pore volumes of MOF-5-BPO materials prepared with different concentrations of BPO were 0.84–1.07 cm3 g−1, higher than that of MOF-5-NP (0.68 cm3 g−1, Zn4O(BDC)3(H2O)3·2ZnO) and MOF-5-H2O2 (0.84 cm3 g−1, Zn4O(BDC)3(H2O)2·2ZnO, H2O2 = hydrogen peroxide). The addition of the peroxides created new pores, which possessed the same diameters as the existing ones, thus increased the pore volume of the product. The concentration of BPO was critical for the pore texture of MOF-5-BPO. Moreover, MOF-5-BPO could store 1.24 wt% hydrogen at 77 K and 100 kPa. Thus, this study points out some information for one to realize the influence of the peroxides over MOF-5 structure and promises the potentiality of large-scale production of MOF-5 structure with large surface area.

A series of mesoporous zirconium oxophosphate (M-ZrPO) with different P/Zr molar ratios (0–1.25) has been prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. After removing the structure-directing agents, the M-ZrPO with large specific surface area (160 m2 g−1), big pore volume (0.26 cm3 g−1) and narrow pore size distribution (5.64 nm) has been obtained. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that these materials had ordered mesoporous structure. With the increase of P/Zr, the textural properties of M-ZrPO could be improved. Moreover, the ordered mesostructure could be maintained even when treated at 800 °C, indicating the M-ZrPO had attractive thermal stability. NH3-TPD and pyridine-IR analyses showed the presence of abundant Brönsted and Lewis acid sites in the material. The M-ZrPO has been used successfully as solid acid catalyst and showed excellent performance in the ketalization reaction.

Hybrid colloids (HCs) have shown distinct optical, electric, and optoelectronic properties from the components, mainly because of electronic interplay between the components. Here we investigate different charge transfer behaviors of dumbbell-structured CdSe-seeded CdS nanorods with metallic and semiconducting tip materials respectively studied by UV-vis and photoluminescence (PL) spectra, i.e. gold-tipped CdSe-seeded CdS nanorods and palladium sulfide-tipped CdSe-seeded CdS nanorods. They have shown remarkably different optical properties due to different charge transfer processes, i.e. one is only excited electrons transferred from the CdS shell to gold tips while the other is holes as well as electrons injected from the CdS shell into the palladium sulfide tips. The effect of the charge transfer on Rhodamine B (RhB) photodegradation is further investigated. Very interestingly, totally opposite effects were found, that is gold tips enhanced photodegradation rate while palladium sulfide tips vastly reduced photodegradation. Those phenomena are well explained by our proposed mechanism for the charge transfer. This study enables better design of HCs for improved photocatalysis and better photovoltaics.

•The mesoporous Cr2O3/Al2O3 catalysts were successfully synthesized using MIL-101.•The inorganic aluminium sources had significant effects on structure of catalysts.•The surface Cr species existed mainly as Cr6+ and Cr3+ over the catalysts.•Cr2O3/Al2O3–N exhibited higher selectivity and stability than the reference catalyst.•Cr2O3/Al2O3–N exhibited high regenerative ability in isobutane dehydrogenation.The mesoporous chromia/alumina (Cr2O3/Al2O3) catalysts were successfully synthesized using a porous metal–organic framework MIL-101 (Cr3F(H2O)2O(BDC)3·nH2O, BDC = 1,4-benzenedicarboxylate) as a molecular host and chromium precursor, inorganic aluminium salt as the aluminium precursor. The aluminium sources had the significant effects on the structure of the products. The formation of α-Cr2O3 phase was observed in the mesoporous catalyst (Cr2O3/Al2O3–C) prepared by AlCl3·6H2O, whereas additional chromia alumina solid solution CrxAl2−xO3 phase was produced in the catalyst (Cr2O3/Al2O3–N) using Al(NO3)3·9H2O as the aluminium precursor. The surface Cr species existed in the Cr6+ and Cr3+ state over the mesoporous catalysts. The Cr species had a strong interaction with the alumina support. Preliminary catalytic studies showed that the Cr2O3/Al2O3–N catalyst exhibited much higher isobutene selectivity and higher stability than the reference catalyst in the isobutane dehydrogenation. The maintainable dehydrogenation activity during the five dehydrogenation-regeneration cycles indicated high regenerative ability of the catalyst Cr2O3/Al2O3–N. Consequently, this study represents a feasible way toward the facile synthesis of the mesoporous chromia/alumina catalyst. Moreover, this work proposes a novel application of metal–organic framework.The mesoporous chromia/alumina (Cr2O3/Al2O3) catalysts were successfully synthesized using a porous metal-organic framework MIL-101 as a molecular host and chromium precursor, inorganic aluminium salt as the aluminium precursor.

•Ordered mesoporous MgO–Al2O3 with various Mg content prepared by EISA method.•The obtained materials used as carriers of Ni based catalysts for dry reforming.•The “confinement effect” of the mesopore inhibited the growth of Ni nanoparticles.•The modified MgO intensified the chemisorption and activation of CO2.•Properties of the coke over the spent catalysts were investigated.A series of ordered mesoporous MgO–Al2O3 composite oxides with various Mg containing were facilely synthesized via one-pot evaporation induced self-assembly strategy. These materials with advantageous structural properties and superior thermal stabilities were used as the supports of Ni based catalysts for CO2 reforming of CH4. These mesoporous catalysts behaved both high catalytic activities and long term stabilities toward this reaction. The effects of the mesopore structure and MgO basic modifier on catalytic performances were carefully studied. Specifically, their mesoporous frameworks could accommodate the gaseous reactants with more “accessible” Ni active centers; the “confinement effect” of the mesopores would effectively suppress the thermal sintering of the Ni nanoparticles; the modified MgO basic sites would enhance the chemisorption and activation of CO2. Consequently, the catalytic activities and stabilities of these catalysts were greatly promoted. Therefore, the present materials were considered as promising catalyst supports for CO2 reforming of CH4.

•Cd modified TS-1 were used as catalysts for butadiene epoxidation.•The addition of Cd significantly promoted vinyloxirane yield and H2O2 utilization.•Quantum chemical calculations were used to explore detailed Cd roles in TS-1.•Five-membered cyclic intermediate formation was facilitated for Cd modification.•Active O eletrophilicity in H2O2 was promoted for Cd modification.A series of Cd modified titanium silicalite 1 catalysts with different Cd content (xCd-TS-1, x = 1–15) were successfully prepared by ultrasound impregnation. Epoxidation of butadiene over these catalysts were investigated using hydrogen peroxide as oxidant, which indicated that Cd greatly improve the catalytic performance of TS-1 and the selectivity of epoxide. Various characterization methods including quantum chemical calculation were employed to explore the specific roles of Cd in promoting TS-1 catalytic activity. Theoretical calculation consistently suggested TiO bond were weakened owing to the introduction of Cd, which resulted in the structure of Cd-TS-1 becoming more relaxant. As a consequence, it is favorable to methanol solvent and H2O2 interacting with the Ti active site to form five-member transition state during reaction. It was observed that catalysts modified with 1–5 wt% Cd presented both high catalytic activity and good reusability. The highest yield of 0.63 mol/L of vinyloxirane (VO) was obtained, while turnover number (TON, determined as the molar VO obtained per molar Ti atom) could reach to 1466.Epoxidation of butadiene to vinyloxirane were carried out over Cd modified TS-1 catalysts. The additive of Cd provided more chances for CH3OH and H2O2 to approach the Ti active sites and hence facilitated the formation of five-membered cyclic intermediate. Moreover, O of H2O2 close to Ti in five-membered intermediate was activated with promoted eletrophilicity by Cd modification.

Ordered mesoporous tricompound NiO–CaO–Al2O3 composite oxides with various Ca content were first designed and facilely synthesized via a one-pot, evaporation-induced, self-assembly (EISA) strategy. The obtained mesoporous materials with advantageous textural properties and superior thermal stabilities were investigated as the catalysts for the carbon dioxide reforming of methane reaction. These mesoporous catalysts entirely showed high catalytic activities as well as long catalytic stabilities toward this reaction. The improved catalytic activities were suggested to be closely associated with the advantageous structural properties, such as large specific surface areas; big pore volumes; and uniform pore sizes, which could provide sufficient “accessible” active centers for the gaseous reactants. In addition, the “confinement effect” of the mesoporous matrixes contributed to stabilizing the Ni active sites during the processes of reduction and reaction, accounting for the long lifetime stabilities of these mesoporous catalysts. The modification of Ca played dual roles in promoting the catalytic activities and suppressing the carbon deposition by enhancing the chemisorption of the CO2. Generally, the ordered mesoporous NiO–CaO–Al2O3 composite oxides could be considered as promising catalysts for the carbon dioxide reforming of methane reaction.Keywords: carbon dioxide reforming; confinement effect; methane; NiO−CaO−Al2O3; one-pot synthesis; ordered mesopores;

Ordered mesoporous alumina facilely synthesized via improved evaporation-induced self-assembly (EISA) strategy was provided with large specific surface area, big pore volume, uniform pore size and excellent thermal stability. The obtained mesoporous material was used as the carrier of the Ni based catalysts for carbon dioxide reforming of methane. These mesoporous catalysts performed high catalytic activity and long stability. Typically, the catalytic conversions of the CH4 and CO2 were greatly close to the equilibrium conversion and no deactivation was observed during the 100 h long lifetime test. The advantageous structural properties of ordered mesoporous alumina contributed to high dispersion of the Ni particles among the mesoporous framework, which further accounted for the good catalytic activity due to more “accessible” Ni active sites for the reactants. The “confinement effect” of the mesopores could effectively prevent the thermal sintering of the Ni nanoparticles to some extent, committed to its long-term catalytic stability. Besides, the mesoporous catalysts possessed enhanced ability to withstand coke, although not any modifiers had been added. Properties of the coke over the mesoporous catalyst were also carefully investigated. Therefore, the ordered mesoporous alumina was a promising catalyst support for the carbon dioxide reforming with methane.Highlights► Ordered mesoporous alumina was investigated as carrier of Ni based catalysts for dry reforming. ► These mesoporous catalysts performed excellent catalytic activities and long-term stabilities. ► The “confinement effect” of the mesostructure contributed to the distinguished catalytic performances. ► These mesoporous catalysts possessed enhanced capability to tolerate coke. ► Characteristics of the coke over the mesoporous catalysts were carefully investigated.

A series of mesoporous nanocrystalline ceria–zirconia solid solutions with different Ce/Zr ratios were facilely synthesized via improved evaporation induced self-assembly strategy. The obtained materials with advantageous structural properties and excellent thermal stabilities were characterized by various techniques and investigated as the supports of the Ni based catalysts for CO2 reforming of CH4. The effects of Ce/Zr ratio and mesopore structure on promoting catalytic performances had been investigated. It was found that the catalyst supported on carrier with 50/50 Ce/Zr ratio behaved the highest catalytic activity. The reason for this might be that the mesoporous ceria–zirconia solid solution carrier contributed to the activation of CO2 by its own redox property. Compared with the catalyst without obvious mesostructure, the current mesoporous catalyst performed higher catalytic activity and better catalytic stability, demonstrating the advantages of the mesostructure. On the one hand, the predominant textural properties such as large surface area, big pore volume, and uniform channel helped to the high dispersion of the Ni particles among the mesoporous framework, finally leading to higher catalytic activity. On the other hand, the mesoporous matrix could stabilize the Ni nanoparticles under severe reduction and reaction conditions by the “confinement effect”, committed to better catalytic stability. Besides, the properties of the coke over the mesoporous catalyst were also carefully studied. Generally, these mesoporous nanocrystalline ceria–zirconia solid solutions were a series of promising catalytic carriers for CO2 reforming of CH4.Graphical abstractHighlights► Mesoporous Ce–Zr solid solutions with various Ce/Zr ratios prepared by EISA method. ► These materials were utilized as supports for Ni based catalysts for dry reforming. ► The effect of Ce/Zr ratio on the catalytic activity was investigated. ► The role of mesopore in promoting catalytic activity and stability was examined. ► Properties of the coke over the mesoporous catalyst were studied.

Nickel nanoparticles (2–6 nm) were successfully deposited on MOF-5 (Zn4O(BDC)3, BDC = 1,4-benzenedicarboxylate) by a facile wet impregnation strategy to prepare Ni@MOF-5 employing Ni(acac)2 (acac = acetylacetonate) as the precursor in absolute ethanol solvent owing to the sensitivity to the moisture of MOF-5. Ni@MOF-5 exhibited excellent catalytic activity for hydrogenation of C = C bond using crotonaldehyde as a probe molecule under mild reaction conditions (conversion > 90.0%, selectivity > 98.0%, 2.0 MPa, 100 °C, 40 min). In addition, the catalyst could be reused and the structure of MOF-5 framework was still maintained. Therefore, MOF-5 promised a novel candidate of support for hydrogenation catalyst.The catalyst Ni@MOF-5 was successfully prepared by wet impregnation strategy, and exhibited much higher catalytic activity in hydrogenation for crotonaldehyde compared with that of the industrial catalyst Ni/SiO2.Highlights► Nickel nanoparticles were deposited on MOF-5 by wet impregnation strategy. ► Nickel nanoparticles were probably bonded to the outer surface of the support. ► Ni@MOF-5 exhibited very high catalytic activity in hydrogenation for crotonaldehyde. ► The catalyst could be reused several times with the maintenance of MOF-5 structure.

5-Hydroxymethylfurfural (HMF) and furfural, two of the most important intermediates derived from biomass, were directly produced from the hydrolysis of microcrystalline cellulose (MCC) with metal ions in ionic liquids as catalyst under mild conditions. Various ionic liquids were tested to obtain the most efficient catalyst, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1) showed the highest catalytic activity than others, and SO3H-functionalized ionic liquids exhibited better activity than non-functionalized ILs. The co-catalysis effect of Cr3+, Mn2+, Fe3+, Fe2+, Co2+ were much better than other metal ions, with a catalytic amount of these metal ions, MCC conversion increased by 10–19%, and the selectivities of products were also improved obviously. The promoting catalysis of metal nitrates were not as expected as that of chlorides and sulfates, we suggested that nitrate anion may have a negative effect on the hydrolysis of MCC. Reaction conditions were optimized and reaction mechanism was proposed to explain the improved catalysis of metal chlorides and sulfates. Also, the recycling of catalyst was put forward in our system for MCC hydrolysis and these catalysts maintained good performances even after five runs. This simple and effective catalytic system may be valuable to facilitate energy-efficient conversion of cellulose into biofuels and platform chemicals.Graphical abstractHighlights► MCC was hydrolyzed into furans efficiently catalyzing by metal ions in ionic liquids. ► The co-catalysis of Cr3+, Mn2+, Fe3+, Fe2+, Co2+ were much better than other metal ions. ► SO3H-functionalized ionic liquids exhibited higher activity than non-functionalized ILs. ► A mechanism was proposed to explain the promoting catalysis of chlorides and sulfates. ► The catalyst could be easily recycled with stable catalytic activity.

Ordered mesoporous NiO–Al2O3 composite oxides with different nickel content were facilely synthesized via an improved evaporation induced self-assembly (EISA) strategy with Pluronic P123 as template in absolute ethanol solvent. The catalytic properties of the obtained mesoporous materials were investigated for the carbon dioxide reforming of methane reaction. These materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption and desorption characterization, H2 temperature-programmed reduction (TPR), and thermogravimetry (TG). It was observed that these catalysts with mesostructure presented both high catalytic activity and long stability. The improved catalytic performance was suggested to be closely associated with both the amount of “accessible” active centers for the reactants on the mesopore wall surface and the stabilisation of the active sites by the alumina matrix due to the “confinement effect” of the mesopores. The “confinement effect” existing among the mesoporous structure of the materials contributed to preventing Ni particles from sintering under severe reduction and reaction conditions. The stabilized Ni nanoparticles had strong resistance to carbon deposition, accounting for no deactivation after a 100 h long-term stability test at 700 °C. Thus, the ordered mesoporous NiO–Al2O3 composite oxides promised a novel and stable series of catalyst candidates for the carbon dioxide reforming of methane reaction.

Production of 5-hydroxymethylfurfural (HMF) and furfural from microcrystalline cellulose (MCC) was studied in 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1) with catalytic amount of MnCl2 under atmospheric pressure within 300 min at 150 °C, in which 88.62% of conversion was obtained. With the presence of a catalytic amount of MnCl2, HMF and furfural yields were up to 37% and 18%, respectively, and generated small amount of levulinic acid (LA) and the total reducing sugars (TRS). Dimer of furans compounds as the important by-products were analyzed through HPLC–MS; some small molecular substances, methane, ethane, CO, CO2 and H2, as gas products were detected using mass spectrometry analysis. Comparing with the previous reports, our catalytic system is simple, and it provides an effective route for the conversion of microcrystalline cellulose into biofuels and important platform chemicals.

A simple and effective process for the dehydration of fructose into 5-hydroxymethylfurfural (HMF) using ionic liquid 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1) as the catalyst was developed. High fructose conversion of 100% with HMF yield of 94.6% was obtained at 120 °C for 180 min reaction time in water-4-methyl-2-pentanone (MIBK) biphase system. Generally, the increase of water content had a negative effect on the reaction, the HMF selectivity decreased as the excessive elevation of temperature and prolonging of time, which suggested the decomposition of HMF. The ionic liquid IL-1 could be recycled and exhibited constant activity for six successful runs. This paper provided a new strategy for HMF production from fructose.

A simple and effective route for the production of 5-hydroxymethyl furfural (HMF) and furfural from microcrystalline cellulose (MCC) has been developed. CoSO4 in an ionic liquid, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1), was found to be an efficient catalyst for the hydrolysis of cellulose at 150 °C, which led to 84% conversion of MCC after 300 min reaction time. In the presence of a catalytic amount of CoSO4, the yields of HMF and furfural were up to 24% and 17%, respectively; a small amount of levulinic acid (LA) and reducing sugars (8% and 4%, respectively) were also generated. Dimers of furan compounds were detected as the main by-products through HPLC-MS, and with the help of mass spectrometric analysis, the components of gas products were methane, ethane, CO, CO2, and H2. A mechanism for the CoSO4-IL-1 hydrolysis system was proposed and IL-1 was recycled for the first time, which exhibited favorable catalytic activity over five repeated runs. This catalytic system may be valuable to facilitate energy-efficient and cost-effective conversion of biomass into biofuels and platform chemicals.Graphical abstractResearch highlights► Acid ionic liquid IL-1 showed highest catalytic activity among different ionic liquids. ► The CoSO4-IL-1 system was an efficient catalyst for the hydrolysis of MCC, the conversion reached 84–85%. ► 5-HMF and furfural yields were up to 24% and 17%, respectively. ► Small amount of levulinic acid and the total reducing sugars were also generated. ► A mechanism for the hydrolysis system was proposed and IL-1 was recycled for the first time.

Methanol synthesis from hydrogénation of CO2 is investigated over Cu/ZnO/Al2O3 catalysts prepared by decomposition of M(Cu, Zn)-ammonia complexes (DMAC) at various temperatures. The catalysts were characterized in detail, including X-ray diffraction, N2 adsorption-desorption, N2O chemisorption, temperature-programmed reduction and evolved gas analyses. The influences of DMAC temperature, reaction temperature and specific Cu surface area on catalytic performance are investigated. It is considered that the aurichalcite phase in the precursor plays a key role in improving the physiochemical properties and activities of the final catalysts. The catalyst from rich-aurichalcite precursor exhibits large specific Cu surface area and high space time yield of methanol (212 g/(Lcat · h); T = 513 K, p = 3 MPa, SV = 12000 h−1).

The performance of BaCl2-TiO2-SnO2 composite catalysts in oxidative coupling of methane reaction has been investigated. A series of BaCl2-TiO2, BaCl2-SnO2, TiO2-SnO2, and BaCl2-TiO2-SnO2 catalysts were prepared, and characterized by BET, XRD, XPS, CO2-TPD and H2-TPR, respectively. The synergistic effect among BaCl2, SnO2 and TiO2 compositions enhances the catalytic performance. The best C2 selectivity and ethylene yield are obtained on the catalyst with the equal molar amount of the three compositions (BaCl2: TiO2: SnO2 molar ratio of 1:1:1). The optimal reaction conditions are as follows: 800°C, 44 mL-min−1 for methane, 22 mL-min−1 for oxygen and a space velocity of 5000 mL-h−1-g−1, and the C2H4 yield over the catalyst is 20.1% with the CH4 conversion of 43.8% and C2 selectivity of 53.3%.

A novel BaCl2–TiO2–SnO2 catalyst was prepared and studied for the oxidative dehydrogenation of ethane (ODE). Slight changes in textual properties and crystal structures of the catalyst were observed after ODE reaction. Nonetheless, both Ba2 + and Cl− ions were found to segregate on catalyst surface during the reaction. The vital and positive effects of Cl− ions in the catalyst have been demonstrated by control experiments with catalyst free of Cl− ions. The BaCl2–TiO2–SnO2 catalyst show good activity and selectivity in ODE reaction, making it an alternative for ethylene synthesis using a low-cost feedstock such as ethane.Download full-size imageHighlights► A novel BaCl2–TiO2–SnO2 catalyst was prepared by grinding method for ODE reaction. ► Slight changes in textual properties and crystal structures were observed. ► The chloride ions in the catalyst play vital and positive roles. ► The catalyst shows good activity and selectivity in ODE reaction.

A series of mesoporous zirconium oxophosphate (M-ZrPO) with different P/Zr molar ratios (0–1.25) has been prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. After removing the structure-directing agents, the M-ZrPO with large specific surface area (160 m2 g−1), big pore volume (0.26 cm3 g−1) and narrow pore size distribution (5.64 nm) has been obtained. Small-angle X-ray diffraction (SXRD) and transmission electron microscopy (TEM) results showed that these materials had ordered mesoporous structure. With the increase of P/Zr, the textural properties of M-ZrPO could be improved. Moreover, the ordered mesostructure could be maintained even when treated at 800 °C, indicating the M-ZrPO had attractive thermal stability. NH3-TPD and pyridine-IR analyses showed the presence of abundant Brönsted and Lewis acid sites in the material. The M-ZrPO has been used successfully as solid acid catalyst and showed excellent performance in the ketalization reaction.

An ordered mesoporous CaO–Al2O3 composite oxide had been designed and prepared via improved evaporation induced self-assemble strategy (EISA). The resultant material was utilized as the support of Ni based catalyst for CO2 reforming of CH4. In order to study the roles of the ordered mesopore structure and basic modifier in promoting the catalytic properties toward the CO2 reforming of CH4 reaction, non-mesoporous CaO–Al2O3 without ordered mesostructure and ordered mesoporous Al2O3 without basic modifier were also synthesized, respectively. It was found that both the ordered mesostructure and CaO basic modifier showed significant effects in promoting catalytic activity, stability and suppressing the carbon deposition during their 100 h long term stability tests. Compared with traditional supported catalysts, the confinement effect of the mesoporous catalysts could effectively inhibit the thermal sintering of the Ni particles. Furthermore, the sorts of coke species over the spent catalysts and the mechanism of catalyst deactivation were also carefully investigated. Therefore, the present ordered mesoporous CaO–Al2O3 composite oxide will be a potential carrier for Ni-based catalysts for CO2 reforming of CH4 and even other reactions.

Mesoporous Mn–Zr composite oxides (M–MnZr) with a crystalline wall were designed and achieved by a facile one-pot evaporation-induced self-assembly (EISA) strategy. As proved by XRD, HRTEM and SAED characterization, the wall of the obtained mesoporous materials exhibited a typical tetragonal phase of ZrO2. In addition, the introduced manganese species were homogeneously dispersed in the mesoporous skeleton. N2-physisorption and TEM results showed that all the final materials possessed an obvious mesoporous structure accompanied by a large specific surface area (∼120 m2 g−1), big pore volume (∼0.2 cm3 g−1) and uniform pore size (∼4.9 nm). In addition, the liquid phase oxidation was chosen as the test reaction and the excellent catalytic performance of M–MnZr demonstrated their potential applications in oxidation reactions.

The relationship between the structure and Mo species in mesoporous molybdena–alumina catalysts and their catalytic performance for isobutane dehydrogenation has been investigated in detail. Characterization by XRD, HAADF-STEM, EDX, FT-IR, and N2 physisorption illustrated that ordered mesoporous catalysts (OM-Al, MoAl(F), and MoAl(C)) possessed an amorphous alumina phase and non-ordered mesoporous catalysts (M-Al and MoAl) exhibited a γ-Al2O3 phase. Mo species were highly dispersed over all the catalysts because Mo surface densities were about 1.0 Mo nm−2. Moreover, XPS and ICP-OES showed that Mo species were uniformly distributed over MoAl(F) with the Mo species confined in the ordered mesoporous structure. Higher dehydrogenation stability and a lower coke formation rate, albeit lower catalytic conversion, was obtained over MoAl(F) in comparison with those of MoAl(C) and MoAl on account of its stronger metal–support interaction, as shown by H2-TPR technique. The catalyst with a γ-Al2O3 phase exhibited stronger acidity and higher activity than the corresponding catalyst with an amorphous phase. The acidity of the catalysts was greatly enhanced by the addition of Mo species, according to the NH3-TPD characterization. However, not all the acid sites were active sites for dehydrogenation activity. The moderately and strongly acidic sites and the Mo species, including Mo6+ and lower valence Mo species, probably contributed to the dehydrogenation reactivity. Moreover, deactivation of the catalysts was mainly due to coke formation over the spent catalysts.

Mesoporous zirconium phosphotungstate (M-ZrPW), with large specific surface area (~170 m2 g−1), large pore volume (~0.25 cm3 g−1), uniform pore size distribution (~6.5 nm) and tunable W/Zr ratios (0–0.2), was successfully prepared via a facile one-pot evaporation-induced self-assembly (EISA) strategy. Small-angle X-ray diffraction (SXRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) characterizations showed that these materials had a mesoporous structure even when the W/Zr ratio reached up to 0.2. The tungsten species introduced via this strategy highly were dispersed among the wall of mesoporous framework. More importantly, the tungsten species greatly improved the Brønsted acidic property and catalytic activity in the Friedel–Crafts benzylation reaction. The highest activity was obtained at a W/Zr ratio of 0.2 with the strongest Brønsted acidity. In addition, the influences of various reaction parameters such as reaction time, amount of catalyst and calcination temperature of the catalyst, systematically investigated in this paper. Furthermore, the M-ZrPW showed a higher catalytic activity than H-Beta, H-ZSM5 and ZrPW prepared by the sol–gel method. Meanwhile, M-ZrPW could be reused at least for five cycles in the benzylation reaction without any notable decrease of catalytic activity.

Ordered mesoporous NiO–Al2O3 composite oxides with different nickel content were facilely synthesized via an improved evaporation induced self-assembly (EISA) strategy with Pluronic P123 as template in absolute ethanol solvent. The catalytic properties of the obtained mesoporous materials were investigated for the carbon dioxide reforming of methane reaction. These materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption and desorption characterization, H2 temperature-programmed reduction (TPR), and thermogravimetry (TG). It was observed that these catalysts with mesostructure presented both high catalytic activity and long stability. The improved catalytic performance was suggested to be closely associated with both the amount of “accessible” active centers for the reactants on the mesopore wall surface and the stabilisation of the active sites by the alumina matrix due to the “confinement effect” of the mesopores. The “confinement effect” existing among the mesoporous structure of the materials contributed to preventing Ni particles from sintering under severe reduction and reaction conditions. The stabilized Ni nanoparticles had strong resistance to carbon deposition, accounting for no deactivation after a 100 h long-term stability test at 700 °C. Thus, the ordered mesoporous NiO–Al2O3 composite oxides promised a novel and stable series of catalyst candidates for the carbon dioxide reforming of methane reaction.

Hybrid colloids (HCs) have shown distinct optical, electric, and optoelectronic properties from the components, mainly because of electronic interplay between the components. Here we investigate different charge transfer behaviors of dumbbell-structured CdSe-seeded CdS nanorods with metallic and semiconducting tip materials respectively studied by UV-vis and photoluminescence (PL) spectra, i.e. gold-tipped CdSe-seeded CdS nanorods and palladium sulfide-tipped CdSe-seeded CdS nanorods. They have shown remarkably different optical properties due to different charge transfer processes, i.e. one is only excited electrons transferred from the CdS shell to gold tips while the other is holes as well as electrons injected from the CdS shell into the palladium sulfide tips. The effect of the charge transfer on Rhodamine B (RhB) photodegradation is further investigated. Very interestingly, totally opposite effects were found, that is gold tips enhanced photodegradation rate while palladium sulfide tips vastly reduced photodegradation. Those phenomena are well explained by our proposed mechanism for the charge transfer. This study enables better design of HCs for improved photocatalysis and better photovoltaics.