Various erbium ion-exchanged montmorillonite K10 materials were prepared by an ion exchange method and were found to act as efficient solid acid catalysts. The catalytic materials synthesized in this work were characterized using a combination of X-ray fluorescence spectroscopy, N2 adsorption, powder X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma optical emission spectroscopy, X-ray photoelectron spectroscopy and NH3 temperature-programmed desorption, as well as by FT-IR spectra analysis following pyridine adsorption. These catalysts were also evaluated with regard to the hydrothermal conversion of cellulose to lactic acid. Lactic acid yields as high as 67.6% were obtained when reacting 0.3 g cellulose, 0.1 g catalyst and 30 mL water at 240 °C under 2 MPa N2 for 30 min. Upon recycling of the catalyst, the lactic acid yields decreased from 67.6 to 58.7 to 55.9% during the first, second and third trials. Beginning with the second trial the catalyst behaved as a true heterogeneous catalyst for the conversion of cellulose to lactic acid. The observed decreases in catalytic activity during recycling could be due to a combination of erbium ion leaching, deposition of carbon species in pores and partial structural changes in the catalyst.

A novel composite comprising Sn–Co nanoparticles encapsulated in grid-shell carbon spheres was synthesized. The composite comprised homogeneous grid-shell carbon spheres with a size of ∼1 μm and a shell thickness of ∼100 nm; SnCo and SnO2 nanoparticles with an average size of ∼16 nm were uniformly embedded in the shells and internal grids of the carbon spheres. This composite showed high capacity, good rate performance and excellent capacity retention when it was applied as an anode material for lithium-ion batteries.

Thermally expanded graphene oxide (TEGO) supported PtAu alloy nanoparticles with various compositions was prepared, and then characterized using a combination of atomic absorption spectroscopy, powder X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. These catalysts were evaluated for the aerobic oxidation of glycerol in base-free aqueous solution. The results showed that PtAu(7:1)/TEGO exhibited the optimum activity for the conversion of glycerol among all the catalysts. Glycerol conversion of 60.4% and selectivities of 53.5% glyceric acid (GLYA), 25.7% glyceraldehydes (GLYDE), 11.6% dihydroxyacetone (DHA), and 3.8% glycolic acid (GLYCA) were obtained when reacting an aqueous solution of glycerol (0.3 M, 20 mL) at 60 °C under 0.3 MPa O2 for 4 h in the presence of 0.023 g PtAu(7:1)/TEGO catalyst. Moreover, the reusability of PtAu(7:1)/TEGO was investigated, and a reaction mechanism for the oxidation of glycerol was proposed.

Au/ZnO and Au/Al2O3 catalysts with various mean Au particle diameters (2.0–7.4 nm) were prepared by the deposition of pre-formed Au colloids. These catalysts were evaluated in the oxidative esterification of ethylene glycol to methyl glycolate. The results show that the catalytic activity per surface Au atom is independent of Au particle diameter in the range of 3–7.4 nm, whereas smaller Au particles (~2.0 nm) show an inferior activity. This behavior was observed on both Au/ZnO and Au/Al2O3 catalysts. This observed correlation between activity and Au particle diameter confirms the assertion that only exposed atoms are catalytically active. We prepared gold nanoparticles with a uniform mean diameter of ~3 nm loaded on various supports, i.e. ZnO, Al2O3, SiO2, TiO2 and CeO2. Among these five catalysts, Au/ZnO gave the best catalytic activity in the reaction followed by Au/Al2O3. Au/SiO2, Au/TiO2 and Au/CeO2 gave significantly lower activities. The variation in catalytic behavior of these gold catalysts on different supports originates from differences in the anchoring of the supported Au particles, the gold oxidation state, the gold–support interaction, and the acidity of the support.

•Ni/CeZrO catalysts for glycerol steam reforming were prepared.•High hydrogen yield with low CO and methane content was obtained.•Ni/CeZrO with 77.3% Ce has good resistance to carbon deposition.Ni catalysts supported on the CeZrO solid solution with different compositions were prepared and characterized by powder X-ray diffraction, N2 physical adsorption, H2 chemisorption, temperature programmed reduction, and temperature programmed oxidation. Hydrogen production from the steam reforming of glycerol over these catalysts was investigated. Among the catalysts, Ni/CeZrO-3 with 77.3% Ce content shows the highest conversion of glycerol and selectivity of H2 as well as the best stability during the reaction. This could be due to the fact that Ni/CeZrO-3 has the highest metal dispersion which can prevent or minimize the carbon formation on the surface of the catalyst. On the other hand, the catalyst could generate the most mobile oxygen species during reaction, thus, decoking activity will likely be enhanced through the participation of the lattice oxygen. The effects of reaction temperature, H2O/glycerol molar ratio, and the feed flow rate on the steam reforming of glycerol over Ni/CeZrO-3 were also examined.

•The α-MoO3/graphene composites were prepared via an in situ hydrothermal synthesis.•The MoO3/G-27 anode delivers an initial reversible capacity of 977.7 mAh g−1.•After 80 cycles it has a reversible capacity of 869.2 mAh g−1 at 50 mA g−1.The α-MoO3/graphene composites (MoO3/G) were prepared via an in situ hydrothermal synthesis. The composites were characterized using various characterization techniques including powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and the electrochemical performance test. The results show that these MoO3/G composites exhibit high capacity and good cycle stability when used as the lithium-ion battery anode. Among all the samples, the MoO3/G-27 reveals the best electrochemical performance with an initial charge capacity of 977.7 mAh g−1 at a current density of 50 mA g−1, the first coulombic efficiency of 69.5%. After eighty cycles the electrode still maintains a capacity of 869.2 mAh g−1, giving high capacity retention of 88.9%. The good electrochemical performance of the composite anode is close related to its structure, in which the MoO3 nanobelts are not only homogeneously anchored on the surface but also embedded in the interlayer of the graphene sheets; hence the volume change and aggregation of the MoO3 nanobelts during lithium ion insertion/extraction process can be effectively hindered. On the other hand, graphene itself is an electronic conductor; the graphene and MoO3 nanobelts connect closely, which offers large electrode/electrolyte contacting area, short path length for Li+ transporting during lithium insertion and extraction.

•MoO2-loaded porous carbon hollow sphere composite materials were synthesized.•MoO2 particles are homogeneously embedded in the shells of hollow carbon spheres.•The composite with 44.2% of MoO2 exhibits a capacity of 574 mAh g−1 at 50 mA g−1.•After 80 cycles it has a reversible capacity of 640 mAh g−1.In this study, novel MoO2-loaded porous carbon hollow sphere composite materials were synthesized. The composites consisted of homogeneous hollow microspheres with a size of ∼0.7 ± 0.1 μm and a shell thickness of ∼70 nm; MoO2 nanoparticles with an average size of ∼12 nm were uniformly dispersed in the shells of the porous carbon hollow spheres (PCHS). The MoO2/PCHS composites showed high capacity and excellent capacity retention when they were applied as an anode material for Li ion batteries. The composite containing 44.2% of MoO2 revealed a reversible capacity of 574 mAh g−1 at a current density of 50 mA g−1, and a first coulombic efficiency of 61%. After 80 cycles, this composite still retained a capacity of 640 mAh g−1. The good electrochemical performance could be due to the fact that the MoO2 nanoparticles were homogeneously embedded in the shells of the porous carbon hollow spheres in the composites, which effectively prevented volume change or aggregation of the MoO2 nanoparticles during the lithium ion insertion/extraction process. The porous carbon hollow spheres with good electronic conductivity and high surface area offered a large electrode/electrolyte contact area, and a short path length for the Li+ transport.

Lanthanide triflates are excellent catalysts for the hydrothermal conversion of cellulose to lactic acid. Under the optimum conditions, as high as 89.6% yield of lactic acid was obtained by using Er(OTf)3 as the catalyst. This catalyst could be reused at least five times without obvious loss of activity.

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over Nb2O5 derived from calcination of niobic acid at various temperatures (300–700 °C). The catalysts were characterized by powder X-ray diffraction, N2 physical adsorption, temperature-programed desorption of NH3, n-butylamine titration using Hammett indicators, infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy. It was found that both catalytic activity and surface acid sites decrease with increasing calcination temperatures. The Nb2O5 derived from calcination of niobic acid at 400 °C reveals the maximum yield of HMF among all the catalysts, although the amount of acid sites on the catalyst is lower than that on the sample calcined at 300 °C. The results suggest that the presence of larger amounts of strong acid sites on the surface of the Nb2O5 calcined at 300 °C may promote side reactions. The Nb2O5 prepared at 400 °C shows 100% fructose conversion with 86.2% HMF yield in DMSO at 120 °C after 2 h. The activity of the catalyst decreases gradually during recycle because of coke deposition; however, it can be fully recovered by calcination at 400 °C for 2 h, suggesting that this catalyst is of significance for practical applications.Graphical abstractHighlights► 5-Hydroxymethylfurfural was synthesized by the catalytic dehydration of fructose. ► Nb2O5 calcined at 400 °C is a highly efficient catalyst. ► 100% fructose conversion with 86.2% HMF yield was obtained at 120 °C for 2 h. ► This Nb2O5 catalyst was deactivated gradually during recycle due to carbon deposition. ► The activity of the catalyst can be fully recovered by calcination.

Glycerol carbonate was synthesized by the oxidative carbonylation of glycerol catalyzed by the commercial Pd/C with the aid of NaI. High conversion of glycerol (82.2%), selectivity to glycerol carbonate (>99%), and TOF (900 h−1) were obtained under the conditions of 5 MPa (pCO:pO2 = 2:1), 140 °C, 2 h. The highly active palladium species were generated in situ by dissolution from the carbon support and stabilized by re-deposition onto the support surface after the reaction was finished. Palladium dissolution and re-deposition were crucial and inherent parts of the catalytic cycle, which involved heterogeneous reactions. This Pd/C catalyst could be recycled and efficiently reused for four times with a gradual decrease in activity. Moreover, the influences of various parameters, e.g., types of catalysts, solvents, additives, reaction temperature, pressure, and time on the conversion of glycerol were investigated. A reaction mechanism was proposed for oxidative carbonylation of glycerol to glycerol carbonate.

The catalytic alcoholysis of fructose in methanol to methyl levulinate was performed by using phosphotungstic acid iron catalysts. The catalysts were characterized by powder X-ray diffraction, infrared spectroscopy, and X-ray fluorescence spectroscopy. The results showed that the exchanging of H+ with Fe3+ ions could modify the acidity of H3PW12O40 and introduce some Lewis acidity into the molecules. The highest yield of methyl levulinate was obtained over the Fe-HPW-1 catalyst. This catalyst showed 100 % fructose conversion with 73.7 % yield of methyl levulinate at 130 °C, 2 MPa for 2 h, and it could be reused at least five times without obvious loss of activity. The results suggest that the combination of Brønsted acidity with some Lewis acidity could effectively promote the conversion of fructose in methanol to methyl levulinate.

Nanostructure Sn–Co–C composites with different compositions are synthesized by a simple solution polymerization using inexpensive raw materials followed by pyrolysis in nitrogen atmosphere. The nanostructure Sn–Co–C composites are characterized using various analytic techniques. The results show that the electrochemical performances of the composites are strongly dependent on their structure and composition. Among these composites the Sn–Co–C-1 with a weight composition of Sn0.31Co0.09C0.6 exhibits high reversible capacity and excellent cycleability when used as an anode for rechargeable lithium ion batteries. This composite is composed of SnCo2, SnCo, Sn and amorphous carbon, and the nanoparticles of SnCo2, SnCo and Sn are uniformly dispersed into the amorphous carbon matrix, the average diameter of these metal nanoparticles is 8.44 nm.

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) was investigated by using various rare earth metal trifluoromethanesulfonates, that is, Yb(OTf)3, Sc(OTf)3, Ho(OTf)3, Sm(OTf)3, Nd(OTf)3 as catalysts in DMSO. It is found that the catalytic activity increases with decreasing ionic radius of rare earth metal cations. Among the examined catalysts, Sc(OTf)3 exhibits the highest catalytic activity. Fructose conversion of 100% and a HMF yield of 83.3% are obtained at 120 °C after 2 h by using Sc(OTf)3 as the catalyst. Moreover, the catalytic dehydration of fructose was also carried out in different solvents, for example, DMA, 1,4-dioxane, and a mixture of PEG-400 and water. The results show that among the solvents DMSO is the most efficient in promoting the dehydration of fructose to HMF, and no rehydration byproducts such as levulinic acid and formic acid are detected.The catalytic activity of various rare earth metal trifluoromethanesulfonates in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) increases with decreasing ionic radius of rare earth metal cations.

A new catalyst of copper ion-containing ionic liquids immobilized on SBA-15 was prepared and characterized by XRD, HRTEM, N2 physical adsorption, FTIR, elemental analysis, TGA, AA, and XPS. The CuBr2–PyIL/SBA-15 catalyst was found to be more active and selective than CuBr2 and CuBr2/SBA-15 prepared by the conventional impregnation method in the synthesis of dimethyl carbonate by oxidative carbonylation of methanol. Although the CuBr2–PyIL/SBA-15 catalyst deactivated rapidly during the initial three runs, it still maintained a comparable activity with the fresh CuBr2/SBA-15 catalyst after three recycling.

Zirconia precursor nanowires were synthesized via the solvothermal reaction of zirconium tetra-n-propoxide Zr(OPrn)4 with ethylene glycol and 1-butyl-3-methyl imidazolium tetrafluoroborate ionic liquid at 160 °C. The as-synthesized nanowires were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), thermogravimetric and differential scanning calorimetric (TG-DSC) analysis, and infrared spectroscopy (IR), etc. The length of the as-synthesized nanowires reaches ∼20 μm, and the width ∼50 nm, giving an aspect ratio of a few hundreds. Upon calcination at elevated temperatures, the zirconia precursor nanowires transform from relative dense structure into highly porous ZrO2 nanowires consisting of interconnected nanocrystallites; in addition the length of the nanowires is greatly reduced. Cyclic voltammetry measurement shows that the modification of the graphite electrode with the ZrO2 nanowires greatly enhances sensitivity of the detection of vanadium, suggesting that ZrO2 nanowires may find important applications in vanadium(V) determination using electroanalytical methods with chemically modified electrode technique.Zirconia precursor nanowires with high aspect ratio were synthesized by a novel, facile solvothermal reaction of zirconium tetra-n-propoxide Zr(OPrn)4 with ethylene glycol and l-butyl-3-methyl imidazolium tetrafluoroborate ionic liquid.

Rosette-like ammonium flurorzirconate (NH4Zr2F9) aggregates have been synthesized via a novel reaction route by using zirconium oxychloride, urea, 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) and hydrochloric acid in ethanol solution. The as-synthesized NH4Zr2F9 can be changed from rosette-like aggregates to hexagonal plates by varying synthesis conditions. Upon calcination at high temperature NH4Zr2F9 transforms from relative dense structure into highly porous ZrO2 with similar morphology consisting of interconnected nanocrystallites.

Hollow ZrO2 microspheres with mesoporous shells have been synthesized by a novel hydrothermal reaction of zirconium oxychloride in the presence of urea, hydrochloric acid, and ethanol. The morphology and shell thickness of the hollow microspheres can be controlled by varying synthesis conditions. After calcination at high temperature, the morphologies of the hollow microspheres are essentially preserved. Pt catalyst supported on the hollow calcined ZrO2 microspheres exhibits more excellent catalytic performance in CO oxidation than those on ZrO2 powders derived from conventional precipitation methods.Hollow ZrO2 microspheres with mesoporous shells have been successfully synthesized by a novel hydrothermal reaction of zirconium oxychloride in the presence of urea, hydrochloric acid, and ethanol.

Tin oxide (SnO2) microspheres with an average 2.5 μm in diameters have been successfully synthesized through a rapid hydrothermal process heating by microwave in the presence of an ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate. X-ray diffraction, scanning electron microscopy and transmission electron microscopy are used to characterize the morphology and crystalline structure of the microspheres. The as-synthesized SnO2 microspheres exhibit a tetragonal rutile structure. The mechanism of the microspheres formation is proposed.Tin oxide (SnO2) microspheres with an average 2.5 μm in diameters have been successfully synthesized through a rapid hydrothermal process heating by microwave in the presence of an ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate.

Curing reaction of the as-spun fiber derived from melt-spinning of a novolac resin in a solution of formaldehyde and hydrochloric acid was carried out under microwave irradiation by controlling the reaction time. IR spectroscopy, scanning electron microscopy, and dynamic mechanical analysis were employed to characterize the change of structure and mechanical performance of these phenolic fibers. At the heating rate of 1.2 °C min−1 or in a period of 86 min the homogeneous highly crosslinked phenolic fiber was obtained with the maximum tensile strength being similar with that of the fiber cured under conventional heating reflux (8 h), suggesting that microwave irradiation promotes not only the diffusion of +CH2OH from the skin into the inner layer of the fiber but also the reaction of +CH2OH with the phenolic ring in a suitable extent. During pyrolysis the increase of crosslinking degree in the phenolic fibers diminishes the formation of low molecular weight compounds and promotes the formation of graphite layers.

The crystal structure of ε-VOPO4 was determined in the space group Cc   from X-ray powder diffraction data using a rigid body approach. The resulting structure is compared to a recently published, slightly different structure model (space group P21/nP21/n) using Rietveld refinement. It was found that the new Cc model consistently yields a better fit to the observed data and exhibits a less distorted, more stable geometry. The crystal structure of ε-VOPO4 is discussed in comparison to β-VOPO4, monoclinic VPO4⋅H2O, and other related structures.

Au/ZnO and Au/Al2O3 catalysts with various mean Au particle diameters (2.0–7.4 nm) were prepared by the deposition of pre-formed Au colloids. These catalysts were evaluated in the oxidative esterification of ethylene glycol to methyl glycolate. The results show that the catalytic activity per surface Au atom is independent of Au particle diameter in the range of 3–7.4 nm, whereas smaller Au particles (~2.0 nm) show an inferior activity. This behavior was observed on both Au/ZnO and Au/Al2O3 catalysts. This observed correlation between activity and Au particle diameter confirms the assertion that only exposed atoms are catalytically active. We prepared gold nanoparticles with a uniform mean diameter of ~3 nm loaded on various supports, i.e. ZnO, Al2O3, SiO2, TiO2 and CeO2. Among these five catalysts, Au/ZnO gave the best catalytic activity in the reaction followed by Au/Al2O3. Au/SiO2, Au/TiO2 and Au/CeO2 gave significantly lower activities. The variation in catalytic behavior of these gold catalysts on different supports originates from differences in the anchoring of the supported Au particles, the gold oxidation state, the gold–support interaction, and the acidity of the support.