We report a general reaction container effect in the nanocasting synthesis of mesoporous metal oxides. The size and shape of the container body in conjunction with simply modifying the container opening accessibility can be used to control the escape rate of water and other gas-phase byproducts in the calcination process, and subsequently affect the nanocrystal growth of the materials inside the mesopore space of the template. In this way, the particle size, mesostructure ordering, and crystallinity of the final product can be systemically controlled. The container effect also explain some of the problems with reproducibility in previously reported results.

Nitrogen-incorporated zeolites have drawn much attention as a new family of basic solid materials and N atoms are expected to be introduced into the frameworks of zeolites. In this study, nitrogen-incorporated ZSM-5 zeolites were prepared by temperature-programmed nitridation and their physicochemical properties were characterized by means of XRD, SEM and BET techniques. Combined a detailed IR characterization with a theoretical IR simulation, the bands relating to bridging Si–N(H)–Si groups at 1151 and 985 cm−1 were observed in the IR fingerprint region of nitrogen-incorporated zeolites. The results confirmed that N atoms have been introduced into the framework of ZSM-5 zeolites by nitridation to form basic –NH– species, which was also supported by results of 29Si MAS NMR characterization. Furthermore, the basic catalytic properties of nitrogen-incorporated ZSM-5 zeolites were evaluated by Knoevenagel condensation of benzaldehyde and malononitrile and enhanced conversion of benzaldehyde was achieved.

Mesoporous nitrided MCM-41 was synthesized and physically characterized. The nitrogen species are predominantly present as imido NH groups as shown by infrared spectroscopy. The NH groups are located in the framework and are therefore inaccessible for reactant and probe molecules. Deuterium exchange experiments support this interpretation. The surface exposes Si–OH groups which are identical to silanol groups on pure silica; basic sites could not be detected by neither deutero-chloroform nor methylacetylene. We infer that a small number of NH2 groups are located at the surface of the pore walls which may be responsible for the activity for base-catalyzed reactions.

Cell-assemblies with different cell shapes were used as macrotemplates in the bioinspired synthesis of hierarchical macro-mesoporous titania with tunable macroporous morphology and enhanced photocatalytic performance.

Metal cation (metal = Cu, In and La) ion exchanged ZSM-5 zeolites as catalysts for the NO selective reduction by propane and propene in excess oxygen. The surface reactions of HC-SCR over catalysts were investigated through in situ DRIFTS method. For C3H8-SCR, adsorbed nitrate species (–NO3) were observed as main reaction intermediates and they could react with gaseous propane to produce N2, H2O and CO2. While for C3H6-SCR, adsorbed amine species (–NH2) were observed as main reaction intermediates and they could react with NO or NO2 to produce the final products. The different reaction pathways for C3H8-SCR and C3H6-SCR over catalysts were proposed based on the DRIFTS results and the main factors controlling the activities of catalysts were discussed in details. The competing adsorption between NO–O2 and HC–O2 on the Brønsted acid sites of catalysts was responsible for the different reaction pathways in HC-SCR.

Size-controlled and coated magnetite nanoparticles with glucose and gluconic acid have been successfully synthesized via a simple and facile hydrothermal reduction route using a single iron precursor, FeCl3, and a combination of the inherent chemical reduction capability of sucrose decomposition products and their inorganic coordinating ability. The particle size can be easily controlled in the range of 4−16 nm. Results obtained with and without the addition of sucrose indicate that sucrose is required for the formation of nanoscale and coated magnetite instead of the much larger hematite. Mass spectrometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetry analysis were used to investigate the formation mechanism of the coated nanomagnetite from the single Fe(III) precursor in sucrose. Sucrose acts as a bifunctional agent: (i) it decomposes into reducing species, causing partial reduction of the Fe3+ ions to Fe2+ ions as required for the formation of Fe3O4 and (ii) acts as the source of a capping agent to adjust the surface properties and enable the formation of nanoscale particles. The saturation magnetization of the as-obtained magnetite is measured and greatly related to the particle size.

Unique N-doped TiO2 nanowires with one-dimensional nanostructure were synthesized in presence of NH3 gas at different temperature with titanate nanowires as precursor. Structure and morphology of the obtained samples were investigated by TEM, HRTEM, SEM, XRD, XPS, and UV–Vis. The results revealed that a clear visible-light response could be induced by N-doping. Nanowire structure was maintained after N-hybridization of TiO2 framework even at 600 °C, while distance between two contiguous layers shrinked a little. The incorporated nitrogen atoms are located in position of oxygen in TiO2 lattice to form O–Ti–N structure according to XPS result. An excellent photocatalytic activity of nitrogen-doped TiO2 nanowires for degradation of methyl orange was achieved.

It was found that Si-MCM-41 mesoporous molecular sieves as a support of noble metal Pt could be used for the selective catalytic reduction of NO by hydrogen (H2-SCR) under lean-burn conditions. Pt/Si-MCM-41, together with Pt/Si-ZSM-5 and Pt/SiO2, was characterized by X-ray diffraction analysis (XRD), nitrogen adsorption/desorption, hydrogen adsorption, and transmission electron microscopy (TEM). The results indicated that Pt/Si-MCM-41 had the best H2-SCR activity in comparison with Pt/Si-ZSM-5 and Pt/SiO2 catalysts and that the maximum conversion of NO was up to 60.1% at 100 °C and a gas hourly space velocity (GHSV) of 80000 h–1 under lean-burn conditions. Characterization showed that the large surface area and pore volume of MCM-41 favored the dispersion of Pt. The maximum NO conversion of Pt/Si-MCM-41 catalyst decreased obviously to 15% at 120 °C when the pore structure of Si-MCM-41 support was destroyed. The reaction mechanism over Pt/Si-MCM-41 was investigated using in situ diffuse reflectance infrared spectroscopy (DRIFTS), which revealed that the main reaction intermediates should be nitrate species during NO reduction.

Catalytic hydrogenation of nitrate (NO3−) in water on Pd−Cu ensembles has been denoted as a promising denitridation method, but its hydrogenation selectivity remains challenging. In this study, the hydrogenation selectivity of nitrate on the Pd−Cu/TiO2 systems was discussed mainly concerning the size effect of Pd−Cu ensembles in a gas−liquid cocurrent flow system. Demonstrated by their TEM images, homogeneous morphologies as well as narrow size distributions of Pd−Cu ensembles on titania have been prepared by a facile photodeposition process, and the size of the ensembles was controlled and varied with the total metal loadings. The different XRD patterns and XPS spectra of Pd−Cu/TiO2 catalysts from their corresponding monometallic counterparts suggested the formation of Pd−Cu complex on the surface of TiO2. It is first indicated that the hydrogenation selectivity of nitrate generally depends on the size of active phase with critical size of approximately 3.5 nm, below which NO2− becomes the predominant product instead of nitrogen. Ammonium production was increasing slowly throughout the reaction, but this can be efficiently restrained by bubbling CO2. The optimal catalytic activity and nitrogen selectivity of 99.9% and 98.3% respectively could be achieved on the Pd−Cu/TiO2 catalyst with average size of 4.22 nm under the modification of CO2 after approximately 30 min reduction. The catalytic activities of nitrite on several Pd−Cu bimetallic catalysts were examined to strongly depend on the size of active metal, as is well responsible for the observed distinct hydrogenation selectivity of nitrate.

A novel and facile β-cyclodextrin-assisted method has been employed in this study to prepare superparamagnetic Fe3O4 nanoparticles from a single iron precursor of FeCl3·6H2O. Various characterization involving X-ray diffraction (XRD), standard and high-resolution transmission electron microscopy (TEM and HRTEM), electron diffraction (ED), and Raman spectroscopy has integrally testified the formation of pure magnetite nanoparticles with homogeneous morphology. The size of nanoparticles can be adjusted from 4 to 17 nm by varying the concentration of β-cyclodextrins. The success is ascribed to in situ formation of reducing sugar originating from the self-decomposition of β-CD under the reaction conditions, which partly reduces Fe3+ ions into Fe2+ ions for final formation of Fe3O4. Another function of β-CD is also discussed: that it acts as a coating agent to prevent particle growth and agglomeration, which allows the formation of nanoscale and superparamagnetic magnetite with different particle sizes. The saturation magnetization (Ms) of the as-obtained magnetite is measured and is strongly related to the particle size.

Cell-assemblies with different cell shapes were used as macrotemplates in the bioinspired synthesis of hierarchical macro-mesoporous titania with tunable macroporous morphology and enhanced photocatalytic performance.