Xiaojing Hu

CO oxidation over Cu2O deposited on 2D continuous lamellar g-C3N4

Cu2O deposited on 2D continuous lamellar g-C3N4 (Cu2O/g-C3N4) was prepared via a facile impregnation–chemical reduction procedure. The composition, structure and morphology of as-prepared Cu2O/g-C3N4 were characterized by XRD, SEM, TEM, CO-TPR, FT-IR and nitrogen adsorption, respectively. The influence of Cu2O loading on the performances of Cu2O/g-C3N4, e.g. adsorption ability for methyl orange (MO) and the stability as well as catalytic activity for CO oxidation, was investigated. The changing trend of adsorption ability and the catalytic activity of Cu2O/g-C3N4 moved in the same direction. When the mass ratio of Cu2O to g-C3N4 was 4 : 10, the as-prepared composite exhibited the strongest adsorption ability and the highest catalytic activity; it also showed excellent stability in CO oxidation and over it the 100% conversion of CO was kept for more than 12 h under reaction conditions. The strong adsorption ability and good catalytic performance of Cu2O/g-C3N4 were ascribed to the synergetic effects between g-C3N4 and Cu2O as well as the improved dispersibility and the decreased particle size of Cu2O.

Synthesis and characterization of TiO2 nanotube supported Rh-nanoparticle catalysts for regioselective hydroformylation of vinyl acetate

Three procedures: the impregnation-borohydride reduction procedure, the impregnation-alcohol reduction procedure and the impregnation-photoreducing procedure, were utilized for preparing TiO2 nanotube supported rhodium nanoparticle catalysts, in which rhodium acetate was used as a rhodium source. Catalysts were characterized with TEM, ICP, XPS and XRD; their catalytic performances for hydroformylation of vinyl acetate were evaluated. Of these catalysts prepared by three different methods, the catalyst prepared by the impregnation-photoreducing procedure showed the highest catalytic activity under the same reaction conditions. The effects of pressure of syngas, solvents, temperature, Rh content and reaction time on the hydroformylation were examined in detail. Under the optimized reaction conditions, the conversion of vinyl acetate can reach at 100%; the chemoselectivity for aldehydes was 74.70% and the regioselectivity for the branched aldehyde was 95%.

Characterization of Pt catalysts supported by three forms of TiO2 and their catalytic activities for hydrogenation

Three forms of TiO2, commercial TiO2 powder, hydrogen titanate nanotubes obtained by hydrothermal treatment, and the thermally stable TiO2 nanotubes prepared by treating hydrogen titanate nanotubes with a sol containing titanium, were used as supports, and Pt nanoparticles were deposited on the supports via the photodeposition method. The catalytic performances of as-prepared and calcined Pt/TiO2 catalysts for the hydrogenation reaction of cyclohexene were evaluated. The results showed that the effects of the support and calcination temperature on the catalytic performances of Pt/TiO2 catalysts were obvious and significant. The thermally stable nanotubular TiO2-supported Pt catalyst exhibited better catalytic performance than the other TiO2-supported Pt catalysts. In addition, it was discovered that the calcination can enhance the catalytic activity of Pt/TiO2 for hydrogenation greatly.

Highly photostable palladium-loaded TiO2 nanotubes and the active species in the photodegradation of methyl orange

Abstract Highly photostable palladium-loaded TiO 2 nanotubes (Pd/TNTs) were prepared by a simple photo-decomposition method and characterized by inductively coupled plasma, X-ray diffraction, UV-visible light diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, N 2 adsorption-desorption, and photocurrent measurement. TEM images showed that the samples had a tubular structure. XPS results revealed that most of the palladium was present as Pd 0 . The photocatalytic performance was evaluated by monitoring the catalytic activity for the degradation of methyl orange solution under both UV and simulated sunlight irradiation. Pd/TNTs with 0.3 wt% Pd displayed higher activity than P25. The active species in the photocatalytic process were investigated by using different types of active species scavengers. h vb + was the major reactive species in the photodegradation over the Pd/TNTs.

Boron modified TiO2 nanotubes supported Rh-nanoparticle catalysts for highly efficient hydroformylation of styrene

The boron modified TiO2 nanotube (B-TNTs) samples were prepared via a hydrothermal treatment and an impregnation method, using boric acid as the boron precursor. Characterization methods including XRD, XPS, SEM and TEM were carried out to elucidate the structural evolution of the samples on the introduction of boron. The samples retained their crystallographic phase as anatase TiO2 after the modification with boron. Rh/B-TNTs catalysts, for the catalytic hydroformylation of styrene, were systematically investigated. It is shown that the boron loading and the B-TNTs preparation method have great effect on the behavior of the catalyst. Experimental results showed that the Rh/B-TNTs-hydrothermal-10% catalyst exhibited the best catalytic performance, affording the highest TOF (up to 18 458 h−1). These findings showed that boron modified TNTs can be an important milestone in the search for efficient heterogeneous catalysts for olefins hydroformylation.

Preparation, characterization and photocatalytic performances of materials based on CS2-modified titanate nanotubes

CS2-modified titanate nanotubes (CS2/TiO2-NTs) are fabricated by reaction of CS2 and Ti-O−Na+ species on titanate nanotubes. Pb2+ ions are coated on the modified nanotubes by ion exchange (Pb/CS2/TiO2-NTs). The products are characterized by means of nitrogen adsorption-desorption isotherms at 77 K (BET method), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), atomic absorption spectrometry (AAS), and diffuse reflectance spectroscopy (DRS). The photocatalytic performances of the products are evaluated by monitoring their catalytic activities for degradation of methyl orange under UV light irradiation. The effects of calcination temperature and atmosphere on the photocatalytic performance are investigated. The results reveal that the photocatalytic activities of CS2/TiO2-NTs and Pb/CS2/TiO2-NTs are far higher than that of primary nanotubes, and the optimum calcination temperature is 500 °C under N2 atmosphere. It is also discovered that physically adsorbed Pb2+ ions affect the photocatalytic activity of Pb/CS2/TiO2-NTs obviously. The photocatalytic activity of washed Pb/CS2/TiO2-NTs is higher than that of the unwashed one under the same thermal treatment and reaction conditions.