Jinqing Jiao

3D ordered macroporous TiO2-supported Pt@CdS core–shell nanoparticles: design, synthesis and efficient photocatalytic conversion of CO2 with water to methane

A series of photocatalysts of three-dimensionally ordered macroporous (3DOM) TiO2-supported core–shell structured Pt@CdS nanoparticles were facilely synthesized by the gas bubbling-assisted membrane reduction-precipitation (GBMR/P) method. All the catalysts possess a well-defined 3DOM structure with interconnected networks of spherical voids, and the Pt@CdS core–shell nanoparticles with different molar ratios of Cd/Pt are well dispersed and supported on the inner wall of uniform macropores. The 3DOM structure can enhance the light-harvesting efficiency due to the increase of the distance of the light path by enhancing random light scattering. And the all-solid-state Z-scheme system with a CdS(shell)–Pt(core)–TiO2(support) nanojunction is favourable for the separation of photogenerated electrons and holes because of the vectorial electron transfer of TiO2 → Pt → CdS. 3DOM Pt@CdS/TiO2 catalysts exhibit super photocatalytic performance for CO2 reduction to CH4 under simulated solar irradiation. Among the as-prepared catalysts, the 3DOM Pt@CdS/TiO2-1 catalyst with the moderate thickness of a CdS nanolayer shell shows the highest photocatalytic activity and selectivity for CO2 reduction, e.g., its formation rate of CH4 is 36.8 μmol g−1 h−1 and its selectivity for CH4 production by CO2 reduction is 98.1%. The design and versatile synthetic approach of the all-solid-state Z-scheme system on the surface of 3DOM oxides are expected to throw new light on the fabrication of highly efficient photocatalysts for CO2 reduction to hydrocarbon.

Preparation of ultrafine Ce-based oxide nanoparticles and their catalytic performances for diesel soot combustion

Abstract The ultrafine Ce-based oxide nanoparticles with different element dopings (Zr, Y) were synthesized by the method of micropores-diffused coprecipitation (MDC) using ammonia solution as the precipitation agent. The activities of the catalysts for soot oxidation were evaluated by the temperature-programmed oxidation (TPO) reaction. Ce-based oxides prepared in this study exhibited high catalytic activity for soot oxidation under the condition of loose contact between soot particles and catalysts, and the catalytic activity of ultrafine Ce 0.9 Zr 0.1 O 2 nanoparticle for soot combustion was the highest, whose T 10 , T 50 and S CO 2 m was 364, 442 °C and 98.3%, respectively. All catalysts were systematically characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brumauer-Emett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). It was indicated that the MDC method could prepare the ultrafine Ce-based oxide nanoparticles whose the crystal lattice were perfect, and the BET surface area and average crystal size of the ultrafine nanoparticles changed with the different element dopings (Zr, Y). The H 2 -TPR measurements showed that the ultrafine Ce-based oxide nanoparticles with the doping-Zr cation could be favorable for improving the redox property of the catalysts.