A facile approach to synthesize CdS-attapulgite as a photocatalyst for reduction reactions in water

At room temperature, a facile approach has been utilized for preparing novel CdS–attapulgite (CdS–ATP) composites and the composites were applied in photocatalytic reduction of p-nitrophenol and Cr(vi). The effect of ATP on the photocatalytic activity of the CdS–ATP composites were studied by controlling the mass ratio of attapulgite. The results showed that the CdS–20%ATP composite has an excellent photocatalytic activity. In order to figure out the key to improve the photocatalytic efficiency, the prepared composites were characterized by Brunauer–Emmett–Teller (BET) specific surface area, UV-vis diffuse reflectance spectroscopy (DRS) and electrochemical impedance spectroscopy (EIS). The superior photocatalytic performance of the CdS–20%ATP composite can be ascribed to the existence of the ATP which can fix the CdS and prevent agglomeration. The interaction between ATP and CdS in the composites facilitates the electron transfer and also promoted their photocatalytic performance. This work provides us with some significant guidance in the development of CdS–ATP composite photocatalysts.

The application of CdS–attapulgite composites in photocatalytic reduction of p-nitrophenol and Cr(vi) demonstrated that the attapulgite could overcome the limitations of CdS.

Efficient thermal- and photocatalysts made of Au nanoparticles on MgAl-layered double hydroxides for energy and environmental applications

Composites of the noble metal Au supported on MgAl-LDHs were prepared by a simple impregnation-reduction method to be used as thermal- and photocatalysts for the photocatalytic degradation of ciprofloxacin and thermocatalytic decomposition of formic acid to produce hydrogen. A collection of techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to determine the structure and morphology properties of the as-prepared Au/MgAl-LDHs. The presence of surface Au(0) in Au/MgAl-LDHs was confirmed by TEM and XPS analyses. For the first time, we compared the effect of the surfactant PVP on the catalyst and found that the Au/MgAl-LDH composite with Au particle size of 2-8 nm had better catalytic activity than the (PVP@Au)/MgAl-LDH composite with Au particle size in the range of 1-5 nm. The sizes of Au NPs in the two catalysts were similar but had different effects on the catalytic performance. This indicated that the addition of PVP had an inhibitory effect on the catalytic activity of the catalyst. To evaluate the photostability of Au/MgAl-LDHs, recycle experiments for the photocatalytic degradation of ciprofloxacin were performed, and it was found that Au/MgAl-LDHs had good stability. Finally, we also applied Au/MgAl-LDHs in environmental catalysis and energy catalysis; we hope that they will be useful in practical applications.

Thermo-Photocatalysis: Environmental and Energy Applications

Catalysis is an integral part of a majority of chemical operations focused on the generation of value-added chemicals or fuels. Similarly, the extensive use of fossil-derived fuels and chemicals has led to deterioration of the environment. Catalysis currently plays a key role in mitigating such effects. Thermal catalysis and photocatalysis are two well-known catalytic approaches that were applied in both energy and environmental fields. Thermo-photocatalysis can be understood as a synergistic effect of the two catalytic processes with key importance in the use of solar energy as thermal and light source. This Review provides an update on relevant contributions about thermo-photocatalytic systems for environmental and energy applications. The reported activity data are compared with the conventional photocatalytic approach and the base of the photothermal effect is analyzed. Some of the systems based on the positive aspects of thermo- and photocatalysis could be the answer to the energy and environmental crisis when taking into account the outstanding results with regard to chemical efficiency and energy saving.