Emergence of CuInS2 derived photocatalyst for environmental remediation and energy conversion

Hydrogen production, catalytic organic synthesis, carbon dioxide reduction, environmental purification, and other major fields have all adopted photocatalytic technologies due to their eco-friendliness, ease of use, and reliance on sunlight as the driving force. Photocatalyst is the key component of photocatalytic technology. Thus, it is of utmost importance to produce highly efficient, stable, visible-light-responsive photocatalysts. CIS stands out among other visible-light-response photocatalysts for its advantageous combination of easy synthesis, non-toxicity, high stability, and suitable band structure. In this study, we took a brief glance at the synthesis techniques for CIS after providing a quick introduction to the fundamental semiconductor features, including the crystal and band structures of CIS. Then, we discussed the ways doping, heterojunction creation, p-n heterojunction, type-II heterojunction, and Z-scheme may be used to modify CIS's performance. Subsequently, the applications of CIS towards pollutant degradation, CO2 reduction, water splitting, and other toxic pollutants remediation are reviewed in detail. Finally, several remaining problems with CIS-based photocatalysts are highlighted, along with future potential for constructing more superior photocatalysts.

Prominent roles of Ni(OH)2 deposited on ZnIn2S4 microspheres in efficient charge separation and photocatalytic H2 evolution

In this work, Ni(OH)₂-deposited ZnIn₂S₄ microspheres (Ni(OH)₂/ZnIn₂S₄) were fabricated using a hydrothermal process, followed by a facile in situ precipitation method. It was demonstrated that the deposition of Ni(OH)₂ on ZnIn₂S₄ effectively promotes the separation of charges photogenerated over ZnIn₂S₄, and significantly enhances photocatalytic H₂ evolution. The optimum rate of the photocatalytic H₂ evolution over the 6% Ni(OH)₂/ZnIn₂S₄ composite reaches 4.43 mmol g⁻¹ h⁻¹, which is 21.1 times higher than that of the pure ZnIn₂S₄. Based on various characterization results and Au photo-deposition on the composite, it was proposed that the capture of the photogenerated holes by the deposited Ni(OH)₂ would be responsible for the efficient charge separation, which allows more photogenerated electrons to be left on the ZnIn₂S₄ for the reduction of H⁺ to H₂ with a higher rate.

The capture of the photogenerated holes by the deposited Ni(OH)₂ contributes to the efficient charge separation, allowing more photogenerated electrons to be left on ZnIn₂S₄ to reduce H⁺ to H₂.

Improvement of the Photocatalytic Activity of ZnO/Burkeite Heterostructure Prepared by Combustion Method

In this work, a novel route is discussed to produce in one step ZnO/Burkeite powders by the modified solution combustion method. The ZnO particles enhance the photocatalytic activity in the degradation of Rhodamine B, in which Burkeite mineral acts as a support due to the pH-dependent morphology of the particle aggregates of the as-synthesized powders. The X-ray diffraction (XRD) characterization shows the presence of a heterostructure: ZnO/Burkeite. The Scanning Electron Microscopy (SEM) image shows a morphological dependence with the pH of the solution used for the synthesis. The results show that the system with the highest degradation (92.4%) corresponds to the case in which ZnO/Burkeite heterostructure was synthesized with a pH 11.