Search

Exploiting efficient and stable photocatalysts is the primary goal of photocatalytic water splitting for H2 production. In this work, a sea urchin-like bimetallic NiCo2O4-decorated ZnIn2S4 heterojunction was fabricated via a solvent evaporation method. Investigation shows that the introduction NiCo2O4 can expand the UV-vis absorption range, enhance the absorption intensity, promote the charge separation, decrease the charge transfer resistance, induce more active sites, and decrease the H2 evolution overpotential of the composite. Besides, the charge transfer between NiCo2O4 and ZnIn2S4 follows a Z-scheme route based on the ˙OH radical capture experiments; this can preserve the strong oxidation–reduction reaction ability of photogenerated electrons and holes, leading to a faster H2 evolution rate, which reaches 17.28 mmol g−1 h−1 over the 4.8%-NiCo2O4/ZnIn2S4 composite under 300 W Xe lamp irradiation in 20 vol% triethanolamine (TEOA) solution and is 3.0 times higher than that of ZnIn2S4. In addition, NiCo2O4/ZnIn2S4 also has excellent stability during 5 consecutive cycles. This work provides an effective method for constructing a highly effective Z-scheme heterojunction system for photocatalytic H2 production. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered heterostructures have attracted substantial attention in recent years as promising platforms for the direct conversion of renewable solar energy to chemical fuels due to their unique optoelectronic, transport, and interfacial properties. The rational structural design and tailored synthesis of semiconductor heterojunctions are critical to explore and achieve well-defined photocatalytic systems. Herein, we propose a design strategy for ultrathin 2D FeS–FeSe2 lateral heterostructures to achieve rapid spatial migration of photogenerated charge carriers and to facilitate favorable kinetics of target surface redox reactions for photocatalysis. The resultant composites have superior photocatalytic H2 generation activity (2071.1 μmol g−1 h−1) without any noble metal as a cocatalyst under sunlight and show marked photocatalytic durability after a continuous test for 20 h under alkaline conditions. In particular, we have found, for the first time, that the irradiated FeS–FeSe2 is active for producing H2O2 by the two-electron reduction of O2 in the photocatalytic degradation process of phenol solution. A series of mechanistic studies on photocatalysis clearly demonstrates that the pronounced photocatalytic performance of the 2D lateral heterojunction nanosheets could be a result of increased carrier density, longer electron lifetime and higher hole injection efficiency as well as a stepwise two-electron/two-step reduction pathway. [ABSTRACT FROM AUTHOR]

In this study, a carbon membrane-mediated CdSe and TiO 2 ternary film (CdSe/C/TiO 2 ) was prepared to degrade methylene blue (MB). Carbon membrane and CdSe were introduced to the surface of a TiO 2 nanofiber film via an in situ hydrothermal deposition process successively. The investigation shows that the carbon membrane not only provides a charge transfer channel to promote the transfer of electron from the conduction band of CdSe to that of TiO 2 , but also improves the poor conduct between the TiO 2 film and electrolyte. The synergies between the carbon membrane and CdSe can make the ternary system harvest more visible light energy and facilitate the charge transfer property of TiO 2 . The current density of CdSe/C/TiO 2 was about 9 folds higher compared with that of pure TiO 2 under UV and visible light irradiations. This ternary hybrid exhibits a superior activity during the photoelectrochemical (PEC) degradation of MB, and 92.43% can be removed after 120 min irradiation, which is improved by 21.14% than that of TiO 2 ., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Although photocatalysis is frequently employed to remove various pollutants in water, it still suffers from low efficiency due to the rapid recombination of photogenerated electrons and holes. In this study, a red phosphorus/tin disulfide (RP/SnS 2 ) composite photocatalyst is fabricated by loading nano-sized RP on flower-like SnS 2 films with a facile hydrothermal method. It is noteworthy that the 2D heterojunction formed between SnS 2 and RP provided channels for the rapid transfer of photon-generated carriers and their effective separation. Furthermore, the separated electrons can react with absorbed O 2 for the generation of superoxide radicals (˙O 2 - ), thereby impacting the photocatalytic degradation oxidation reaction. The application of photocatalytic synchronous removal of Cr(vi) and RhB over RP/SnS 2 was implemented first. Compared with pristine SnS 2 , the photocatalytic degradation activity of Cr(vi) and RhB over the RP/SnS 2 composite was significantly enhanced and the kinetic rate constant reached 8.2, which is 10.8 times that of pristine SnS 2 . Moreover, the hybrid photocatalysts exhibited prominent reusability and stability. Therefore, a photocatalytic degradation mechanism and pathway of carriers are proposed in the study. Furthermore, it is considered that the present study is a promising method in the treatment of wastewater by photocatalysis., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)