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Metal halide perovskites, such as iodine methylamine lead (MAPbI3), have received extensive attention in the field of photocatalytic decomposition of HI for hydrogen evolution, due to their excellent photoelectric properties. In this paper, a new MAPbI3-based composite, MoC/MAPbI3, was synthesized. The results show that 15 wt% MoC/MAPbI3 has the best hydrogen production performance (38.4 μmol h−1), which is approximately 24-times that of pure MAPbI3 (1.61 μmol h−1). With the extension of the catalytic time, the hydrogen production rate of MoC/MAPbI3 reached 165.3 μmol h−1 after 16 h due to the effective separation and transfer of charge carriers between MoC and MAPbI3, showing excellent hydrogen evolution rate performance under visible light. In addition, the cycling stability of MoC/MAPbI3 did not decrease in multiple 4 h cycle tests. This study used the non-precious metal promoter MoC to modify MAPbI3, and provides a new idea for the synthesis of efficient MAPbI3-based composite catalysts. [ABSTRACT FROM AUTHOR]

Reasonable design of heterojunction photocatalysts can effectively promote charge separation, thus improving their photocatalytic performance. Herein, a Bi2Fe4O9@ZnIn2S4 S-scheme laminated heterojunction photocatalyst with 2D/2D interface interaction is prepared via a hydrothermal–annealing–hydrothermal method. The photocatalytic hydrogen production rate of Bi2Fe4O9@ZnIn2S4 is up to 3964.26 μmol h−1 g−1, which is 12.1 times higher than that of pristine ZnIn2S4. In addition, its photocatalytic tetracycline degradation efficiency (99.9%) is also optimized. The enhanced photocatalytic performance can be attributed to the formation of S-scheme laminated heterojunctions that facilitate charge separation as well as strong 2D/2D laminated interface interactions favoring charge transfer. By combining in situ irradiation X-ray photoelectron spectroscopy with other characterization methods, the photoexcited charge transfer mechanism of S-scheme heterojunctions has been proved. Photoelectric chemical tests demonstrate the effectiveness of the S-scheme laminated heterojunction in improving the charge separation. This strategy provides a novel perspective for designing other high-efficient S-scheme laminated heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

Developing high-performance and low-cost self-supporting electrodes as pH-universal electrocatalysts for the hydrogen-evolution reaction (HER) and realizing high-quality hydrogen production at a high current density are highly desirable, but are hugely challenging. We created a self-supporting electrode with a coupled hierarchical heterostructure by simple electrodeposition followed by sulfurization. It comprised oxygen-deficient molybdenum oxide (MoO3−x) and cobalt phosphide (CoP) on nickel foam (NF), which represented a highly active pH-universal electrocatalyst for the HER at a high current density. Benefiting from a plethora of catalytic active sites, improved interfacial charge transfer, and strong electronic interaction, this type of MoO3−x@CoP/NF electrode delivered a superior catalytic performance. Overpotentials of only 100 mV, 135 mV, and 400 mV were needed to realize a high current density of 1 A cm−2 in alkaline, acid and neutral media, respectively, which were superior to those of most other well-developed materials based on non-noble metals. Our experimental work demonstrates the synergistic advantages of a MoO3−x@CoP heterostructure for improving the intrinsic catalytic performance but also paves a new path for the rational design of advanced electrodes for hydrogen generation in a wide range of pH conditions. [ABSTRACT FROM AUTHOR]

A facile synthetic route, by using rhombic dodecahedral zeolitic imidazolate framework-8 (ZIF-8) as the structure template, is devoted to fabricating the ZnS/ZnIn2S4 hybrid heterojunction; the compact heterostructure was produced by combining the sulfurization of ZIF-8 and the in situ precipitation of ZnIn2S4 in one pot. The resulting ZnS nanoparticles of about 100 nm were uniformly dispersed in the folds of flower-like ZnIn2S4, whose structure is beneficial for charge transfer at the heterointerface. The additional quantities of ZIF-8 are varied to find an optimum ratio of the two components to obtain the best photocatalytic activity. In the photocatalytic hydrogen generation irradiated by simulated solar light, all the ZnS/ZnIn2S4 hybrid photocatalysts displayed improved hydrogen production rates compared to single ZnS or ZnIn2S4, and the best hydrogen production rate of 453.4 μmol h−1 g−1 is obtained by ZnS/ZIS-20, whose value is approximately 4 times higher than that of single ZnIn2S4. The electrochemical properties of the ZnS/ZnIn2S4 hybrid photocatalysts were measured to explore the charge transfer mode at the interface, and the band structure and enhanced photocatalytic hydrogen generation mechanism have been proposed. The excellent recycling properties of hydrogen production indicated the prospective applications of this kind of ZIF-derived metal sulfide in photocatalytic reactions. [ABSTRACT FROM AUTHOR]