The use of solar energy to catalyze the photo-driven processes has attracted tremendous attention from the scientific community because of its great potential to address energy and environmental issues. In this regard, several attempts have been made by researchers to design and develop different materials with enhanced photocatalytic efficiencies. This Review comprehensively summarizes the recent reports on perovskite oxide based photocatalysts for organic pollutant degradation, water splitting, carbon dioxide conversion, and nitrogen fixation along with the basic understanding of involved mechanisms, current trends and advances in the field. The different design, synthesis, and development strategies have been discussed in detail to provide a comprehensive view of materials’ fabrication that influences their photocatalytic properties. Subsequently, the insights from recent reports on different perovskite oxide based materials, including simple oxides, mixed oxides, and layered perovskite oxides, are provided for the above-mentioned photocatalytic applications in a detailed manner. Finally, a summary of photocatalytic applications and a perspective on future research direction have been discussed. Based on the research progress in this field, it is highly anticipated that the photocatalytic systems, comprising perovskite oxide materials along with groundbreaking technologies for large-scale realization of these processes, can be established in the near future to address the energy and environment-oriented challenges.

Scheme 1. Different strategies and concepts employed in the design and development of photocatalysts based on a semiconductor, such as TiO 2 , and plasmonic NPs.

The development of noble metal-free catalysts for hydrogen evolution is required for energy applications. In this regard, ternary heterojunction nanocomposites consisting of ZnO nanoparticles anchored on MoS -RGO (RGO=reduced graphene oxide) nanosheets as heterogeneous catalysts show highly efficient photocatalytic H evolution. In the photocatalytic process, the catalyst dispersed in an electrolytic solution (S and SO ions) exhibits an enhanced rate of H evolution, and optimization experiments reveal that ZnO with 4.0 wt % of MoS -RGO nanosheets gives the highest photocatalytic H production of 28.616 mmol h g under sunlight irradiation; approximately 56 times higher than that on bare ZnO and several times higher than those of other ternary photocatalysts. The superior catalytic activity can be attributed to the in situ generation of ZnS, which leads to improved interfacial charge transfer to the MoS cocatalyst and RGO, which has plenty of active sites available for photocatalytic reactions. Recycling experiments also proved the stability of the optimized photocatalyst. In addition, the ternary nanocomposite displayed multifunctional properties for hydrogen evolution activity under electrocatalytic and photoelectrocatalytic conditions owing to the high electrode-electrolyte contact area. Thus, the present work provides very useful insights for the development of inexpensive, multifunctional catalysts without noble metal loading to achieve a high rate of H generation.

Novel RGO–NCT composites have been synthesized and utilized for the degradation of MB and TBZ, as efficient bifunctional adsorptive photocatalysts.

Molybdenum disulfide has emerged as one of the promising materials, particularly as a co-catalyst for photocatalytic hydrogen evolution over the conventional and more-expensive platinum. Herein, we report novel onedimensional/two-dimensional (1D-2D) heterostructures consisting of nitrogen-doped ZnO nanorods coated with defect-rich MoS 2 nanosheets having abundant edge sulfur atoms. The optimized heterostructure consists of 15 wt % of defect-rich MoS 2 nanosheets-coated on N-ZnO showed the highest H 2 evolution of 17.3 mmol h −1 g cat −1 under solar light irradiation. The improved photocatalytic H 2 evolution can be attributed to (i) the in-situ-generated ZnS during the process, which increased the number of interfaces, (ii) the presence of abundant exposed sulfur edge atoms in defect-rich MoS 2 nanosheets, which has strong affinity for H + ions, and (iii) the intimate heterojunction formed between N-ZnO and MoS 2 , which facilitates charge transfer efficiency. Hence, this work offers a promising strategy for the design and development of defect engineered heterostructure photocatalysts for greatly enhanced solar-to-fuel conversion.