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Titanium carbide (Ti3C2) MXenes due to their structural and optical characteristics rapidly emerged as the preferred material, particularly in catalysis and energy applications. On the other hand, because of its enormous surface/volume ratio and porosity, Metal-organic Frameworks (MOFs) show promise in several areas, including catalysis, delivery, and storage. The potential to increase the applicability of these magic compounds might be achieved by taking advantage of the inherent flexibility in design and synthesis, and optical characteristics of MXenes. Thus, coupling MOF with Ti3C2 MXenes to construct hybrid composites is considered promising in a variety of applications, including energy conversion and storage. This paper presents a systematic discussion of current developments in Ti3C2 MXenes/MOF composites for photocatalytic reduction of CO2, and production of hydrogen through water splitting. Initially, the overview and characteristics of MXenes and MOFs are independently discussed and then a detailed investigation of efficiency enhancement is examined. Different strategies such as engineering aspects, construction of binary and ternary composites and their efficiency enhancement mechanism are deliberated. Finally, different strategies to explore further in various other applications are suggested. Although Ti3C2 MXenes/MOF composites have not yet been thoroughly investigated, they are potential photocatalysts for the production of solar fuel and ought to be looked into further for a range of applications. [ABSTRACT FROM AUTHOR]

Highly reducible Ni/TiO2 modified ZnTiO3 composite was synthesized through hydrothermal approach and tested through phenol steam reforming (PSR) for hydrogen production. The activity tests were conducted in a continuous flow reactor to determine the effect of bi metal modified ZnTiO3 support on PSR reaction. Ni/TiO2 modified ZnTiO3 composite is a promising reforming catalyst for H2 production and can be further employed in cleaner energy production and other environmental applications.

Greenhouse gas CO2 emitted through the burning of fossil fuels is a main cause of global warming.Using BRM process, production of CO was further increased due to the addition of water into CO2-methane system. In general, significantly enhanced photocatalytic performance of composite catalyst was obviously due to Z-scheme heterojunction formation with efficient charge carrier separation and good band positions under visible light irradiation. The newly developed composite catalysts can effectively be used for recycling greenhouse gases to fuels using solar energy and would be beneficial for cleaner environment.

Summary: Photocatalysis of carbon dioxide by the assistance of solar energy has been one of the most promising approaches to reduce CO2 to renewable fuel. Several methods are pertained to enhance the photocatalytic activity for stimulating CO2 reduction to selective fuels. Even though many researchers have been exploring methods of assembling a suitable semiconductor, practical constraints such as charge carrier recombination and low light utilization limit the photocatalytic activity. In this review, recent advancement in semiconductors and their characteristics toward the photoreduction of CO2 has been comprehensively discussed. The major semiconductors that are discussed and analyzed based on their limitations in this review are TiO2, BiVO4, CdS, g‐C3N4, ZnO, and MoS2‐based composites. Initially, the fundamentals of heterogeneous photocatalysis such as the possible molecular pathways, product selectivity, and thermodynamics have been deliberated. Advancement in semiconductors in relation to quantum dots, heterojunction, and sacrificial reagent has been systematically analyzed. Doping and co‐doping of semiconductors have proven to reduce the band gap notably and its outstanding electronic band position for the visible light photocatalysis has been identified. Furthermore, the developments of cocatalysts such as noble metals and nonmetals to stimulate photocatalysts performance in view of CO2 reduction to value‐added products have been disclosed. Specific developments in binary semiconductors through Z‐scheme, S‐scheme, and ternary heterojunction for charge separation and their characterization has been thoroughly deliberated. In addition, the role of doping, structural defects, as well as sensitization in enhancing the light harvesting abilities of the photocatalyst has been discoursed. The developments in photocatalytic reactors with their characteristics and limitations are also assiduously discussed. Finally, conclusions and future directions for photocatalysis of carbon dioxide toward renewable fuel production have been suggested. [ABSTRACT FROM AUTHOR]