Synergistic co-catalyst strategies for photo-thermal CO₂ reduction into value-added fuels: A critical review on mechanisms, challenges, and future prospects

Converting carbon dioxide (CO₂) into valuable chemicals and fuels using solar energy remains a crucial process for enterprises dedicated to reduce the greenhouse gas (GHG) emissions. However, the currently utilized systems offer unsatisfactory efficiency due to high energy consumption and catalyst deactivation. To address these issues a co-catalyst photo-thermal reduction of CO₂ can be adopted for large-scale implementation. This occurs as a result of light incident lowering thermal reaction's energy barrier and producing mild reaction kinetics. In conversion of CO₂, photothermal synthesis with a robust and inexpensive catalyst is crucial. It has been seen recently the significant advancements with a comprehensive approach of co-catalyst mechanism of reaction of photothermal, structure–activity relationship, control, monitoring, and regulation of co-catalyst photo-thermal composition and structure. The essential operating concept of reducing CO₂ using co-catalyst photo-thermal mechanism and CO₂ hydrogenation reaction pathways are covered and discussed in detail. The discussion of co-catalyst photo-thermal mechanism, therefore includes a range of co-catalysts, such as metals, metal-nitrides, metal-phosphides, metal-sulfides, metal-oxides, Layered double hydroxides (LDH) and their derivatives, and metal-carbides. Additionally, a summarized discussion on the co-catalyst photo-thermal process for CO₂ reduction is also provided. This process includes hydrogenating CO₂ into methane, methanol, hydrocarbons, dry reforming methane with CO₂, dehydrogenating CO₂ aided ethane, propane (hydrocarbons) and splitting CO₂ by thermochemistry. This review also discusses the viewpoints and difficulties of converting CO₂ using a co-catalyzed photo-thermal reduction technique. This review's primary goal is to provide a detailed description of the co-catalyst photo-thermal catalyst's design, the process by which CO₂ reduction occurs, and the applications of co-catalyst transformation of technology.