Recent Advances on the Utilization of TiO₂-Based Catalysts in the Photocatalytic Reduction of CO₂ to Methane

Addressing the escalating concerns over increasing carbon dioxide (CO2) emissions and their detrimental effect on the environment has become global attention. One promising alternative to tackle this issue involves utilizing photocatalytic technology to convert CO2 into more valuable chemicals, with methane (CH4) being a notable targeted product. This article presents a comprehensive review of the exploration of TiO2-based photocatalysts by researchers worldwide for such applications. The initial discussion revolves around fundamental aspects, including the basic principles, thermodynamics, kinetics, and reaction mechanisms involved in the process. Additionally, to enhance the efficiency of these aspects, support from other factors is necessary, including the physicochemical properties of the photocatalyst through various catalyst synthesis methods (such as sol-gel, precipitation, hydrothermal, and solvothermal) as well as employing catalyst modification techniques (such as doping, heterojunction, and surface modifications). Furthermore, the review delves into an examination of parameters that influence the photocatalytic CO2 reduction to methane process, as they directly impact the yield and selectivity of the desired product. Ultimately, the existing challenges and potential research opportunities that could provide comprehensive solutions for the applications of photocatalytic technology for converting CO2 to CH4 as a whole are elaborated in this review.