Insights into photocatalytic CO 2 reduction reaction pathway: Catalytic modification for enhanced solar fuel production

Over the decades, one of the best ways to prevent environmental deterioration and the global energy crisis is to convert carbon dioxide (CO 2 ) into chemical fuels by utilizing different pathways such as photoreduction, electroreduction, or thermo-reduction pathways. Researchers have intrigued to find out that under realistic working conditions, the associated catalysts may undergo constant reconstruction, which, regrettably, leads to conflicting findings about the active sites and reaction mechanism of CO 2 reduction. Therefore, employing in situ techniques to monitor the dynamic growth of catalysts and reaction intermediates in real time is essential, although it presents significant challenges. Herein this review, we have addressed the comprehensions into one of the widely accepted in situ techniques which is photocatalytic reduction pathway of capturing and reducing CO 2 gas into hydrocarbon solar fuels. However, the practical implication of photocatalytic CO 2 reduction is somehow constrained by its low activity and poor product selectivity. Hence, it is highly mandatory to understand the photocatalyst selection, catalytic modulation, and band gap tuning to enhance the kinetics, specificity, and selectivity of the target hydrocarbon product. Therefore, we have provided several insights on how to tune a photocatalyst to make it fit for the better CO 2 capture and reduction into selective hydrocarbon fuels. Along with catalyst modulation strategies, we have also focused on the photocatalyst listings which are non-titanium based, as we face several restraints related to titanium. In conclusion, the present situation, obstacles, and future outlook in creating photocatalysts with elevated CO 2 reduction efficiency and substantial product yield are highlighted and explored.