Enhancing photocatalytic CO reduction with TiO-based materials: Strategies, mechanisms, challenges, and perspectives.

The concentration of atmospheric CO has exceeded 400 ppm, surpassing its natural variability and raising concerns about uncontrollable shifts in the carbon cycle, leading to significant climate and environmental impacts. A promising method to balance carbon levels and mitigate atmospheric CO rise is through photocatalytic CO reduction. Titanium dioxide (TiO), renowned for its affordability, stability, availability, and eco-friendliness, stands out as an exemplary catalyst in photocatalytic CO reduction. Various strategies have been proposed to modify TiO for photocatalytic CO reduction and improve catalytic activity and product selectivity. However, few studies have systematically summarized these strategies and analyzed their advantages, disadvantages, and current progress. Here, we comprehensively review recent advancements in TiO engineering, focusing on crystal engineering, interface design, and reactive site construction to enhance photocatalytic efficiency and product selectivity. We discuss how modifications in TiO's optical characteristics, carrier migration, and active site design have led to varied and selective CO reduction products. These enhancements are thoroughly analyzed through experimental data and theoretical calculations. Additionally, we identify current challenges and suggest future research directions, emphasizing the role of TiO-based materials in understanding photocatalytic CO reduction mechanisms and in designing effective catalysts. This review is expected to contribute to the global pursuit of carbon neutrality by providing foundational insights into the mechanisms of photocatalytic CO reduction with TiO-based materials and guiding the development of efficient photocatalysts.