Mechanistic Investigation of Alkali‐Treated Photocatalytic CO2 Reduction: The Role of OH− and Metal Cations for Almost 100 % Selectivity of CO.

In this work, the modulation of activity and selectivity via photoreduction of carbon dioxide under simulated sunlight was achieved by treating P25 and P25/Pt NPs with KOH. It found that KOH treatment could significantly improve the overall conversion efficiency and switch the selectivity for CO. Photoelectric characterizations and CO2‐TPD demonstrated that the synergistic effect of K+ and OH‐ accelerated the separation and migration of photogenerated charges, and also improved CO2 adsorption level. Significantly, the K ions could act as active sites for CO2 adsorption and further activation. In situ FTIR measurements and DFT calculations confirmed that K+ enhanced the charge density of adjacent atoms and stabilize CO* groups, reducing the reaction energy barrier and inducing the switching of original CH4 to CO, which played a selective regulatory role. This study provides insights into the photocatalytic activity and selectivity of alkali‐treated photocatalysts and facilitates the design of efficient and product‐specific photocatalysis. [ABSTRACT FROM AUTHOR]