Highly selective and efficient photocatalytic NO removal: Charge carrier kinetics and interface molecular process

The widespread nitrogen oxides (NO_x, mainly in NO) in the atmosphere have threatened human health and ecological environment. The dilute NO (ppb) is difficult to efficiently remove via the traditional process due to its characteristics of low concentration, wide range, large total amount, etc. Photocatalysis can utilize solar energy to purify NO pollutants under mild conditions, but its application is limited due to the low selectivity of nitrate and poor activity of NO removal. The underlying reason is that the interface mechanism of NO oxidation is not clearly understood, which leads to the inability to accurately regulate the NO oxidation process. Herein, the recent advances in the photocatalytic oxidation of NO are summarized. Firstly, the common strategies to effectively regulate carrier dynamics such as morphology control, facet engineering, defect engineering, plasma coupling, heterojunction and single-atom catalysts are discussed. Secondly, the progress of enhancing the adsorption and activation of reactants such as NO and O₂ during NO oxidation is described in detail, and the corresponding NO oxidation mechanisms are enumerated. Finally, the challenges and prospects of photocatalytic NO oxidation are presented in term of nanotechnology for air pollution control. This review can shed light on the interface mechanism of NO oxidation and provide illuminating information on designing novel catalysts for efficient NO_x control.