Photocatalytic NOx abatement: Recent advances and emerging trends in the development of photocatalysts

The abatement of NOx emission, which is one of the most critical global environmental issues, is traditionally addressed using risky and costly approaches that require high reaction temperatures. To counter this drawback, much attention has been directed at the development of photocatalytic NOx abatement techniques, including photocatalytic oxidation, photocatalytic decomposition, and photoselective catalytic reduction (photo-SCR), as they allow one to reduce the reaction temperature and increase conversion efficiency. Therefore, photocatalyst design is of crucial importance for the development of next-generation NOx abatement technologies. This review rationally summarizes and discusses recent progress in photocatalytic NOx abatement, highlighting catalyst type, removal pathway, and parameters governing the removal efficiency for each approach as well as considering strategies for the advancement of photocatalysts featuring high catalytic activities at low reaction temperatures for each process. Finally, the remaining challenges obstacles and directions for the future development of photocatalytic NOx abatement are provided. (C) 2020 Elsevier Ltd. All rights reserved.