Fast charge separation from synergistic effect of plasma Bi metal and BiOCl/SrTiO3 S-scheme heterojunction promotes NO deep removal

Abstract

The catalytic conversion of nitrogen oxides (NO_x) to non-toxic products has emerged as a critical strategy for air pollution control under stringent emission regulations. Photocatalytic NO_x removal performance highly depends on the transmission of photogenerated electrons and the amount of reactive oxygen species (ROS) generated. Herein, the Bi/BiOCl/SrTiO₃ heterostructure photocatalyst was prepared by a simple in situ synthesis method to address the limitations of conventional NOx removal systems. Due to the synergistic effect of bismuth (Bi) surface plasmon resonance (SPR) and the built-in electric field in BiOCl/SrTiO₃ S-scheme heterojunction, Bi/BiOCl/SrTiO₃ showed strong light absorption ability and high charge separation efficiency, with the highest NO removal efficiency reaching 70 %. The enhanced electronic interaction between Bi and BiOCl/SrTiO₃ induced Bi-O covalent bonds with the BiOCl layer to facilitate fast charge separation, promoting the rapid transfer of interfacial photogenerated carriers, this process induces the activation of O₂ and H₂O to form reactive oxygen species (ROS) to promote the oxidative removal of NO. This study provides new insights into the development of effective photocatalysts with fast charge separation by synergistic metal active sites and built-in electric field of heterojunction for air pollutant purification.