Defects and internal electric fields synergistically optimized g-CN/BiOCl/WO heterojunction for photocatalytic NO deep oxidation.

In this work, g-CN/BiOCl/WO heterojunction with "N-O" vacancies was prepared using NaBiO and WCl as raw materials and non-metal plasma of WO grew in-situ on the surface of BiOCl, resulting in the enhanced photocatalytic NO deep oxidation. XPS tests and DFT calculation indicated the formation of internal electric fields from g-CN to BiOCl, BiOCl to WO, which induced the transition from Ⅱ-Ⅱ-type to double Z-scheme hetero-structure. High separation efficiency, prolong lifetime and strong redox ability of photo-generated electron-hole pairs were simultaneously achieved due to the charge capture effect of defects and double Z-scheme mechanism. Therefore, g-CN/BiOCl/WO exhibited the significantly increased NO removal rates from 21.17% (BiOCl/WO) and 36.52% (g-CN) to 68.70% and the main oxidation product of NO was NO. This study revealed that the carrier dynamics of heterojunction photocatalysts could be optimized by the synergistic effect of defects and internal electric fields to achieve photocatalytic NO deep oxidization.