Defects and internal electric fields synergistically optimized g-C3N4−x/BiOCl/WO2.92 heterojunction for photocatalytic NO deep oxidation

In this work, g-C3N4−x/BiOCl/WO2.92 heterojunction with “N-O” vacancies was prepared using NaBiO3 and WCl6 as raw materials and non-metal plasma of WO2.92 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-C3N4−x to BiOCl, BiOCl to WO2.92, 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-C3N4−x/BiOCl/WO2.92 exhibited the significantly increased NO removal rates from 21.17% (BiOCl/WO2.92) and 36.52% (g-C3N4−x) to 68.70% and the main oxidation product of NO was NO3−. 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. [Display omitted] •g-C3N4−x/BiOCl/WO2.92 was prepared for photocatalytic NO deep oxidation.•Double Z-scheme mechanism was achieved due to the formation of internal electric fields.•Charge capture effect of “N-O” vacancies induced promoted space charge separation.•68.70% of NO was removed by g-C3N4−x/BiOCl/WO2.92 under visible light irradiation.•NO3− was the main oxidation product of photocatalytic NO removal.