Dual defects and build-in electric field mediated direct Z-scheme W18O49/g-C3N4−x heterojunction for photocatalytic NO removal and organic pollutant degradation

Abstract

In this work, dual defects mediated W18O49/g-C3N4−x heterojunction was prepared by in-situ hydrothermal method. The conversion from Ⅱ-type to Z-scheme heterojunction was achieved due to the formation of build-in electric field from g-C3N4−x to W18O49. Tests results indicated that the LSPR hot electrons of W18O49 could directly drive oxygen reduction reaction to generate O2− species and the partial electrons of g-C3N4−x were captured by O defect states of W18O49 to stabilize its free charge density, resulting in the continuous generation of high-energy hot electrons. The photo-generated carriers had the stronger redox ability compared with g-C3N4−x and W18O49 due to the Z-scheme charge transfer paths. Combined with the promoted exciton dissociation induced by N vacancies, the enhanced light absorption and accelerated carriers’ separation induced by near-field enhancement effect in visible-NIR range of oxygen vacancies, W18O49/g-C3N4−x heterojunction exhibited enhanced photocatalytic performance for NO removal and full-solar-spectrum-driven pollutants degradation.