Hot-electron-assisted S-scheme heterojunction of tungsten oxide/graphitic carbon nitride for broad-spectrum photocatalytic H2 generation

Abstract

Extended light absorption and dynamic charge separation are vital factors that determine the effectiveness of photocatalysts. In this study, a nonmetallic plasmonic S-scheme photocatalyst was fabricated by loading 1D plasmonic W18O49 nanowires onto 2D g-C3N4 nanosheets. W18O49 nanowires play the dual role of a light absorption antenna—that extends light adsorption—and a hot electron donor—that assists the water reduction reaction in a wider light spectrum range. Moreover, S-scheme charge transfer resulting from the matching bandgaps of W18O49 and g-C3N4 can lead to strong redox capability and high migration speed of the photoinduced charges. Consequently, in this study, W18O49/g-C3N4 hybrids exhibited higher photocatalytic H2 generation than that of pristine g-C3N4 under light irradiation of 420–550 nm. Furthermore, the H2 production rate of the best-performing W18O49/g-C3N4 hybrid was 41.5 μmol·g−1·h−1 upon exposure to monochromatic light at 550 nm, whereas pure g-C3N4 showed negligible activity. This study promotes novel and environmentally friendly hot-electron-assisted S-scheme photocatalysts for the broad-spectrum utilization of solar light.