Synergistic charge transfer on n-WO3/p-WS2/Au ternary heterojunction material for solar energy-driven sustainable H2 production

This study investigated the effects of changes in charge transport and photo-quantity on photocatalytic water splitting by a new ternary heterojunction with the structure n-WO3/p-WS2/Au, in which gold (Au), an electron transport medium, was inserted between negative (n)-type tungsten oxide (WO3) plates and a positive (p)-type tungsten sulfide (WS2) sheet. When two particles (n-WO3 and p-WS2) were used in-dividually as catalysts, no water splitting occurred, even after a sufficient lapse of time. However, the de-composition of methyl orange on the n-WO3 single particle and the reduction of Ag+ ions on the p-WS2 single particle occurred favorably. In contrast to the single particle results, with the n-WO3/p-WS2 het-erojunction particle, hydrogen was generated at 10.30 mu mol g-1 h-1 by water splitting, and with the n-WO3/ p-WS2/Au ternary heterojunction particle, more than double this amount of hydrogen was generated. A lower photoluminescence intensity, higher photocurrent density, longer electron/hole recombination time, and faster electron transport rates were possible with the ternary heterojunction particle. The interparticle junction resulted in synergy in the photochemical properties, with the formation of effective redox reaction sites. In particular, the loaded Au acted as an electron trapper that attracted electrons, rather than the surface plasmon resonance effect, thereby expanding the sites for reduction reactions in the particle and improving hydrogen generation. Eventually, it was found that the charge transfer on the n-WO3/p-WS2/Au ternary heterojunction particles progressed by an M-scheme. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the effects of changes in charge transport and photo-quantity on photocatalytic water splitting using a new ternary heterojunction n-WO3/p-WS2/Au. The results show that the ternary heterojunction particles exhibit improved photochemical properties and can generate more hydrogen compared to single particles. The loaded Au acts as an electron trapper, expanding the reduction reaction sites and enhancing hydrogen generation.