1T-WS2/NCN photocatalyst with unique trion behavior and cyano-defects: Photocatalytic hydrogen evolution and mechanistic insights

The interfacial catalytic reaction rate determines the hydrogen production performance of the photocatalyst. In this work, high specific surface area and cyano-defects g-C3N4 with 1T-WS2 as a co-catalyst was prepared to construct 1T-WS2/NCN photocatalytic system. The two-electron interfacial catalytic reaction pattern formed due to the unique trions behaviour of 1T-WS2 greatly enhanced the interfacial catalytic reaction rate. Under 180 min of light, the hydrogen production of the photocatalytic system could reach 5769.3 mu mol/g, which was 91.6 times that of the pristine g-C3N4. It was found that the excellent electrical conductivity of 1T-WS2 with metallic nature and the low Gibbs free energy of its active edge facilitated the hydrogen production and release. Meanwhile, the unique trions behaviour of the two-electron catalytic reaction formed in 1T-WS2 is a significant factor in increasing the rate of photocatalytic hydrogen production. And the cyano-defects in g-C3N4 acts as an electron trap, which drives charge space separation and provides sufficient electrons for trions formation, facilitating two-electron catalytic hydrogen production. This study provides a new idea for the development of electron-hole separation to improve the photocatalytic hydrogen production activity, which has important theoretical significance and application value.