Construction of 2D/2D ZnIn2S4/Nb2CTx (MXene) hybrid with hole transport highway and active facet exposure boost photocatalytic hydrogen evolution

In this study, leveraging the tunable surface groups of MXene , the two-dimensional (2D) Nb 2 C T x with OH terminal (NC) was synthesized. 2D ZnIn 2 S 4 (ZIS) nanosheets were prepared with the aid of sodium citrate, enhancing the exposure ratio of active (1   1   0) facet. On this basis, 2D/2D ZnIn 2 S 4 /Nb 2 C T x heterojunctions were fabricated to improve photocatalytic hydrogen evolution reaction (HER) performance. The optimized 6 wt%Nb 2 C T x /ZnIn 2 S 4 -450 (6NC/ZIS-450) photocatalyt exhibits a remarkable HER rate of 3603 μmol g −1 h −1 , which is 10 times superior to that of the original ZnIn 2 S 4 . Its apparent quantum efficiency (AQE) at 380 nm reaches 14.9 %. Meanwhile, even after 5 rounds of HER, the activity of 2D/2D ZnIn 2 S 4 /Nb 2 C T x heterojunction remained at 90 %, far superior to that of pure ZnIn 2 S 4 (34 % and 31 %). Energy band structure analysis and density functional theory (DFT) calculation indicate that Nb 2 C T x adsorbed with OH exhibit a low work function . By serving as a hole cocatalyst, it effectively boosts the photocatalytic HER rate of ZnIn 2 S 4 /Nb 2 C T x heterojunction and inhibits the photocorrosion of ZnIn 2 S 4 . This unique insight, via hole transport highways and increased exposure of active facets, effectively enhances the activity and stability of sulfides photocatalysts .