In Situ Construction of Hollow Coral‐Like Porous S‐Doped g‐C3N4/ZnIn2S4 S‐Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

The rational design of visible‐light‐responsive catalysts is crucial for converting solar energy into hydrogen energy to promote sustainable energy development. In this work, a C─S─C bond is introduced into g‐C3N4 (CN) through S doping. With the help of the flexible C─S─C bond under specific stimuli, a hollow coral‐like porous structure of S‐doped g‐C3N4 (S‐CN) is synthesized for the first time. And an S‐doped g‐C3N4/ZnIn2S4 (S‐CN/ZIS) heterojunction catalyst is in situ synthesized based on S‐CN. S0.5‐CN/ZIS exhibits excellent photocatalytic hydrogen evolution (PHE) efficiency (19.25 mmol g−1 h−1), which is 2.7 times higher than that of the g‐C3N4/ZnIn2S4 (CN/ZIS) catalyst (8.46 mmol g−1 h−1), with a high surface quantum efficiency (AQE) of 34.43% at 420 nm. Experiments and theoretical calculations demonstrate that the excellent photocatalytic performance is attributed to the larger specific surface area and porosity, enhanced interfacial electric field (IEF) effect, and appropriate hydrogen adsorption Gibbs free energy (ΔGH*). The synergistic effect of S doping and S‐scheme heterojunction contributes to the above advancement. This study provides new insights and theoretical basis for the design of CN‐based photocatalysts. S‐CN/ZIS has a hollow coral‐like porous structure. ZIS uniformly grows on the surface of S‐CN to construct an S‐scheme heterojunction. Compared to CN/ZIS, S‐CN/ZIS exhibits a stronger interface electric field effect, larger specific surface area, and more suitable hydrogen adsorption and desorption energy. Therefore, S‐CN/ZIS can achieve efficient photocatalytic hydrogen evolution.