Faster Electron Injection and More Active Sites for Efficient Photocatalytic H2 Evolution in g‐C3N4/MoS2 Hybrid

Abstract Herein, the structural effect of MoS 2 as a cocatalyst of photocatalytic H 2 generation activity of g‐C 3 N 4 under visible light irradiation is studied. By using single‐particle photoluminescence (PL) and femtosecond time‐resolved transient absorption spectroscopies, charge transfer kinetics between g‐C 3 N 4 and two kinds of nanostructured MoS 2 (nanodot and monolayer) are systematically investigated. Single‐particle PL results show the emission of g‐C 3 N 4 is quenched by MoS 2 nanodots more effectively than MoS 2 monolayers. Electron injection rate and efficiency of g‐C 3 N 4 /MoS 2 ‐nanodot hybrid are calculated to be 5.96 × 10 9 s −1 and 73.3%, respectively, from transient absorption spectral measurement, which are 4.8 times faster and 2.0 times higher than those of g‐C 3 N 4 /MoS 2 ‐monolayer hybrid. Stronger intimate junction between MoS 2 nanodots and g‐C 3 N 4 is suggested to be responsible for faster and more efficient electron injection. In addition, more unsaturated terminal sulfur atoms can serve as the active site in MoS 2 nanodot compared with MoS 2 monolayer. Therefore, g‐C 3 N 4 /MoS 2 nanodot exhibits a 7.9 times higher photocatalytic activity for H 2 evolution (660 µmol g− 1 h −1 ) than g‐C 3 N 4 /MoS 2 monolayer (83.8 µmol g −1 h −1 ). This work provides deep insight into charge transfer between g‐C 3 N 4 and nanostructured MoS 2 cocatalysts, which can open a new avenue for more rationally designing MoS 2 ‐based catalysts for H 2 evolution.