Co doped MoS2 as cocatalyst considerably improved photocatalytic hydrogen evolution of g-C3N4 in an alkalescent environment

( )The Gibbs free energy of MoS2 for H+ absorption is near-zero, which is considered to be a promising cocatalyst for H-2 production. Nevertheless, the activity of MoS2 for HER is greatly limited by the acidic environment. Herein, we study that Co-doped MoS2 (Co-MoS2) nanosheets can realize an extremely efficient photocatalytic H-2 production of g-C3N4 nanosheet (NSs) in alkalescent environment, such as triethanolamine (TEOA). The optimized Co-MoS2/g-C3N4 hybrids exhibits extremely boosted photocatalytic H-2 evolution rate of 3193 mu mol(-1) h(-1) g(-1), approximately 2.4, 6.0 and 42.0 times as much as MoS2/g-C3N4 (1326 mu mol(-l )h(-1) g(-1)), CoS2/g-C3N4 (530 g(-1)) and pure g-C3N4 (76 mu mol(-l) h(-1) g(-1)), respectively. Besides, we calculated the apparent quantum efficiency (AQE) of all photocatalysts under the light at lambda = 370 nm, and the AQE of CoS2/g-C3N4 hybrids reaches 16.62%. DFT calculation and experimental data reveal that the outstanding HER activity of CoS2/g-C3N4 hybrids is ascribed to the Co doping inducing the distortion of MoS2 crystal, which effectively reduces the H binding free energy for HER. The project of CoS2/g-C3N4 hybrids provides experience on the progress of low-cost and highly effective photocatalysts for photocatalytic H-2 evolution.