Noble-metal-free Ni3C cocatalysts decorated CdS nanosheets for high-efficiency visible-light-driven photocatalytic H2 evolution

In this work, Ni3C nanoparticles (NPs, 0 D) were for the first time used as H2-evolution cocatalysts to modify CdS nanosheets (NSs, 2 D) to achieve the high-efficiency photocatalytic H2 evolution under visible light irradiation. The photocatalytic H2-evolution activities of the Ni3C/CdS hybrid NSs were tested under 350 W Xe lamp irradiation (λ ≥ 420 nm) with a sacrificial agent. The results proved that Ni3C NPs were efficient cocatalysts for photocatalytic H2 evolution over CdS NSs. The CdS-1% Ni3C hybrid NSs exhibited the highest photocatalytic H2-evolution rates of 357 μmol h−1 in 0.25 M Na2S-Na2SO3 and 450.5 umol h−1 in lactic acid, which were approximately 7.76 and 4.79 times higher than that of bare CdS NSs, corresponding to the apparent quantum yields of 7.58% and 8.72% at 420 nm, respectively. Clearly, the Ni3C NPs serve as H2-evolution electrocatalysts either in acidic or basic media. It is believed that the noble-metal-free Ni3C cocatalyst NPs on the surface of CdS NSs can effectively increase the visible-light absorbance, promote the charge carriers separation and transfer, improve the surface H2-evolution kinetics, thus achieving the obviously boosted hydrogen evolution. It is hoped that this study could contribute to the further investigation in exploiting the low-priced, high efficiency and environmentally friendly noble-metal-free cocatalysts for photocatalytic H2 evolution.