Use of synergistic effects of the co-catalyst, p-n heterojunction, and porous structure for improvement of visible-light photocatalytic H2 evolution in porous Ni2O3/Mn0.2Cd0.8S/Cu3P@Cu2S

The efficient separation and transfer of photogenerated charge carriers play indispensable roles in improving the photocatalytic H2 evolution activity. Herein, we designed a Ni2O3-modified Mn0.2Cd0.8S/Cu3P@Cu2S (MCS/CPS) p-n heterojunction structure with a porous morphology for efficient and stable photocatalytic H-2 evolution under visible-light irradiation. Novel porous Cu3P@Cu2S was obtained using a vulcanization method and Cu2S nanoparticles were grown uniformly in situ on the surface of Cu3P. Ni2O3 was adopted as a co-catalyst on the MCS/CPS p-n heterojunction surfaces to promote electrons transfer. Due to the synergistic effects of the co-catalyst, p-n heterojunction, and porous morphology, the as-synthesized Ni2O3/MCS/CPS composite with 9 wt% Ni2O3 and 2.5 wt% CPS exhibits an optimal photocatalytic H-2 evolution rate of 9.2 mmol g(-1) h(-1), which is 14.4 and 2.4 times higher than those of pure MCS and 9%Ni2O3/MCS, respectively. Meanwhile, the optimal sample exhibits an apparent quantum efficiency of 33.5% at 420 nm and an excellent stability under 20 h of irradiation. Moreover, a possible mechanism for the improved photoactivity of the as-synthesized Ni2O3/MCS/CPS composite has been discussed in this paper. (C) 2020 Elsevier B.V. All rights reserved.