p-n Heterojunction Photocatalyst Mn0.5Cd0.5S/CuCo2S4 for Highly Efficient Visible Light-Driven H2 Production

Mingyue Zhang; Ningjie Fang; Xincheng Song; Yinghao Chu; Song Shu; Yongjun Liu

doi:10.1021/acsomega.0c05106

p-n Heterojunction Photocatalyst Mn_0.5Cd_0.5S/CuCo₂S₄ for Highly Efficient Visible Light-Driven H₂ Production

ACS Omega. 2020 Dec 8;5(50):32715-32723. doi: 10.1021/acsomega.0c05106. eCollection 2020 Dec 22.

Authors

Mingyue Zhang¹, Ningjie Fang¹, Xincheng Song¹, Yinghao Chu^{1

2}, Song Shu¹, Yongjun Liu^{1

2}

Affiliations

¹ College of Architecture and Environment, Sichuan University, Chengdu 610065, Sichuan, China.
² National Engineering Technology Research Center for Flue Gas Desulfurization, Chengdu 610065, Sichuan, China.

Abstract

It is highly important to develop efficient and cheap photocatalysts for hydrogen production. Herein, a series of p-n heterojunction Mn_0.5Cd_0.5S/CuCo₂S₄ has been successfully synthesized for the first time by the hydrothermal impregnation method. Mn_0.5Cd_0.5S/CuCo₂S₄ loading with 12 wt % CuCo₂S₄ shows the highest H₂ evolution rate of 15.74 mmol h^-1 g^-1 under visible light (λ ≥ 420 nm) irradiation, which is about 3.15 and 15.28 times higher than that of bare Mn_0.5Cd_0.5S (4.99 mmol h^-1 g^-1) and CuCo₂S₄ (1.03 mmol h^-1 g^-1), respectively. In addition, it shows a relatively good stability during the five recycle tests, with about 20% loss of reaction rate compared to that of the first cycle. The superior photocatalytic performance is attributed to the effective separation and transfer of photogenerated charge carriers because of the formation of the p-n junction. The samples are systematically characterized by X-ray diffraction, ultraviolet-visible (UV-vis), diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, photoluminescence, EIS, and so on. UV-vis and EIS show that CuCo₂S₄ can effectively improve the visible light response of Mn_0.5Cd_0.5S/CuCo₂S₄ and promote the electron transfer from CuCo₂S₄ to the conduction band of Mn_0.5Cd_0.5S, so as to improve the photocatalytic efficiency. This study reveals that the p-n heterojunction Mn_0.5Cd_0.5S/CuCo₂S₄ is a promising photocatalyst to explore the photocatalysts without noble metals.