MnO2 and carbon nanotube co-modified C3N4 composite catalyst for enhanced water splitting activity under visible light irradiation

MnO2 and carbon nanotube co-modified C3N4 (CNTs/MnO2-C3N4) ternary composite was synthesized. The prepared catalyst was investigated by X-ray diffraction, transmission electron microscopy, UVVis absorption spectroscopy, nitrogen sorption, X-ray spectroscopy, photoluminescence spectroscopy and transient photocurrent responses. The photocatalytic activity of the ternary catalyst was evaluated by hydrogen and oxygen evolution for visible-light-driven water splitting without the addition of sacrificial agents. Compared with MnO2/C3N4 and CNTs/C3N4 catalysts, the CNTs/MnO2-C3N4 ternary catalyst showed an enhanced visible light-induced water splitting activity with a H-2 evolution rate of 122 mu mol h(-1). In the CNTs/MnO2-C3N4 ternary catalyst, CNT can capture the electron from C3N4 and facilitate hydrogen evolution, and MnO2 catalyzes the decomposition of hydrogen peroxide for O-2 evolution, leading to the efficient separation of photogenerated electron-hole pairs, thus an enhanced water splitting performance is achieved. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.