Two dimensional N-doped ZnO-graphitic carbon nitride nanosheets heterojunctions with enhanced photocatalytic hydrogen evolution

The effective separation of photogenerated charge carriers, their transport and interfacial contact is of great significance for excellent performance of semiconductor based photo catalysts. Herein, we report the fabrication of two dimensional (2D) nanosheets heterojunction comprising of N-doped ZnO nanosheets loaded over graphitic carbon nitride (g-C3N4) nanosheets for enhanced photocatalytic hydrogen evolution. The prepared 2D-2D heterojunctions with varying amount of g-C3N4 nanosheets have been characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) techniques. The optimized heterojunction photocatalyst with 30 wt% of g-C3N4 nanosheets (NZCN30) exhibit hydrogen evolution rate of 18836 mu mol h(-1) g(cat)(-1) in presence of Na2S and Na2SO3 as sacrificial agents under simulated solar light irradiation. The enhanced photocatalytic performance of NZCN30 heterojunction has been supported well by photoluminescence and photo electrochemical investigations, which shows the minimum recombination rate and high photoinduced current density, respectively. In addition, the existence of 2D-2D interfacial contact plays a major role in enhanced H-2 evolution by high face-to-face contact surface area for separation of photogenerated charge carriers in space which facilitate their transfer for H-2 generation. This work paves way for the development of 2D-2D heterojunctions for diverse applications. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.