Enhanced visible light photocatalytic H2 production over Z-scheme g-C3N4 nansheets/WO3 nanorods nanocomposites loaded with Ni(OH)x cocatalysts

Novel WO(3)g-C3N4Ni(OH)(x) hybrids have been successfully synthesized by a two-step strategy of high temperature calcination and in situ photodeposition. Their photocatalytic performance was investigated using TEOA as a hole scavenger under visible light irradiation. The loading of WO3 and Ni(OH)(x) cocatalysts boosted the photocatalytic H-2 evolution efficiency of g-C3N4. WO3/g-C3N4Ni(OH)(x) with 20 wt%defective WO3 and 4.8 wt%Ni(OH)(x) showed the highest hydrogen production rate of 576 mu mol/(gh), which was 5.7, 10.8 and 230 times higher than those of g-C3N4/4.8 wt%Ni(OH)(x), 20 wt%WO3C3N4 and g-C3N4 photocatalysts, respectively. The remarkably enhanced H2 evolution performance was ascribed to the combination effects of the Z-scheme heterojunction (WO3/g-C3N4) and loaded cocatalysts (Ni(OH)(x)), which effectively inhibited the recombination of the photoexcited electron-hole pairs of g-C3N4 and improved both H-2 evolution and TEOA oxidation kinetics. The electron spin resonance spectra of O-2(-) and . OH radicals provided evidence for the Z-scheme charge separation mechanism. The loading of easily available Ni(OH)(x) cocatalysts on the Z-scheme WO3/g-C3N4 nanocomposites provided insights into constructing a robust multiple-heterojunction material for photocatalytic applications. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.