The two dimension carbon quantum dots modified porous g-C3N4/TiO2 nano-heterojunctions for visible light hydrogen production enhancement

`The dual function carbon quantum dots (C QDs) modified porous g-C3N4/TiO2 two dimension (2D) nano-heterojunctions are prepared by a simple route, through which the porous g-C3N4 nanosheets are prepared by thermal polycondensation, the TiO2 nano-particles are introduced by hydrothermal method and the C QDs are introduced on the surface of the porous g-C3N4 and TiO2 by coupling successively. The results indicate that TiO2 and C QDs are well combined with the porous g-C3N4. The hydrogen production properties of those 2D nano-heterojunctions are investigated, which exhibit an obvious hydrogen production enhancement (nearly two orders of magnitude) compared with those of the unmodified samples. Through analysis, this enhancement of the photocatalystic hydrogen production is attributed to the dual function C QDs with high catalytic activity of H2O2 decomposition and unique up-conversion photoluminescence. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.