Gao, G.Jiao, Y.Ma, F.Jiao, Y.Waclawik, E.Du, A.2016-06-302016-06-302015Physical Chemistry Chemical Physics, 2015; 17(46):31140-311441463-90761463-9084http://hdl.handle.net/2440/100001Interfacing carbon nanodots (C-dots) with graphitic carbon nitride (g-C3N4) produces a metal-free system that has recently demonstrated significant enhancement of photo-catalytic performance for water splitting into hydrogen [Science, 2015, 347, 970-974]. However, the underlying photo-catalytic mechanism is not fully established. Herein, we have carried out density functional theory (DFT) calculations to study the interactions between g-C3N4 and trigonal/hexagonal shaped C-dots. We find that hybrid C-dots/g-C3N4 can form a type-II van der Waals heterojunction, leading to significant reduction of band gap. The C-dot decorated g-C3N4 enhances the separation of photogenerated electron and hole pairs and the composite's visible light response. Interestingly, the band alignment of C-dots and g-C3N4 calculated by the hybrid functional method indicates that C-dots act as a spectral sensitizer in hybrid C-dots/g-C3N4 for water splitting. Our results offer new theoretical insights into this metal-free photocatalyst for water splitting.enThis journal is © the Owner Societies 2015Journal article003003911910.1039/c5cp05512a0003654017000392-s2.0-84947782455220433