Hybridization of rutile TiO2 (rTiO2) with g-C3N4 quantum dots (CN QDs): An efficient visible-light-driven Z-scheme hybridized photocatalyst

To make full use of solar light, fabrication of g-C3N4 quantum dots (CN QDs) modified rutile TiO2 (rTiO2) hybrid (CN QDs-rTiO2), using both visible light responsive semiconductors as components, was successfully achieved by calcination the mixture of P25 TiO2 and melamine at 500 °C for 4 h. It was found that CN QDs were in-situ formed during calcination, which were homogeneously deposited on the surface of rTiO2. Modification of rTiO2 by CN QDs not only improved the visible-light harvesting ability, but also retarded the recombination of photo-generated electron-hole pairs. CN QDs-rTiO2 hybrid (S15) with nominal 15 at.% CN QDs loading showed the highest photocatalytic activity among all the photocatalysts, whatever for degradation of RhB or photocatalytic decomposition of NO, under visible light irradiation. The increased formation of OH radicals in CN QDs modified rTiO2 suspensions supports a Z-Scheme degradation mechanism instead of the formation of CN QDs-rTiO2 heterojunctions.