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

•g-C3N4 quantum dots (CN QDs) were first reported to modified rutile TiO2 (rTiO2).•CN QDs-rTiO2 hybrid was prepared by a simple mixed-calcination process.•CN QDs were formed in-situ during calcination of melamine.•CN QDs-rTiO2 shows enhanced photocatalytic activity in degradation of RhB and NO.•A Z-scheme degradation mechanism was proposed for CN QDs-rTiO2 hybrid.

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.

Graphical abstractAn efficient visible-light driven Z-scheme hybridized photocatalyst was fabricated by modification of rutile TiO2 with g-C3N4 quantum dots (CN QDs-rTiO2).Download high-res image (272KB)Download full-size image