OD/2D interface engineering of carbon quantum dots modified Bi2WO6 ultrathin nanosheets with enhanced photoactivity for full spectrum light utilization and mechanism insight

A novel full spectrum light driven carbon quantum dots (CQDs)/Bi2WO6 (CBW) hybrid materials were synthesized via a facile hydrothermal method. Multiple techniques including XRD, TEM, XPS, BET, UV-vis, XPS, PL and TRPL, were employed to investigate the structures, morphology, optical and electronic properties and photocatalytic performance of as-prepared samples. The results indicated that CBW heterojunctions were assembly of CQDs on m-BWO and presented high separation efficiency of photo-generated carriers and full light spectrum absorption. The photocatalytic mechanism of CBW hybrid materials was revealed, suggesting that the excellent photocatalytic activity towards organic pollutants was ascribed to the up converted photoluminescence (PL) and electron reservoir properties of CQDs. Density functional theory calculations indicated that complementary conduction and valence band-edge hybridization between CQDs and m-BWO could apparently increase separation efficiency of electron-hole pairs of CBW hybrid materials. According to ESR measurement and quenching experiments, the O-2 center dot(-), center dot OH and h(+) were the main active species during the photocatalytic process. This study could shed light on OD/2D interface engineering of carbon quantum dots based heterojunctions with enhanced photoactivity for full spectrum light utilization in pollutant degradation and energy conversion.