Unique insights into photocatalytic VOCs oxidation over WO₃/carbon dots nanohybrids assisted by water activation and electron transfer at interfaces

Internal electric field (IEF) at heterojunction interfaces can separate photoexcited charge carriers and promote photocatalytic performance. Here we have modified WO₃ nanoplates with carbon dots (CDs) and constructed an interfacial IEF directing from CDs to WO₃ with assistance of their remarkably different work functions. Such electric field drove photoexcited electrons to transport towards CDs and retained photoexcited holes to stay at WO₃, achieving electron/hole spatial separation. H₂O preferred chemisorption on the five-coordinated W atoms of WO₃ with an elongated H-O bond and bent H-O-H angle, which allowed the activation of H₂O and favorable production of ·OH radicals. The WO₃/CDs (WC1) showed a superior photocatalytic activity for visible-light photooxidation of HCHO and CH₃COCH₃ with CO₂ production rate of 411 and 188 μmol g^-1 h^-1, respectively, outperforming most of WO₃-based photocatalysts. The enhanced photocatalytic performance correlated with the IEF-induced charge separation, favorable ·OH production and VOCs chemisorption. Our work confirms the role of CDs cocatalyst in the photocatalytic oxidation of VOCs, which will inspire enthusiasm to develop more advanced heterojunction photocatalysts involving carbon nanomaterials.