▎ 摘　　要

As a commonly used photocatalyst for oxygen evolution, monoclinic BiVO4 is rarely exploited in CO2 reduction due to its low conduction band. In this work, BiVO4 quantum dots with size of similar to 4.5 nm were synthesized through a sodium oleate modified hydrothermal process. The quantum dots show enhanced photocatalytic activity in converting CO2 to CO or CH4 compared with that in bulk. The enhanced photocatalytic activity is attributed to their evaluated conduction band when the material size reduces to nanoscale. Moreover, the photocatalytic activity can be further improved by combing with reduced graphene oxide. The reduced graphene oxide serves as a superior electron collector and transporter. Our results show a significantly improved photocatalytic activity (3.5 times) in CO2 reduction. This work would provide a feasible strategy to improve the photocatalytic activity of catalysts by using quantum structures, especially some catalysts which have a lower conduction band.