Construction of Frustrated Lewis Pair Sites in CeO2-C/BiVO4 for Photoelectrochemical Nitrate Reduction.

Photoelectrochemical nitrate reduction reaction (PEC NIRR) could convert the harmful pollutant nitrate (NO3-) to high-value-added ammonia (NH3) under mild conditions. However, the catalysts are currently hindered by the low catalytic activity and slow kinetics. Here, we reported a heterostructure composed of CeO2 and BiVO4, and the "frustrated Lewis pairs (FLPs)" concept was introduced for understanding the role of Lewis acids and Lewis bases on PEC NIRR. The electron density difference maps indicated that FLPs were significantly active for the adsorption and activation of NO3-. Furthermore, carbon (C) improved the carrier transport ability and kinetics, contributing to the NH3 yield of 21.81 µg h-1 cm-2. The conversion process of NO3- to NH3 was tracked by 15NO3- and 14NO3- isotopic labeling. Therefore, this study demonstrated the potential of CeO2-C/BiVO4 for efficient PEC NIRR and provided a unique mechanism for the adsorption and activation of NO3- over FLPs.