Atomically dispersed cerium sites in carbon-doped boron nitride for photodriven CO2 reduction: Local polarization and mechanism insight

The rapid recombination of photogenerated electrons and holes on the bulk and surface of photocatalyst and the limited active sites seriously hinder the photocatalytic efficiency. Herein, we present a single-atom local coordination strategy to solve the above problems of C-BN photocatalysts. By introducing Ce atoms to form the Ce/B2N2 local structure, on the one hand, can effectively induce local polarization and form a local polarized electric field, which can promote the separation of photogenerated carriers. On the other hand, new Ce active sites are introduced and show a lower energy barrier for dissociation of the critical intermediate COOH*, while suppressing CH4 and H2 evolution in the competing reaction. The Ce/C-BN delivers a selective CO formation rate of 125.5 µmol g−1 h−1 in pure water and is one of the best photocatalysts in the system without additives. This work offers valuable guidance for the rational design of efficient photocatalysts.