Photoelectrocatalytic CO 2 Reduction to Formate Using a BiVO 4 /ZIF‐8 Heterojunction

Abstract Converting CO 2 into high‐value chemical fuels through green photoelectrocatalytic reaction path is considered as a potential strategy to solve energy and environmental problems. In this work, BiVO 4 /ZIF‐8 heterojunctions are prepared by in‐situ synthesis of ZIF‐8 nanocrystals with unique pore structure on the surface of BiVO 4 . The experimental results show that the silkworm pupa‐like BiVO 4 is successfully combined with porous ZIF‐8, and the introduction of ZIF‐8 can provide more sites for CO 2 capture. The optimal composite ratio of 4 : 1‐BiVO 4 /ZIF‐8 exhibits excellent CO 2 reduction activity and the lowest electrochemical transport resistance. In the electrocatalytic system, the formate Faraday efficiency of 4 : 1‐BiVO 4 /ZIF‐8 at −1.0 V vs. RHE is 82.60 %. Furthermore, in the photoelectrocatalytic system, the Faraday efficiency increases to 91.24 % at −0.9 V vs. RHE, which is 10.8 times higher than the pristine BiVO 4 . The results show that photoelectric synergism can not only reduce energy consumption, but also improve the Faraday efficiency of formate. In addition, the current density did not decrease during 34 h electrolysis, showing long‐term stability. This work highlights the importance of the construction of heterojunction to improve the performance of photoelectrocatalytic CO 2 reduction.