In-situ electrochemical-ion-exchange synthesis of S-scheme 1D/2D BiPO4/BiOBr heterojunction film from Bi plate with highly efficient photocatalytic CO2 reduction activity

The construction of heterojunction structure is an effective strategy for solving photogenerated electron-hole recombination. In this work, a kind of 1D/2D S-scheme BiPO4/BiOBr heterojunction film is designed and constructed by in-situ electrochemical-ion-exchange method on Bi plate. The S-scheme transfer path of photogenerated electrons of BiPO4/BiOBr film is collaboratively confirmed through DFT calculation and in-situ X-ray photoelectron spectra. As-prepared S-scheme BiPO4/BiOBr heterojunction film has the higher CO2 photoreduction activity (296.5 μmol·g−1) to CO, 1.9 times than pure BiOBr film, which should be mainly attributed to improved light utilization efficiency and effective separation/migration of photogenerated electron-hole pairs.