Strain-Induced Surface Interface Dual Polarization Constructs PML-Cu/Bi12O17Br2 High-Density Active Sites for CO2 Photoreduction

Abstract The insufficient active sites and slow interfacial charge transfer of photocatalysts restrict the efficiency of CO 2 photoreduction. The synchronized modulation of the above key issues is demanding and challenging. Herein, strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer (PML-Cu) and Bi 12 O 17 Br 2 (BOB), which triggers the surface interface dual polarization of PML-Cu/BOB (PBOB). In this multi-step polarization, the built-in electric field formed between the interfaces induces the electron transfer from conduction band (CB) of BOB to CB of PML-Cu and suppresses its reverse migration. Moreover, the surface polarization of PML-Cu further promotes the electron converge in Cu atoms. The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB, significantly promoting the adsorption and activation of CO 2 and CO desorption. The conversion rate of CO 2 photoreduction to CO for PBOB can reach 584.3 μmol g −1 , which is 7.83 times higher than BOB and 20.01 times than PML-Cu. This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.