Dual-functional amino-abundance ultrathin porous boron-doped g-C3N4 co-catalyst for lead halide perovskite-based efficient photocatalytic CO2 reduction

Abstract

Development of efficient co-catalysts is a crucial strategy to improve photocatalytic CO₂ reduction reaction of lead halide perovskites. In this work, dual-functional amino-abundance ultrathin porous boron-doped g-C₃N₄ (NH₂-PB-CN) cocatalyst with solid-state proton donor is developed utilizing melamine as precursor material, NH₄Cl as bubble template and H₃BO₃ as boron-dope source. On the one hand, NH₂-PB-CN as co-catalyst forms II-type heterojunction with CsPbBr₃, and photogenerated electrons would accumulate on the conduction band of NH₂-PB-CN, whose large specific surface area increases the active sites for adsorption and activation of CO₂ molecules. Moreover, compared with control g-C₃N₄ samples, the enhanced reduction potential of NH₂-PB-CN also contributes to CO₂ conversion. On the other hand, abundant amino groups on NH₂-PB-CN as solid-state proton donor provide more protons for CO₂ reduction than H₂O proton source. To explore the effect of different functional groups on proton supply and CO₂ conversion, OH-CN and SO₃H-CN as control co-catalysts are synthesized. As a result, product yield of MF/NH₂-PB-CN/CsPbBr₃ reaches 103.21 μmol/g/h, which is 2.5, 1.1 and 1.7 times higher than those of MF/CN/CsPbBr₃ with H₂O as proton source, MF/OH-CN/CsPbBr₃ and MF/SO₃H-CN/CsPbBr₃ with solid-state proton donors, respectively, suggesting the effective proton supply from amino groups. MF/NH₂-PB-CN/CsPbBr₃ also exhibits strong stability and sufficient proton supply, with no obvious yield decrease after four 8-h cyclic measurements.