MnO_(x)is commonly used as an oxidative cocatalyst to promote charge carrier separation,yet,its underlying mechanism remains incompletely understood.In this study,MnO_(x)nanoparticles were deposited onto the surface o...MnO_(x)is commonly used as an oxidative cocatalyst to promote charge carrier separation,yet,its underlying mechanism remains incompletely understood.In this study,MnO_(x)nanoparticles were deposited onto the surface of BiFeO_(3)nanosheets via a photodeposition method,and their promoting effects in piezocatalytic and piezo-photocatalytic reactions were systematically investigated.The synthesized MnO_(x)/BiFeO_(3)composites exhibited enhanced catalytic performance in RhB degradation.In the piezocatalytic system,the optimized MnO_(x)/BiFeO_(3)catalyst achieved a degradation rate constant of 0.78 h−1,approximately 4.6 times that of pure BiFeO_(3).Under simultaneous ultrasonic vibration and light irradiation,the rate constant further increased to 1.4 h−1,representing 1.8 times and 1.4 times the rates observed under individual piezocatalytic and photocatalytic conditions,respectively.Comprehensive characterization techniques were employed to elucidate the mechanism behind the enhanced performance.The results reveal that MnO_(x)modification induces interfacial stress,enhancing the piezoelectric response of BiFeO_(3).Moreover,an S-scheme heterojunction is formed at the MnO_(x)/BiFeO_(3)interface,wherein holes in the valence band of BiFeO_(3)recombine with electrons from MnO_(x),effectively promoting charge separation and transport while preserving the strong redox capability of both charge carriers.The synergistic piezo-photocatalytic effect of MnO_(x)/BiFeO_(3)is attributed to the global piezoelectric potential of BiFeO_(3),which extends the spatial range of interfacial charge separation within the S-scheme heterojunction.Additionally,the high-density photogenerated electron–hole pairs produced under light irradiation effectively supplement the intrinsic charge carriers.This study not only clarifies the potential mechanism by which MnO_(x)functions as a hole-trapping cocatalyst,but also highlights the unique advantages of S-scheme heterojunctions in the field of piezo-photocatalysis,offering valuable insights for the design of efficient piezocatalytic materials.展开更多
基金supported by the National Natural Science Foundation of China(no.22172144 and 22272151)Key Research and Development Program of Zhejiang Province(2023C03148).
文摘MnO_(x)is commonly used as an oxidative cocatalyst to promote charge carrier separation,yet,its underlying mechanism remains incompletely understood.In this study,MnO_(x)nanoparticles were deposited onto the surface of BiFeO_(3)nanosheets via a photodeposition method,and their promoting effects in piezocatalytic and piezo-photocatalytic reactions were systematically investigated.The synthesized MnO_(x)/BiFeO_(3)composites exhibited enhanced catalytic performance in RhB degradation.In the piezocatalytic system,the optimized MnO_(x)/BiFeO_(3)catalyst achieved a degradation rate constant of 0.78 h−1,approximately 4.6 times that of pure BiFeO_(3).Under simultaneous ultrasonic vibration and light irradiation,the rate constant further increased to 1.4 h−1,representing 1.8 times and 1.4 times the rates observed under individual piezocatalytic and photocatalytic conditions,respectively.Comprehensive characterization techniques were employed to elucidate the mechanism behind the enhanced performance.The results reveal that MnO_(x)modification induces interfacial stress,enhancing the piezoelectric response of BiFeO_(3).Moreover,an S-scheme heterojunction is formed at the MnO_(x)/BiFeO_(3)interface,wherein holes in the valence band of BiFeO_(3)recombine with electrons from MnO_(x),effectively promoting charge separation and transport while preserving the strong redox capability of both charge carriers.The synergistic piezo-photocatalytic effect of MnO_(x)/BiFeO_(3)is attributed to the global piezoelectric potential of BiFeO_(3),which extends the spatial range of interfacial charge separation within the S-scheme heterojunction.Additionally,the high-density photogenerated electron–hole pairs produced under light irradiation effectively supplement the intrinsic charge carriers.This study not only clarifies the potential mechanism by which MnO_(x)functions as a hole-trapping cocatalyst,but also highlights the unique advantages of S-scheme heterojunctions in the field of piezo-photocatalysis,offering valuable insights for the design of efficient piezocatalytic materials.
