内建电场与偶极场协同增强SnNb_(2)O_(6)/富氮C_(3)N_(5)S型异质结光催化性能

Synergistic Effects of Internal Electric and Dipole Fields in SnNb_(2)O_(6)/Nitrogen-Enriched C_(3)N_(5)S-Scheme Heterojunction for Boosting Photocatalytic Performance

定向电荷转移是调控光生载流子分离动力学的一种极具吸引力的策略。本文通过在SnNb_(2)O_(6)纳米片上原位生长C_(3)N_(5)纳米棒,设计一种具有强内建电场(IEF)和偶极场(DF)的新型2D/1D SnNb_(2)O_(6)/富氮C_(3)N_(5)S型异质结。通过构筑S型异质结,在界面处产生IEF,促进电荷从SnNb_(2)O_(6)向C_(3)N_(5)的定向迁移。与此同时,C_(3)N_(5)中的DF提供一种驱动力,将光生电子定向转移至活性位点。通过IEF和DF的协同效应,SnNb_(2)O_(6)/C_(3)N_(5)异质结实现了快速的定向电子转移,从而显著提高了电荷分离效率。研究结果表明,SnNb_(2)O_(6)/C_(3)N_(5)异质结的最佳产氢速率高达1090.0μmol·g^(-1)·h^(-1)(反应过程中持续释放H2气泡),分别是SnNb_(2)O_(6)和C_(3)N_(5)的38.8和10.7倍。此外,SnNb_(2)O_(6)/C_(3)N_(5)异质结在去除罗丹明B、四环素和Cr(Ⅵ)方面也表现出优异的光催化性能。通过电子顺磁共振(EPR)、时间分辨光致发光光谱(TPRL)和密度泛函理论(DFT)计算,本文系统探讨了SnNb_(2)O_(6)/C_(3)N_(5)异质结的定向电荷转移机制。这项研究为开发高效异质结光催化剂提供了一种可行的方法。

Directional electron transfer is an appealing strategy for harnessing photogenerated charge separation kinetics.Herein,a novel 2D/1D SnNb_(2)O_(6)/nitrogen-enriched C_(3)N_(5) Sscheme heterojunction with strong internal electric field(IEF)and dipole field(DF)is designed through in situ growth of C_(3)N_(5) nanorods on SnNb_(2)O_(6) nanosheets.The IEF generated at the interface via the formation of the S-scheme heterojunction induces directional charge transfer from SnNb_(2)O_(6) to C_(3)N_(5).Simultaneously,the DF within C_(3)N_(5) provides the impetus to guide photo-excited electrons to the active sites.Consequently,the synergistic effects of IEF and DF facilitate swift directional electron transfer.The optimized SnNb_(2)O_(6)/C_(3)N_(5) heterojunction demonstrates a remarkable H2 production rate of 1090.0μmol·g^(-1)·h^(-1) with continuous release of H_(2) bubbles.This performance surpasses that of SnNb_(2)O_(6) and C_(3)N_(5) by 38.8 and 10.7 times,respectively.Additionally,the SnNb_(2)O_(6)/C_(3)N_(5) heterojunction exhibits superior activity in the removal of Rhodamine B,tetracycline,and Cr(Ⅵ).Based on electron paramagnetic resonance(EPR),time-resolved photoluminescence(TPRL)and density functional theory(DFT)calculations,etc.,the directional charge transfer mechanism was systematically explored.The research furnishes a plausible approach to construct effective heterojunction photocatalysts for applications in energy and environmental domains.