BiOX/BiYO4(X=Cl,Br,I;Y=V,Nb)异质结微结构调控光催化性能

Photocatalytic technology can fundamentally solve environmental pollution and energy shortages. The project intends to combine theoretical design and characterization with experimental preparation and characterization to study and develope new and highly efficient bismuth-based BiOX/BiYO4(X=Cl,Br,I;Y=V,Nb) heterojunction composite photocatalytic materials. Based on density functional theory, semiconductor band theory, chemical bond theory and molecular orbital theory, we are going to study the design and preparation on the microscopic level. In order to prepare highly efficient BiOX/BiYO4 (X=Cl,Br,I;Y=V,Nb) heterojunction composite photocatalytic materials. Discussion of semiconductor heterojunction interface composite and its synergistic effect mechanism we mainly focus on study the photogenerated carriers separation and transfer process, to explore the interface recombination and their synergistic effect mechanism between semiconductor heterojunction interfaces, and to clarify the intrinsic relationship between the heterojunction composite structure and photocatalytic performance. The present proposal will be helpful to reveal the intrinsic relationship between the interface structure and macroscopic properties of the composite system of bismuth-based BiOX/BiYO4 (X=Cl,Br,I;Y=V,Nb) heterojunction composite structures. Consequently, the way for design and controllable preparing bismuth-based semiconductor/semiconductor heterojunction composites with efficient visible light photocatalytic activity will be found.

光催化对于从根本上解决环境污染和能源短缺等问题具有重要意义。本项目拟采用理论设计与表征结合实验制备与表征的方案，研究开发新型高效的BiOX/BiYO4 (X=Cl,Br,I; Y=V,Nb)异质结复合可见光催化材料。以密度泛函理论、半导体能带理论、化学键成键理论和分子轨道理论等作为理论基础，从微观结构层次进行BiOX/BiYO4 (X=Cl,Br,I; Y=V,Nb)异质结复合光催化材料的设计，然后实验制备。通过研究光生载流子分离和电荷转移过程，探讨半导体异质结界面复合及其协同作用机理，阐明BiOX/BiYO4 (X=Cl,Br,I; Y=V,Nb)异质结复合结构体系与光催化性能之间的内在关系，以期制备高效BiOX/BiYO4 (X=Cl,Br,I; Y=V,Nb)异质结复合光催化材料。本项目的实施，为设计和可控制备具有高效可见光催化活性的铋基半导体/半导体异质结复合材料提供支持和借鉴。

本项目就研究可见光响应铋基异质结复合光催化材料完成以下工作：.（1）对BiOBr/BiVO4异质结薄膜研究表明，BiVO4与BiOBr复合形成异质结后，各自晶体结构未变，在模拟太阳光辐射3 h后，纯BiVO4和BiOBr/BiVO4异质结薄膜对MB的降解率分别为63.33%和85.14%。.(2)理论研究掺杂对BiNbO4的影响，研究表明在富Bi 生长条件下，间隙位W（Wint） 和 Mo 施主缺陷最易形成且会导致n型导电特性。对（M＝Mo，W）单掺及M/Ovac共掺体系研究表明，Wint/Ovac共掺体系有可能在光解水时具有更好的光催化活性。.(3)对M (M=Mo, W) 掺杂BiVO4薄膜研究表明，掺杂量为4 at.%时，W和Mo掺杂BiVO4薄膜光生电流密度分别为纯的BiVO4薄膜的1.95和2.52倍，且光照下表现出较为优异的光电化学防腐蚀效果，Mo掺杂BiVO4薄膜在暗态下也对铜起到较好的防腐蚀效果。.(4)对Ag/AgI/BiVO4体系研究表明，Ag/AgI/BiVO4较BiVO4和AgI/BiVO4有更好的可见光催化活性。推断其机理在于形成的Z型异质结结构提高了光生电子转移效率，银纳米粒子起着电荷传输桥作用。.(5)对g-C3N4/BiVO4复合光催化剂研究表明，光照80 min后10 wt.% BiVO4/g-C3N4降解效率g-C3N4的2.35倍，起主要作用的活性自由基为h+和·O2-。重要原因之一是BiVO4的(121)晶面和g-C3N4的(100)面交叉以氧为桥梁形成异质结，能有效促进光生载流子的分离。.(6)对n-n同型异质结Se NRs/BiVO4研究表明：光照120 min后对RhB降解速率分别是纯Se NRs和BiVO4的6.1倍和3.4倍。·OH是活性自由基。相比于单体Se NRs和BiVO4，·OH含量大幅度增加。通过分析UV-Vis-DRS及Tauc图证实成功合成Z型异质结结构。.(7)探索具有吸附-光催化协同效应的BiOBr-PVP体系吸附机理，提出静电相互吸引的假设模型。在PVP的作用下，构成更多的高活性（001）面暴露的BiOBr-PVP球状结构，其中C=O双键上的电子传递到BiOBr表面，在BiOBr 和PVP之间形成了较强的施主-受主相互作用，使复合材料具有更负的Zeta电位，有利于带负电的有机污染物的吸附。