Bi/BiOI/(BiO)2CO3异质结可见光催化净化NO的性能增强  

A Bi/BiOI/(BiO)2CO3 heterostructure for enhanced photocatalytic NO removal under visible light

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作  者:孙艳娟 廖佳珍 董帆 吴素娟 孙立东 Yanjuan Sun;Jiazhen Liao;Fan Dong;Sujuan Wu;Lidong Sun(State Key Laboratory of Mechanical Transmission, School of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;Chongqing Key Laboratory of Catalysis and New Environmental Materials, College of Environment and Resources, Chongqing Technology and BusinessUniversity, Chongqing 400067, China;Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, Sichuan, China)

机构地区:[1]重庆大学材料科学与工程学院,机械传动国家重点实验室,重庆400044 [2]重庆工商大学环境与资源学院,催化与环境新材料重庆市重点实验室,重庆400067 [3]电子科技大学基础与前沿研究院,四川成都611731

出  处:《催化学报》2019年第3期362-370,共9页Chinese Journal of Catalysis

基  金:国家自然科学基金(21501016, 21777011, 51871037, 51501024);重庆市高校创新团队(CXTDG201602014);重庆市自然科学基金重点项目(cstc2017jcyjBX0052);中组部“万人计划”青年人才计划.

摘  要:窄带隙BiOI光催化剂因电荷重组速率快而导致其可见光下的光催化效率较低.本文以NaBH4为还原剂,采用简单的常温原位组装法在BiOI上构建氧空位、金属Bi颗粒和Bi2O2CO3共作用,以克服BiOI的缺点.在合成的三元Bi/BiOI/(BiO)2CO3中,氧空位、双异质结(即Bi/BiOI和BiOI/(BiO)2CO3)以及Bi粒子的表面等离子体共振效应均促进了电子-空穴分离和电荷载流子浓度的增加,从而提高了可见光的整体光催化效率.将制备的催化剂用于可见光下去除连续流空气中的ppb级NO.结果表明,Bi/BiOI/(BiO)2CO3的NO去除率显著增强,大约为50.7%,并远高于BiOI(1.2%).密度泛函理论计算和实验结果表明,Bi/BiOI/(BiO)2CO3复合材料可明显促进光催化NO氧化的活性氧生成.本文可提供一个新的策略来改性窄带隙半导体和探索其他含铋异质结构的可见光驱动光催化剂.XRD结果发现,BOI-70中出现Bi和(BiO)2CO3的特征峰,但BOI却很微弱;XPS结果表明,高价态Bi3+被NaBH4部分还原而形成低价态金属Bi颗粒,且I3d峰位结合能进一步证实了BOI-70样品中存在BiOI,由此可见,成功制备了三元Bi/BiOI/(BiO)2CO3异质结催化剂,EPR结果表明氧空位的产生.SEM和TEM结果表明,BiOI和三元Bi/BiOI/(BiO)2CO3催化剂为纳米片组装的花状结构.HRTEM的结果进一步显示了金属铋、正方晶相BiOI和(BiO)2CO3对应的晶格间距.紫外-可见光催化去除NO的测试结果表明,BOI-70(50.7%)的光催化活性明显高于BOI(1.2%)和P25(11.5%),且在循环测试实验中表现出优异的稳定性. UV-vis DRS测试结果显示, BOI-70具有更强的光吸收;PL结果表明,其光生电子-空穴对的分离效率更高.ESR结果表明,参与反应的主要活性物种为·O2-和·OH自由基. DFT计算结果证实了OVs对电荷载流子的局部环境和快速传输: OV为电子捕获陷阱,使电子从OVs转移到O2分子形成活性氧物种;O2表面的吸附能从无缺陷BiOI时的–0.29 eV降到有缺陷的–0.76 eV, O-Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi2O2CO3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO)2CO3, the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and Bi- OI/(BiO)2CO3), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO)2CO3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO)2CO3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.

关 键 词:BiOI 氧空位 异质结 表面等离子体共振效应 NO氧化 

分 类 号:O643.36[理学—物理化学;理学—化学]

 

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