MgAl-LDH强化Bi单质等离子体光催化性能的机制  

Mechanism of MgAl-LDH-induced enhancement in the plasmonic photocatalytic performance over bismuth nanospheres

作　　者：吕晓书 曹嘉真 李欣蔚[1] 曹继武 张贤明[1] 董帆[1] Xiaoshu Lu;Jiazhen Cao;Xinwei Li;Jiwu Cao;Xianming Zhang;Fan Dong(Engineering Research Center for Waste Oil Recovery Technology and Equipment,Ministry of Education,Chongqing Key Laboratory of Catalysis and New Environmental Materials,College of Environment and Resources,Chongqing Technology and Business University,Chongqing 400067,China)

机构地区：[1]重庆工商大学废油资源化技术与装备教育部工程研究中心催化与环境新材料重庆市重点实验室环境与资源学院,重庆400067

出　　处：《科学通报》2018年第25期2620-2630,共11页Chinese Science Bulletin

基　　金：国家万人计划青年拔尖人才项目;国家自然科学基金(21777011;21501016;51478070);环境与能源催化重庆市高校创新团队建设计划(CXTDG201602014);重庆市基础科学与前沿技术研究重点项目(cstc2017jcyjBX0052);重庆市基础研究与前沿技术研究项目(cstc2015jcyjA20007);重庆工商大学科研启动项目(2016-56-01);重庆工商大学新产品与技术开发课题(1556028)资助

摘　　要：通过液相超声辅助组装的方式将铋纳米球(Bi-NPs)均匀负载于层状氢氧化镁铝(MgAl-LDH)纳米片上,成功合成Bi@MgAl-LDH复合光催化剂.该催化剂在光照射下,可通过Bi单质等离子体效应连续高效氧化空气中ppb(十亿体积气体中所含污染物体积)浓度量级的NO(去除效率可稳定在56%).采用X射线衍射仪(XRD)、电子扫描显微镜(SEM)和紫外可见漫反射光谱(UV-visDRS)等手段对催化剂物相、形貌、化学组成和光学性质进行了表征分析,结合电子顺磁共振(ESR)氧化自由基捕获实验并采用原位红外光谱技术对光催化氧化NO过程进行动态监测发现,虽然MgAl-LDH作为载体没有与Bi球形成异质结结构,但其表面富含丰富的氢氧根离子,能与Bi球上光激发产生的空穴快速结合,形成·OH自由基;而光生空穴的快速消耗又能降低其与光生电子的复合,增强光电分离,促进超氧自由基形成,通过这两方面的协同作用增强了Bi球对NO的光催化氧化效果.更重要的是,LDH具有独特的水分子记忆效应,在光催化过程中被消耗的氢氧根离子可通过吸附空气中水分而不断补充,促使催化活性的稳定高效.本文的研究结果为Bi单质基等离子体直接光催化降解气相污染物性能强化提供了新的策略,同时对光催化反应机制的研究提出了新的思路.The rapid development of industry, automobiles and manufacturing has emitted an ever-growth amount of the atmospheric gas pollutants to the atmosphere, such as nitric oxide（NOx）, sulfur oxide（SOx）, volatile organic compounds（VOC） and particle matters（PM）. NO is deemed as one critical air pollutant as it is the leading origins of several environmental issues, such as the acidic rain, haze, and photochemical smog. To eliminate its environmental risk, it is highly desired to develop one effective, cost-effective and environmental-friendly technology to detect, regulate and remove them. Till now, various technologies have been developed, including the selective physical/chemical adsorption, heterogeneous catalytic reduction/oxidation and photocatalysis, to show high efficiency in separation, conversion and detoxification of NO. Among them, photocatalysis is receiving an ever-increased attention by its high efficiency, low cost and green feature（this technology enables the direct utilization of solar light to trigger the generation of highly active oxidative free radicals for pollutant degradation and mineralization）. In the development of photocatalytic technology, the core part is the design and synthesis of highly effective and durable photocatalyst. Plasmonic metal with a unique localized surface plasmon resonance（LSPR） feature have now emerged as one appealing class of photocatalysts with wide applications in environmental remediation and energy conversion. In the plasmonic metal-directed photocatalysis, the surface electrons of plasmonic metal oscillate resonated with the incident photon, giving rise to the generation of hot carriers for catalytic redox reactions. However, most of the current LSPR-directed photocatalysis is limited to the noble metal（Au and Ag）. Very recently, the earth-abundant bismuth metal（Bi） was confirmed to show a unique LSPR feature in visible light region, and more importantly, can serve as a direct plasmonic photocatalyst in ppb-level NO removal from a ga

关 键 词：Bi单质 表面等离子体效应 MgAl-LDH 光催化 原位红外光谱 

分 类 号：O643.36[理学—物理化学]