摘要
贵金属纳米颗粒的表面等离子共振效应使之在可见光区表现出显著的特征吸收.在可见光的诱导下,银/卤化银(Ag/Ag X,X=Cl,Br,I)复合物在污染物净化中表现出了优良的光催化性能.本研究采用室温沉淀法制备了Ag/Ag X等离子体光催化剂,对催化剂的微结构和光学性质进行了表征分析.将制备的Ag/Ag X应用于光催化净化空气中NO,Ag/Ag Cl因具有更强的等离子体效应和更高的电荷分离效率而表现出较高的光催化性能.运用原位红外光谱动态监测了Ag/Ag Cl光催化净化NO的反应过程,从分子层面揭示了Ag/Ag Cl等离子体可见光催化氧化NO的反应机理.本研究为贵金属基等离子体光催化剂的作用机理及空气净化应用提供了新的认识.
Photocatalysis technology could utilize solar energy for pollutants degradation and water splitting, displaying great potential in environmetnal remidiation and clean enerfy development. Significant progresses have been made on promoting photocatalysis efficiency and extending light absorption range. Specific semiconductors and plasmonic metals can behave photocatalysts. Recently, the plasmonic photocatalysis with Ag/AgX （X=Cl, Br, I） has been received increasing research interests. The preparation and application of Ag/AgX plasmonic photocatalysts have extensively explored. However, the Ag/AgX plasmonic photocatalysts were mainly applied in water splitting and degradation of aquous pollutants. The application of Ag/AgX in air purification has been rarely reported. Also, the mechanism of photocatalytic NO purification with Ag/AgX has never been revealed. Noble metal nanoparticles showed obvious characteristic absorption in the visible light region due to surface plasmon resonance effect. Under the induction of visible light, silver/silver halide （Ag/AgX, X=C1, Br, I） compounds shows excellent photocatalytic performance in the purification of pollutants. This research adopted the method of precipitation at room temperature to prepare Ag/AgX plasmonic photocatalyst. The formation of Ag metal on the AgX surface can be ascribed to the natural light illumination. The microstructure and optical properties of the as-prepared catalysts were characterized with XRD, SEM, UV-Vis DRS and PL techniques. The prepared Ag/AgX was applied in photocatalytic purification of ppb-level NO in the air. NO is one of the typical indoor and outdoor air pollutants. The results indicataed that the Ag/AgCl showed higher visible light photocatalytic performance due to the strong surface plasmon resonance absorption and the high charge separation efficiency in camparison with Ag/AgBr and Ag/AgI. The process of photocatalytic NO purification with Ag/AgC1 was dynamically monitored with in situ FT-IR equipped with an in situ diffuse-reflectance cell. The time-dependent evolution of IR peaks have been identified. The plasmonic visible light photocatalytic NO oxidation reaction mechanism with Ag/AgC1 was revealed at molecular level. The reaciton mechanism can be described as Ag＋visible light→e-＋h＋, e-＋O2→·02, h＋＋AgCl→Cl0＋Ag＋, ·O2＋NO→NO-3, Cl0＋NO→ Cl ＋NO-3 and CI-＋Ag＋→AgCl. The present work could provide a new perspective in the undestanding of the mechanism of noble metal based function plasmonic photocatalyst and air purification application.
出处
《科学通报》
EI
CAS
CSCD
北大核心
2016年第32期3482-3489,共8页
Chinese Science Bulletin
基金
国家重点研发计划(2016YFC0204702)
国家自然科学基金(21501016,51478070)
环境与能源催化重庆市高校创新团队建设计划(CXTDG201602014)
重庆市青年拔尖人才项目
重庆市大学生创新创业训练计划(201611799160)
大学生科技创新基金(163003)资助
关键词
Ag/AgX
等离子共振
光催化
NO净化
可见光
原位红外
silver/silver halide, plasmon, photocatalysis, NO purification, visible light, in situ FT-IR
