Dong Fan, Li Qiuyan, Zhou Ying, Sun Yanjun, Zhang Haidong, Wu Zhongbiao
Chongqing Key Laboratory of Catalysis and Functional Organic Molecules, College of Environmental and Biological Engineering, Chongqing Technology and Business University, Chongqing, 400067, China.
Dalton Trans. 2014 Jul 7;43(25):9468-80. doi: 10.1039/c4dt00427b.
Novel plasmonic 0D Ag nanocrystal decorated 3D (BiO)2CO3 hierarchical microspheres were fabricated with a one-pot hydrothermal method. The as-prepared samples were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectra, ns-level time-resolved fluorescence spectra, photocurrent generation and EIS measurement. The results indicated that the 0D Ag nanoparticles were deposited on the surface of 3D (BiO)2CO3 hierarchical microspheres. The deposited Ag nanoparticles were reduced from Ag(+) by the citrate ions from bismuth citrate. The photocatalytic activity of the as-prepared samples was evaluated towards the degradation of NO at ppb-level under visible light irradiation. The intermediate NO2 was monitored on-line during the photocatalytic reaction. The pure (BiO)2CO3 microspheres exhibited decent visible light photocatalytic activity because of the surface scattering and reflecting (SSR effect) resulting from the special 3D hierarchical architecture. The Ag-decorated (BiO)2CO3 microspheres (Ag/BOC) exhibited greatly enhanced photocatalytic activity, photocurrent generation and promoted NO2 oxidation compared to the pure (BiO)2CO3 microspheres. The enhanced photocatalytic activity and photocurrent generation of Ag/BOC was ascribed to the cooperative contribution of the surface plasmon resonance (SPR effect), efficient separation of electron-hole pairs and prolonged lifetime of charge carriers induced by Ag nanoparticles. The photocatalytic performance of Ag/BOC was dependent on the content of Ag loading. When the amount of Ag is controlled at 5%, the highest photocatalytic performance can be achieved. Further increasing the Ag loading content promotes aggregation of the Ag particles and transforms the uniform microspheres into non-uniform microspheres, which is not beneficial to improving the activity. Importantly, the as-prepared Ag/BOC composites exhibited high photochemical stability after multiple reaction runs. The concepts of enhancing the activity through the SSR and SPR effects provide a new avenue for the development of efficient noble metal/bismuth-based plasmonic photocatalysts with attractive nano/micro architectures for efficient visible light photocatalytic activity.
采用一锅水热法制备了新型等离子体零维银纳米晶体修饰的三维（BiO）₂CO₃分级微球。通过X射线衍射、扫描电子显微镜、透射电子显微镜、N₂吸附-脱附等温线、X射线光电子能谱、紫外-可见漫反射光谱、光致发光光谱、纳秒级时间分辨荧光光谱、光电流产生和电化学阻抗谱测量对所制备的样品进行了系统表征。结果表明，零维银纳米颗粒沉积在三维（BiO）₂CO₃分级微球的表面。沉积的银纳米颗粒由柠檬酸铋中的柠檬酸根离子将Ag(+)还原得到。在可见光照射下，对所制备样品对ppb级NO降解的光催化活性进行了评价。在光催化反应过程中对中间产物NO₂进行了在线监测。纯（BiO）₂CO₃微球由于特殊的三维分级结构产生的表面散射和反射（SSR效应）而表现出良好的可见光光催化活性。与纯（BiO）₂CO₃微球相比，Ag修饰的（BiO）₂CO₃微球（Ag/BOC）表现出大大增强的光催化活性、光电流产生以及促进的NO₂氧化。Ag/BOC光催化活性和光电流产生的增强归因于表面等离子体共振（SPR效应）的协同作用、电子-空穴对的有效分离以及由银纳米颗粒诱导的电荷载流子寿命的延长。Ag/BOC的光催化性能取决于Ag负载量。当Ag的量控制在5%时，可以实现最高的光催化性能。进一步增加Ag负载量会促进Ag颗粒的聚集，并将均匀的微球转变为不均匀的微球，这不利于活性的提高。重要的是，所制备的Ag/BOC复合材料在多次反应运行后表现出高光化学稳定性。通过SSR和SPR效应提高活性的概念为开发具有吸引人的纳米/微结构以实现高效可见光光催化活性的高效贵金属/铋基等离子体光催化剂提供了一条新途径。
