二维三氧化钨的高密度纳米金颗粒负载及形成机制研究  

作　　者：祁蒙 惠飞 汪纯慧 周权 马培杰 庞大为 李炜 杨鲁岩 陈艳辉[1] 李昂 

机构地区：[1]北京工业大学固体微结构与性能研究所

出　　处：《科技创新导报》2019年第9期77-84,86,共9页Science and Technology Innovation Herald

基　　金：国家自然科学基金(项目编号:51872008)资助项目

摘　　要：金属氧化物基体上负载纳米贵金属材料相比氧化物衬底可大大提高其催化性能,提高传感效率并降低应用成本。简易高效的负载方法对于其商业推广等应用方面具有重要的促进作用。纳米氧化钨作为一种优良的气敏和光催化材料,在半导体气体传感、光催化、电极材料、光能器件等领域有着广泛的应用。通过贵金属负载的方法可以在氧化钨半导体表面形成丰富的活性中心,成为其性能提高的有效手段。然而负载方法过于复杂成本过高阻碍了负载催化剂大面积推广及商用化。本文通过一种简易,低成本的方法在欠氧型纳米片层状氧化钨颗粒上制备了高负载率Au/WO2.6复合材料。系列实验结果表明:反应时间在24h后负载率达到最高,负载率在5mL之前随金胶体的剂量增多而增多,但随后剂量的增多并不会增大负载量。化学反应后的热处理将有助于提高纳米金颗粒与氧化钨之间的粘附力,并在热处理温度200℃~400℃时负载体系最为稳定,基体不发生相变。热处理温度超过550℃以上后基体氧化钨粉末将从具有单斜结构转变为立方结构并使片层状结构转变成球形结构。通过对不同反应时间及Au剂量的产物的研究结果表明,金颗粒先在片层结构的台阶上生成,随着反应时间的增长或反应剂量的增多,金颗粒逐步合并长大并布满整个衬底的表面。系列倾转的高分辨图像研究了Au/WO2.6的界面微观结构,发现球状纳米Au颗粒以镶嵌方式与片层的氧化钨基体在界面处形成山丘状而与衬底结合在一起,这种牢固的界面为催化过程中物质与能量的转移提供了快速通道。这种简单易行的方法及其反应机制的研究为其大范围的推广及大规模生产提供了前期基础。Noble metal materials supported metal oxide have been widely used as catalysts and gas sensing materials due to its improved optical catalyst and gas censoring properties compared with base materials. A facial and effective supporting method or process can improve catalysis efficiency and decrease cost and make it applicable for commercialization. Tungsten oxide is a superior gas sensor and catalysis materials for widely applications in semiconducting sensor, photocatalyst, electrode and photodevices. Nobel metal supported on Tungsten oxide complex system can create more activity center in materialssur face and thus highly improve its efficiency. Conventional preparation method however is complicated and high cost which limitits widely application and commercialization. We prepared a full surface supported Aunanoparticles on an oxygen-deficient two-dimensional Tungsten oxide nanosheets. Series experiments indicates that the surface coverage of supporting Au nanoparticle happens after reaction for 24 h and further reaction wouldn’t improve its coverage ratio. Following heat treatment under 200℃~400℃didn’t keep the phase stable and strengthen the adherence between Au nanoparticles. Higher temperature than 550℃ change the base phase form monoclinic phase to cubic phase and changes its morphologies from sheet-like structure to ball-like shapes. Experiments of reaction time and dose of Au gels indicates that increase of time and Au dose increase the Au supporting rate. Au particles f irst stable in the steps of sheet-like structures and then cover all the material surface. Series tilting high resolution transmission electron microscope images on the Au/ WO2.6 boundary indicates that,ball-like Au decorated into the metal oxide base to form a mountain-like shape with a f lat boundary. between them. The type of adherence thus provides paths for materials and energy transfer in catalyst process. Our method is simple and low cost for widely application and commercialization.

关 键 词：负载催化剂 氧化钨 Au/WO2.6 表面界面 

分 类 号：O6[理学—化学]