Defect-Mediated Gold Substitution Doping in ZnO Mesocrystals and Catalysis in CO Oxidation
Defect-Mediated Gold Substitution Doping in ZnO Mesocrystals and Catalysis in CO Oxidation
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ZnO 介晶中缺陷介导的金取代掺杂及其 CO 氧化催化
DOI：
10.1021/acscatal.5b02093
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发表时间：
2016
期刊：
影响因子：
12.9
通讯作者：
Mou Chung-Yuan
中科院分区：
文献类型：
--
作者：
Liu Ming-Han;Chen Yun-Wen;Liu Xiaoyan;Kuo Jer-Lai;Chu Ming-Wen;Mou Chung-Yuan
高度分散的负载金具有很强的金属-载体相互作用，是一种理想的多相催化材料。不同于目前的分散策略，沉积金从溶液到支持，我们在这里报告了一种新的方法，生产高度分散的金团簇在氧化锌介晶。金团簇在富缺陷双刷ZnO介晶（TB-ZnO）上的形成是通过一个“进-出”过程进行的：（i）先用AuCl 4-沉积-沉淀Au，形成Au/Zn混合氧化物;（ii）加热后，细小的Au团簇从氧化物的底部向表面生长。TB-ZnO表现得像海绵一样，允许金原子大量分散到ZnO的纤锌矿结构中，其中Zn被金取代。在温和的热处理后，嵌入的金从ZnO载体的下面出现，在ZnO表面形成高度分散的Au纳米颗粒，其为约2nm。密度泛函理论计算表明，TB-ZnO中Au的掺杂是能量上的优势，Au在TB-ZnO中的迁移是缺陷介导的，该材料（Au/TB-ZnO）对CO的氧化具有良好的催化活性。利用富含空位缺陷的介晶金属氧化物作为载体，为制备高分散、高活性的负载型金属催化剂提供了一条新的途径。
Highly dispersed supported gold with strong metal–support interaction is a desirable material for heterogeneous catalysis. Unlike current dispersion strategies of depositing gold from solution to support, we report herein a new method of producing highly dispersed gold clusters on ZnO mesocrystal. The gold clusters appeared on defect-rich twin-brush ZnO mesocrystals (TB-ZnO) via an in-and-out process: (i) a mixed Au/Zn oxide was formed first after deposition-precipitation of Au with AuCl4–, (ii) fine Au clusters grow from the underneath to the surface of the oxide after heating. The TB-ZnO behaved like a sponge allowing gold atoms to heavily disperse into the wurtzite structure of ZnO with Zn-substitution by gold. After mild thermal treatment, the embedded gold emerged from underneath of the ZnO support to form highly dispersed Au nanoparticles of ∼2 nm on the ZnO surface. DFT calculation shows energetically favored Au-doping in TB-ZnO and facile defect-mediated migration of Au in it. The material (Au/TB-ZnO) gave outstanding activities for the catalysis of CO oxidation. The use of mesocrystals of metal oxide as supports, with rich vacancy defects, provides a new route for preparing highly dispersed and active supported metal catalysts.