Controllable Synthesis of Pd/CuxCo3-xOn Interfaces for Highly Efficient Catalytic Combustion of Toluene
冯一纳 南京大学化学化工学院介观化学教育部重点实验室, 南京 210023  
曾亦强 南京大学化学化工学院介观化学教育部重点实验室, 南京 210023  
蒋武 南京大学化学化工学院介观化学教育部重点实验室, 南京 210023  
季伟捷 南京大学化学化工学院介观化学教育部重点实验室, 南京 210023 jiwj@nju.edu.cn 
摘要: 采用水热合成法制备了形貌规整且主要暴露晶面为(112)面的Co3O4六角片,在此基础上掺杂了适量的Cu元素,并且可控沉积了窄尺寸分布的Pd粒子。制备过程简单、绿色且产率高。所得材料应用于催化甲苯完全氧化反应时表现出优异的催化性能,其中Pd/h-Cu0.18Co2.82OnT90(甲苯的转化率达到90%时的反应温度)低至198℃。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积测试(BET)、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)对催化剂的结构和理化性质进行了表征。结果表明,适宜量的Cu掺杂后Co3O4基底氧空位增多,活化氧的能力增强,表面存在丰富的吸附氧物种,表现出与贵金属基催化剂相媲美的催化活性。引入的Pd组分主要以PdO形式存在,基底Cu掺杂进一步提升了Pd的氧化态,表面高反应性的氧种更多,反应活性更高。
关键词: 催化燃烧反应  规整形貌  Co3O4      甲苯
基金项目: 国家自然科学基金委(No.21173118,21373110)资助项目
Abstract: The morphologically uniform Co3O4 hexagonal plates (h-Co3O4) with the dominantly exposed (112) facet were fabricated by a hydrothermal synthesis approach. Then Cu elemental doping was successfully applied to the h-Co3O4 substrate, and further controllable deposition of Pd nanoparticles with a narrow size distribution was achievevd. All the fabrication procedures were technically simplified and environmentally friendly, with high production efficiency. Among the various catalysts, the Pd/h-Cu0.18Co2.82On showed the lowest T90 value (the reaction temperature at which the conversion rate of toluene reaches 90%) (198℃) for toluene combustion. The structural and physicochemical properties of catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption-desorption (BET), hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the specific surface area of the substrate decreased after the Cu doping into Co3O4, accompanying with the enriched surface defects (oxygen vacant sites) responsible for the enhanced capability of oxygen adsorption/activation and the abundant oxygen adspecies as a result. These characters ensured a promising catalyst performance comparable to that of noble metal-based catalysts. The surface dispersed Pd component was found to mainly exist in the form of PdO, and the Cu-doping of substrate further increased the oxidation state of Pd species, accounting for the existence of highly reactive oxygen species in a greater amount.
Keywords: catalytic combustion reaction  regular morphology  Co3O4  copper  palladium  toluene
投稿时间:2019-03-12 修订日期:2019-04-24
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