Highly efficient and enhanced sulfur resistance supported bimetallic single-atom palladium–cobalt catalysts for benzene oxidation
Highly efficient and enhanced sulfur resistance supported bimetallic single-atom palladium–cobalt catalysts for benzene oxidation
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DOI：
10.1016/j.apcatb.2020.119844
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发表时间：
2021-05
影响因子：
22.1
通讯作者：
Zhiquan Hou;Lingyun Dai;Yuxi Liu;Jiguang Deng;L. Jing;Wenbo Pei;Ruyi Gao;Yuan Feng;H. Dai-H.-Da
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文献类型：
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作者：
Zhiquan Hou;Lingyun Dai;Yuxi Liu;Jiguang Deng;L. Jing;Wenbo Pei;Ruyi Gao;Yuan Feng;H. Dai-H.-Da
催化氧化是彻底消除工业和交通运输活动中排放的挥发性有机化合物（VOCs）的有效途径之一。同时，单原子催化剂由于其高的金属原子利用率，在众多反应中具有良好的应用前景。在这项工作中，我们采用了一种新的策略来制备活性Pd/Co单原子催化剂（即，Pd_1Co_1/Al_2 O_3）催化氧化苯。通过像差校正的高角度环形暗场扫描透射电子显微镜和X射线吸收精细结构验证了原子分散的钯和钴物种在Al 2 O3上的成功形成。通过原位程序升温技术和原位漫反射傅里叶变换红外光谱，我们观察到钯和钴氧化物活性位的双重作用，从而提高了苯的氧化性能。在250 °C和空速为40，000 mL/（g h）的条件下，Pd 1Co 1/Al 2 O 3催化剂上苯的转化率达到90%.有趣的是，该催化剂还具有增强的抗硫性能。Pd和Co的单原子分散是催化剂活性中心良好再生能力的主要原因。此外，推测Pd 1Co 1/Al 2 O3催化剂上苯的氧化反应可能通过苯→环己二烯→苯酚→醌→马来酸酯→乙酸酯→ CO2和H2O的反应途径进行。研究结果为合理设计双活性中心单原子催化剂和理解VOCs氧化机理提供了有益的思路。
Catalytic oxidation is one of the effective pathways for completely eliminating volatile organic compounds (VOCs) emitted from industrial and transportation activities. Meanwhile, single-atom catalysts have excellent application prospects in numerous reactions due to their high metal atomic utilization efficiency. In this work, we adopted a novel strategy to prepare an active Pd/Co single-atom catalyst (i.e., Pd1Co1/Al2O3) for benzene oxidation. The successful formation of the atomically dispersed palladium and cobalt species on Al2O3was verified by the aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure. By the in situ temperature-programmed techniques and in situ diffuse reflectance Fourier transform infrared spectroscopy, we observed a double effect of the palladium and cobalt oxide active sites, resulting in an enhanced performance for benzene oxidation. A benzene conversion of 90 % was achieved over the Pd1Co1/Al2O3catalyst at 250 °C and a space velocity of 40,000 mL/(g h). Interestingly, the catalyst also possessed enhanced sulfur resistance performance. The good regeneration ability of the active sites in the catalyst was due to the single-atom dispersion of Pd and Co. In addition, we deduce that benzene oxidation might occur over Pd1Co1/Al2O3via a pathway of benzene → cyclohexadiene → phenol → quinone → maleate → acetate → CO2and H2O. We believe that the obtained results can provide a useful idea for rationally designing the double active site single-atom catalysts and understanding the mechanism of VOCs oxidation.