化工进展 ›› 2022, Vol. 41 ›› Issue (8): 4213-4223.DOI: 10.16085/j.issn.1000-6613.2021-1977

• 工业催化 • 上一篇    下一篇

CeO2的形貌对CuO/CeO2催化剂CO2加氢制甲醇性能的影响

张嘉琪1,2(), 林丽娜1,2, 高文桂1,2,3(), 祝星2,3   

  1. 1.昆明理工大学冶金与能源工程学院,云南 昆明 650093
    2.昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室,云南 昆明 650093
    3.冶金节能减排教育部工程研究中心,云南 昆明 650093
  • 收稿日期:2021-09-06 修回日期:2021-11-18 出版日期:2022-08-25 发布日期:2022-08-22
  • 通讯作者: 高文桂
  • 作者简介:张嘉琪(1997—),女,硕士研究生,研究方向为能源催化。E-mail:382732828@qq.com
  • 基金资助:
    省部共建复杂有色金属资源清洁利用国家重点实验室自主课题(CNMRCUTS2009);国家重点研发计划(2018YFB0605402-02)

Effect of CeO2 morphology on the performance of CuO/CeO2 catalyst for CO2 hydrogenation to methanol

ZHANG Jiaqi1,2(), LIN Lina1,2, GAO Wengui1,2,3(), ZHU Xing2,3   

  1. 1.Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, China
    2.State Key Laboratory for Clean Utilization of Complex Nonferrous Metal Resources, Kunming University of Science and Technology, Kunming 650093, Yunnan, China
    3.Engineering Research Center of Ministry of Education for Energy Conservation and Emission Reduction in Metallurgy, Kunming 650093, Yunnan, China
  • Received:2021-09-06 Revised:2021-11-18 Online:2022-08-25 Published:2022-08-22
  • Contact: GAO Wengui

摘要:

采用水热法制备CeO2纳米颗粒(W-CeO2)、CeO2纳米片(S-CeO2)、CeO2纳米棒(B-CeO2)及CeO2纳米八面体(O-CeO2),用浸渍法负载相同质量分数的铜形成CuO/CeO2催化剂。通过扫描电镜(SEM)、高分辨透射电子显微镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、自动吸附分析仪(BET)、H2程序升温还原(H2-TPR)、N2O滴定等表征技术对催化剂进行表征,并在可控温控压的固定床石英管反应器中对催化剂的催化性能进行评价。研究了不同形貌CuO/CeO2催化剂对CO2加氢制备甲醇的影响;结果表明,CuO/CeO2催化剂的催化活性存在明显的形貌依赖性,催化剂的暴露晶面、比表面积、表面碱性位点、表面氧缺陷的差异均会对CO2转化率、甲醇选择性和产率产生影响。其中,不同形貌CeO2优先暴露晶面的活性顺序为S-CeO2({100}+{110})>W-CeO2{100}>B-CeO2{111}≈O-CeO2{111},暴露晶面活性越高,催化剂表面氧缺陷越多,CuO-CeO2间相互作用越强,则催化活性越好。当为CuO/S-CeO2时,催化剂表面中碱性位点最多,催化剂比表面积为88.8m2/g,铜分散度为19.2%,CO2转化率为6.56%,甲醇选择性和收率为96.3%和0.063g/(gcat·h),催化活性最好,由活性评价试验得转化率由高到低依次为S-CeO2>B-CeO2>W-CeO2>O-CeO2,可知CeO2形貌差异会决定CuO/CeO2催化剂的物化性能和催化活性,从而提升对不同形貌CuO/CeO2催化剂催化CO2加氢制甲醇的基础认识。

关键词: CeO2形貌, 催化剂, 二氧化碳, 加氢, 甲醇

Abstract:

CeO2 nanoparticles(W-CeO2), CeO2 nanosheets(S-CeO2), CeO2 nanorods(B-CeO2) and CeO2 nano-octahedra(O-CeO2) were firstly prepared by hydrothermal method, and then CuO/CeO2 catalysts with fixed copper mass fraction were obtained by impregnation method. The catalysts were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), automated adsorption analyzer (BET), H2 programmed temperature rise reduction (H2-TPR), N2O titration and other characterization techniques, and their catalytic performance was assessed in a fixed bed quartz tube reactor with controlled temperature and pressure. The effects of the CuO/CeO2 catalyst morphology on the methanol production by CO2 hydrogenation were investigated. The catalytic activity of the CuO/CeO2 catalysts showed a strong dependence on their morphology, and the factors of the exposed crystalline surface, specific surface area, surface basic sites and surface oxygen defects of the catalysts all affected the CO2 conversion, methanol selectivity and the yield. Among them, the order of the activity of the preferentially exposed crystalline surfaces of CeO2 with different morphologies is S-CeO2({100}+{110})>W-CeO2{100}>B-CeO2{111}≈ O-CeO2{111}). The higher the activity of the exposed crystalline surfaces, the more oxygen defects on the catalyst surface, and the stronger the CuO/CeO2 interactions, the better the catalytic activity. Regarding CuO/S-CeO2, it had the most basic sites on the surface with a specific surface area of 88.8m2/g and copper dispersion of 19.2%, giving the best catalytic activity of CO2 conversion 6.56%, methanol selectivity 96.3% and yield 0.063g/(gcat·h). The activity evaluation tests showed the conversion rates of the catalysts were in the order of S-CeO2>B-CeO2>W-CeO2>O-CeO2, which indicates that the CeO2 morphology could determine the physical and chemical properties and the catalytic activity of the CuO/CeO2 catalysts.

Key words: CeO2 morphology, catalyst, carbon dioxide, hydrogenation, methanol

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