SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 48 ›› Issue (8): 76-90.DOI: 10.1016/j.cjche.2021.08.027

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Low-temperature dry reforming of methane tuned by chemical speciations of active sites on the SiO2 and γ-Al2O3 supported Ni and Ni-Ce catalysts

Yimin Zhang1, Ruiming Zeng1, Yun Zu1, Linhua Zhu1, Yi Mei1, Yongming Luo3, Dedong He1,2   

  1. 1. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China;
    2. National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment, Tsinghua University, Beijing 100084, China;
    3. Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
  • 收稿日期:2021-05-15 修回日期:2021-08-29 出版日期:2022-08-28 发布日期:2022-09-30
  • 通讯作者: Yun Zu,E-mail:zuyun1990@126.com;Dedong He,E-mail:dedong.he@qq.com
  • 基金资助:
    This work is financially supported by the National Natural Science Foundation of China (22006059, 21968015), National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment (NEL-KF-201905), Applied Basic Research Program of Yunnan Province, China (202101AU070154, 2019FD034), Analysis and Testing Fund of Kunming University of Science and Technology (2020?T20200006).

Low-temperature dry reforming of methane tuned by chemical speciations of active sites on the SiO2 and γ-Al2O3 supported Ni and Ni-Ce catalysts

Yimin Zhang1, Ruiming Zeng1, Yun Zu1, Linhua Zhu1, Yi Mei1, Yongming Luo3, Dedong He1,2   

  1. 1. Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, China;
    2. National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment, Tsinghua University, Beijing 100084, China;
    3. Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
  • Received:2021-05-15 Revised:2021-08-29 Online:2022-08-28 Published:2022-09-30
  • Contact: Yun Zu,E-mail:zuyun1990@126.com;Dedong He,E-mail:dedong.he@qq.com
  • Supported by:
    This work is financially supported by the National Natural Science Foundation of China (22006059, 21968015), National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment (NEL-KF-201905), Applied Basic Research Program of Yunnan Province, China (202101AU070154, 2019FD034), Analysis and Testing Fund of Kunming University of Science and Technology (2020?T20200006).

摘要: The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO2 dry reforming of methane (LTDRM). In this work, typical catalysts of SiO2 and γ-Al2O3 supported Ni and Ni-Ce were designed and prepared. Importantly, the difference in the chemical speciations of active sites on the Ni-based catalysts is revealed by advanced characterizations and further estimates respective catalytic performance for LTDRM. Results show that larger[Nin0] particles mixed with [Ni-O-Sin]) species on the Ni/SiO2(R) make CH4 excessive decomposition, leading to poor activity and stability. Once the Ce species is doped, however, superior activity (59.0% CH4 and 59.8% CO2 conversions), stability and high H2/CO ratio (0.96) at 600?℃ can be achieved on the Ni-Ce/SiO2(R), in comparison with other catalysts and even reported studies. The improved performance can be ascribed to the formation of integral ([Nin0]-[CeIII-□-CeIII]) species on the Ni-Ce/SiO2(R) catalyst, containing highly dispersed [Nin0] particles and rich oxygen vacancies, which can synergistically establish a new stable balance between gasification of carbon species and CO2 dissociation. With respect to Ni-Ce/γ-Al2O3(R), the Ni and Ce precursors are easily captured by extra-framework Aln-OH groups and further form stable isolated ([Nin0]-[Ni-O-Aln]) and [CeIII-O-Aln] species. In such a case, both of them preferentially accelerate CO2 adsorption and dissociation, causing more carbon deposition due to the disproportionation of superfluous CO product. This deep distinguishment of chemical speciations of active sites can guide us to further develop new efficient Ni-based catalysts for LTDRM in the future.

关键词: CO2 dry reforming of methane, Low-temperature, Ni-based catalysts, Chemical speciations, Reforming reaction mechanisms

Abstract: The cognition of active sites in the Ni-based catalysts plays a vital role and remains a huge challenge in improving catalytic performance of low temperature CO2 dry reforming of methane (LTDRM). In this work, typical catalysts of SiO2 and γ-Al2O3 supported Ni and Ni-Ce were designed and prepared. Importantly, the difference in the chemical speciations of active sites on the Ni-based catalysts is revealed by advanced characterizations and further estimates respective catalytic performance for LTDRM. Results show that larger[Nin0] particles mixed with [Ni-O-Sin]) species on the Ni/SiO2(R) make CH4 excessive decomposition, leading to poor activity and stability. Once the Ce species is doped, however, superior activity (59.0% CH4 and 59.8% CO2 conversions), stability and high H2/CO ratio (0.96) at 600?℃ can be achieved on the Ni-Ce/SiO2(R), in comparison with other catalysts and even reported studies. The improved performance can be ascribed to the formation of integral ([Nin0]-[CeIII-□-CeIII]) species on the Ni-Ce/SiO2(R) catalyst, containing highly dispersed [Nin0] particles and rich oxygen vacancies, which can synergistically establish a new stable balance between gasification of carbon species and CO2 dissociation. With respect to Ni-Ce/γ-Al2O3(R), the Ni and Ce precursors are easily captured by extra-framework Aln-OH groups and further form stable isolated ([Nin0]-[Ni-O-Aln]) and [CeIII-O-Aln] species. In such a case, both of them preferentially accelerate CO2 adsorption and dissociation, causing more carbon deposition due to the disproportionation of superfluous CO product. This deep distinguishment of chemical speciations of active sites can guide us to further develop new efficient Ni-based catalysts for LTDRM in the future.

Key words: CO2 dry reforming of methane, Low-temperature, Ni-based catalysts, Chemical speciations, Reforming reaction mechanisms