SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 50 ›› Issue (10): 215-221.DOI: 10.1016/j.cjche.2022.06.018

• Catalysis, Kinetics and Reaction Engineering • 上一篇    下一篇

Co3O4 with ordered pore structure derived from wood vessels for efficient Hg0 oxidation

Xiaopeng Zhang, Cheng Gao, Ziwei Wang, Ximiao Wang, Jie Cheng, Xinxin Song, Xiangkai Han, Ning Zhang, Junjiang Bao, Gaohong He   

  1. State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116023, China;School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
  • 收稿日期:2022-03-17 修回日期:2022-06-02 出版日期:2022-10-28 发布日期:2023-01-04
  • 通讯作者: Gaohong He,E-mail:hgaohong@dlut.edu.cn
  • 基金资助:
    We gratefully acknowledge the financial supports from the National Natural Science Foundation of China (51978124), Science Fund for Creative Research Groups of the National Natural Science Foundation of China (22021005), and the Cheung Kong Scholars Programme of China (T2012049).

Co3O4 with ordered pore structure derived from wood vessels for efficient Hg0 oxidation

Xiaopeng Zhang, Cheng Gao, Ziwei Wang, Ximiao Wang, Jie Cheng, Xinxin Song, Xiangkai Han, Ning Zhang, Junjiang Bao, Gaohong He   

  1. State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116023, China;School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
  • Received:2022-03-17 Revised:2022-06-02 Online:2022-10-28 Published:2023-01-04
  • Contact: Gaohong He,E-mail:hgaohong@dlut.edu.cn
  • Supported by:
    We gratefully acknowledge the financial supports from the National Natural Science Foundation of China (51978124), Science Fund for Creative Research Groups of the National Natural Science Foundation of China (22021005), and the Cheung Kong Scholars Programme of China (T2012049).

摘要: Catalytic oxidation of Hg0 to HgO is an efficient way to remove Hg0 from coal-fired flue gas. The catalyst with ordered pore structure can lower mass transfer resistance resulting in higher Hg0 oxidation efficiency. Therefore, in the present work, wood vessels were used as sacrificial template to obtain Co3O4 with ordered pore structure. SEM and BET results show that, when the mass concentrations of Co(NO3)2·6H2O was 20%, the obtained catalyst (Co3O4 [20%Co(NO3)2]) possesses better pore structure and higher surface area. It will expose more available surface active sites and lower the mass transfer resistance. Furthermore, XPS results prove that Co3O4 [20%Co(NO3)2] has the highest ratio of chemisorbed oxygen which plays an important role in Hg0 oxidation process. These results lead to a better Hg0 oxidation efficiency of Co3O4 [20%Co(NO3)2], which is about 90% in the temperature range of 200 to 350 ℃. Furthermore, Co3O4 [20%Co(NO3)2] has a stable catalytic activity, and its Hg0 oxidation efficiency maintains above 90% at 250 ℃ even after 90 h test. A probable reaction mechanism is deduced by the XPS results of the fresh, used and regenerated catalyst of Co3O4 [20%Co(NO3)2]. Chemisorbed oxygen can react with Hg0 forming HgO with the reduction of Co3+ to Co2+. And lattice oxygen and gaseous oxygen can supplement the consumption of chemisorbed oxygen to oxidize Co2+ to Co3+.

关键词: Wood vessel, Elemental mercury, Ce3O4, Ordered pore structure

Abstract: Catalytic oxidation of Hg0 to HgO is an efficient way to remove Hg0 from coal-fired flue gas. The catalyst with ordered pore structure can lower mass transfer resistance resulting in higher Hg0 oxidation efficiency. Therefore, in the present work, wood vessels were used as sacrificial template to obtain Co3O4 with ordered pore structure. SEM and BET results show that, when the mass concentrations of Co(NO3)2·6H2O was 20%, the obtained catalyst (Co3O4 [20%Co(NO3)2]) possesses better pore structure and higher surface area. It will expose more available surface active sites and lower the mass transfer resistance. Furthermore, XPS results prove that Co3O4 [20%Co(NO3)2] has the highest ratio of chemisorbed oxygen which plays an important role in Hg0 oxidation process. These results lead to a better Hg0 oxidation efficiency of Co3O4 [20%Co(NO3)2], which is about 90% in the temperature range of 200 to 350 ℃. Furthermore, Co3O4 [20%Co(NO3)2] has a stable catalytic activity, and its Hg0 oxidation efficiency maintains above 90% at 250 ℃ even after 90 h test. A probable reaction mechanism is deduced by the XPS results of the fresh, used and regenerated catalyst of Co3O4 [20%Co(NO3)2]. Chemisorbed oxygen can react with Hg0 forming HgO with the reduction of Co3+ to Co2+. And lattice oxygen and gaseous oxygen can supplement the consumption of chemisorbed oxygen to oxidize Co2+ to Co3+.

Key words: Wood vessel, Elemental mercury, Ce3O4, Ordered pore structure