TY - JOUR
T1 - Catalytic ignition of CO over CuCeZr based catalysts: New insights into the support effects and reaction pathways
AU - Kang, Running
AU - Zhang, Zirui
AU - Bin, Feng
AU - Wei, Xiaolin
AU - Li, Yongdan
AU - Chen, Guoxing
AU - Tu, Xin
N1 - Funding Information:
We gratefully acknowledge the financial support from the National Natural Science Foundation of China (No. 52176141 ) and the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA21040500 ). R. Kang acknowledges the support from the China Scholarship Council (No. 202004910623 ).
Publisher Copyright:
© 2023 Elsevier B.V.
PY - 2023/6/15
Y1 - 2023/6/15
N2 - Self-sustained catalytic combustion is a promising strategy to remove CO from the off-gas produced during steelmaking, where the potential catalysts are bulk copper-cerium-zirconium mixed oxides or those supported on TiO2 or ZSM-5 substrates. In this study, the effects of the catalyst support on the CO catalytic ignition performance and reaction pathways were investigated by FTIR coupled with a novel in-situ cell, together with the state-of-the-art characterization techniques. The Infrared (IR) transmission cell equipped with a magnetically driven system, could effectively prevent overlaps between active intermediate peaks (Cu+-CO and Cu+(CO)2) and gaseous CO peaks. The Cu+ cations located at the phase interface are the main active sites. The Cu and Ce interactions lead to the formation of solid solutions of CuCe0.75Zr0.25Oδ (CuCeZr). The monocarbonyls [Cu+-CO] are the dominant species during CO oxidation, and the vacancies in the solid solutions are occupied by oxygen, accelerating the oxygen cycle. The TiO2 or ZSM-5 supports promote copper dispersion over CuCe0.75Zr0.25Oδ/TiO2 (CuCeZr/T) and CuCe0.75Zr0.25Oδ/ZSM-5 (CuCeZr/Z) catalysts, which can be attributed to their high surface areas (168.2 and 346.3 m2/g, respectively), while the Cu-Ce interactions are less relevant. Hence, CO oxidation mainly occurs at the phase interface between copper oxide and TiO2/ZSM-5. Dicarbonyls [Cu+(CO)2] are the main intermediates for the CuCeZr/T and CuCeZr/Z catalysts, and the Cu2+ species are reduced to form dicarbonyls that also take part in the oxidation process. Although a well copper dispersion enhances the activity of individual copper sites on the CuCeZr/T and CuCeZr/Z catalysts, considering the redshift of the carbonyl bands and the increase in CO adsorption, the close interactions and high contents of Cu and Ce favor the local accumulation of heat and mass transfer over bulk CuCeZr, leading to the ignition of CO at low temperatures.
AB - Self-sustained catalytic combustion is a promising strategy to remove CO from the off-gas produced during steelmaking, where the potential catalysts are bulk copper-cerium-zirconium mixed oxides or those supported on TiO2 or ZSM-5 substrates. In this study, the effects of the catalyst support on the CO catalytic ignition performance and reaction pathways were investigated by FTIR coupled with a novel in-situ cell, together with the state-of-the-art characterization techniques. The Infrared (IR) transmission cell equipped with a magnetically driven system, could effectively prevent overlaps between active intermediate peaks (Cu+-CO and Cu+(CO)2) and gaseous CO peaks. The Cu+ cations located at the phase interface are the main active sites. The Cu and Ce interactions lead to the formation of solid solutions of CuCe0.75Zr0.25Oδ (CuCeZr). The monocarbonyls [Cu+-CO] are the dominant species during CO oxidation, and the vacancies in the solid solutions are occupied by oxygen, accelerating the oxygen cycle. The TiO2 or ZSM-5 supports promote copper dispersion over CuCe0.75Zr0.25Oδ/TiO2 (CuCeZr/T) and CuCe0.75Zr0.25Oδ/ZSM-5 (CuCeZr/Z) catalysts, which can be attributed to their high surface areas (168.2 and 346.3 m2/g, respectively), while the Cu-Ce interactions are less relevant. Hence, CO oxidation mainly occurs at the phase interface between copper oxide and TiO2/ZSM-5. Dicarbonyls [Cu+(CO)2] are the main intermediates for the CuCeZr/T and CuCeZr/Z catalysts, and the Cu2+ species are reduced to form dicarbonyls that also take part in the oxidation process. Although a well copper dispersion enhances the activity of individual copper sites on the CuCeZr/T and CuCeZr/Z catalysts, considering the redshift of the carbonyl bands and the increase in CO adsorption, the close interactions and high contents of Cu and Ce favor the local accumulation of heat and mass transfer over bulk CuCeZr, leading to the ignition of CO at low temperatures.
KW - Carbon monoxide
KW - Copper-cerium-zirconium mixed oxide
KW - Magnetically driven IR cell
KW - Self-sustained catalytic combustion
KW - Support effect
UR - http://www.scopus.com/inward/record.url?scp=85147564053&partnerID=8YFLogxK
U2 - 10.1016/j.apcatb.2023.122435
DO - 10.1016/j.apcatb.2023.122435
M3 - Article
AN - SCOPUS:85147564053
SN - 0926-3373
VL - 327
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
M1 - 122435
ER -