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Negi SS, Kim HM, Cheon BS, Jeong CH, Roh HS, Jeong DW. Restructuring Co-CoO x Interface with Titration Rate in Co/Nb-CeO 2 Catalysts for Higher Water-Gas Shift Performance. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37902875 DOI: 10.1021/acsami.3c09312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2023]
Abstract
H2 production via water-gas shift reaction (WGS) is an important process and applied widely. Cobalt-modified CeO2 are promising catalysts for WGS reaction. Herein, a series of Co/Nb-CeO2 catalysts were prepared by varying the rate of precipitant addition during the coprecipitation method and examined for hydrogen generation through WGS reaction. The rates of precipitant addition were 1, 5, 15, and 25 mL/min. We obtained ceria supported cobalt catalysts with different sizes and morphology such as 3, 8 nm nanoclusters, 30 nm cubic nanoparticles, and 50 nm hexagonal nanoparticles. The well dispersed small cobalt particles in Co/Nb-CeO2 that was prepared at 5 mL/min titration rate exhibit strong interaction between cobalt oxide and CeO2 that retards the reduction of CoOx producing Co-CoOx pairs. In contrast, 1-Co/Nb-CeO2 and 25-Co/Nb-CeO2 result in bigger and aggregated Co particles, resulting in fewer interfaces with CeO2. The Co0, Coδ+, Ce3+, and Ov species are responsible for improved reducibility in Co/Nb-CeO2 catalysts and were quantitively measured using XPS, XAS, and Raman spectroscopy. The Co-CoOx interface assists dissociation of the H2O molecule; CO oxidation requires low activation energy and realizes a high turnover frequency of 9.8 s-1. The 5-Co/Nb-CeO2 catalyst achieved thermodynamic equilibrium equivalent CO conversion with efficient H2 production during WGS reaction at a gas hourly space velocity of 315,282 h-1. Successively, the 5-Co/Nb-CeO2 catalyst exhibited stable performance for straight 168 h attributed to stable CO-Coδ+ intermediate formation, achieving efficient inhibition of typical CO chemistry over the Co metal, suitable for hydrogen generation from waste derived synthesis gas.
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Affiliation(s)
- Sanjay Singh Negi
- Industrial Technology Research Center, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
| | - Hak-Min Kim
- Industrial Technology Research Center, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
| | - Beom-Su Cheon
- Department of Environmental Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
| | - Chang-Hoon Jeong
- Department of Smart Environmental Energy Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
- Hydrogen Industry Planning Team, Changwon Industry Promotion Agency, 46 Changwon-daero, Changwon, Gyeongnam 51395, Republic of Korea
| | - Hyun-Seog Roh
- Department of Environmental and Energy Engineering, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon 26493, Republic of Korea
| | - Dae-Woon Jeong
- Department of Environment & Energy Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
- School of Smart & Green Engineering, Changwon National University, 20 Changwondaehak-ro, Changwon, Gyeongnam 51140, Republic of Korea
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Electrochemical Ce(III)/Ce(IV) interconversion, electrodeposition, and catalytic CO ↔ CO2 interconversion over terpyridine-modified indium tin oxide electrodes. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2021.11.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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