Preparation of CuCoNiCeMn High-entropy Oxide and Its Catalytic Oxidation Performance for CO in Sintering Flue Gas

doi:10.15541/jim20260065

Abstract

Abstract: The iron ore sintering process is a major source of industrial CO emissions, characterized by large gas volumes, complex compositions, and wide fluctuations, making abatement challenging. To address this, the synergistic effects of multi-components in high-entropy oxides (HEOs) were exploited. A systematic study on preparation process optimization was conducted to explore the influence of high-entropy alloy oxides on CO catalytic oxidation, along with their water and sulfur resistance, and the underlying mechanism. Results show that catalysts prepared by the Sol-Gel method possess abundant multivalent metal ions and oxygen vacancies, achieving >95% CO conversion at 160 ℃ and a gas hourly space velocity (GHSV) of 48000 mL·g^-1·h^-1, with low-temperature activity (temperature corresponding to a CO conversion rate of 50% (T₅₀)=101 ℃) significantly better than co-precipitation and hydrothermal methods. The effects of preparation parameters (citric acid ratio, solution pH, and calcination temperature) on catalytic performance were detailed. Characterization results confirm that electron transfer among multivalent metal ions and the synergy with oxygen vacancies are key to enhanced activity. The catalyst retains 98% CO conversion under 10% (in volume) H₂O and operates stably for 24 h at 280 ℃ and 72000 mL·g^-1·h^-1, demonstrating excellent water resistance and thermal stability. It is speculated that its catalytic oxidation follows the Mars-van Krevelen (MvK) mechanism. This study reveals the reaction mechanism governed by multi-metal valence synergy, coexistence of lattice and adsorbed oxygen, and oxygen vacancies in HEOs, providing new theoretical and experimental foundations for designing low-cost, high-performance non-noble metal CO oxidation catalysts.

Key words: high-entropy oxide, CO catalytic oxidation, Sol-Gel method, low-temperature catalysis

CLC Number:

O643

LIU Jian, AN Weijia, GAO Qin, LI Jianhua, YANG Zongxiang, WANG Xiao, LIANG Yinghua, GE Jiaqi, CUI Wenquan. Preparation of CuCoNiCeMn High-entropy Oxide and Its Catalytic Oxidation Performance for CO in Sintering Flue Gas[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260065.

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