Unveiling the mechanistic synergy in Mn-doped NiO catalysts with atomic-burry structure: Enhanced CO oxidation via Ni-OH and Mn bifunctionality

• Published in: Separation and purification technology Vol. 354; p. 129330
• Main Authors: Zhou, Xiaoying, Fang, Shiyu, Zhang, Tiantian, Wu, Zuliang, Li, Jing, Wang, Wei, Zhu, Jiali, Wu, Junliang, Ye, Daiqi, Han, Rui, Liu, Qingling, Yao, Shuiliang, Gao, Erhao, Wu, Dayu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 19.02.2025
• Subjects: CO oxidation; DFT calculations; Mechanism; Mn-doped NiO; Non-noble metal-based catalysts; Mn-doped NiO; Non-noble metal-based catalysts; CO oxidation; DFT calculations; Mechanism
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2024.129330

[Display omitted] •Mn-doped NiO was prepared from the decomposition of nitrate precursor aerosols.•Mn-doped NiO of best performance has Mn-O-Ni and atom-burr structures.•CO conversion is 82% at –20 °C and 100% between 10 and 800 °C.•TOF value of CO oxidation on Mn-doped NiO is better than noble metal catalysts.•Operando DRIFTS-MS and DFT explore that OH at Ni and O at Mn dominate CO oxidation. The development of non-noble metal catalysts for low-temperature CO oxidation is a pivotal subject in various disciplines. In this study, an optimized Mn-doped NiO catalyst (Mn-NiO-0.5), prepared via aerosol pyrolysis with an equal molar ratio of Ni to Mn, demonstrates remarkable performance. It achieves an 82 % CO conversion at -20 °C and a 100 % conversion between 10 °C and 800 °C. The catalyst’s turnover frequency (TOF) for CO oxidation significantly surpasses that of previously reported noble-metal-based catalysts, underscoring its superior efficiency. Dynamic analyses suggest that the enhanced catalytic activity is a result of the unique atom burr structure, which presents an extensive surface area replete with abundant active sites. This structural feature is instrumental in maximizing the catalyst’s interaction with CO molecules. Experimental findings, corroborated by density functional theory (DFT) calculations, elucidate the mechanism of CO oxidation on the Mn-NiO-0.5 catalyst. The process is facilitated by the synergistic action of bimetallic sites, where the Ni–OH site acts as the primary adsorption point for CO. Subsequently, the CO is oxidized to bicarbonate through the interaction with the oxygen (O or O2) at adjacent Mn sites. This pioneering study introduces a paradigm-shifting insight: the effectiveness of non-noble metal oxide catalysts can now compete with, and in some cases, outperform their noble metal counterparts. This breakthrough is set to transform the industry, presenting a compelling alternative to conventional noble metal catalysts and propelling the evolution of state-of-the-art environmental conservation technologies.