Low-temperature coke-free methane dry reforming on oxygen-vacancy-rich MgO/Ni@NiAlO

Nowadays, the world is facing huge environmental challenges due to increasing greenhouse gas emissions. Recently, DRM has received great attention as a highly efficient route for transforming two typical greenhouse gases, CH₄ and CO_2, into syngas (CO + H₂), a crucial intermediate for the production of high-value-added chemicals and fuels. Nickel-based DRM catalysts, renowned for their high activity and low cost, encounter challenges such as severe deactivation from sintering and carbon deposition.The catalytic performance of Ni-based catalysts was significantly enhanced through structural design and acid-base modification. For instance, basic promoters such as MgO improved CO₂ adsorption and activation, thereby suppressing coke formation on Ni-based catalysts, while a surrounded structure effectively inhibited Ni particle sintering. Therefore, the combination of a surrounded structure and an alkali additive may enable high stability and excellent resistance to coke.

Recently, a research team led by Prof. Xuefeng Guo (Nanjing University) and Prof. Weiping Ding (Nanjing University) &Dr.Qiuyue Wang (Nanjing University) designed a NiO@NiAlO catalyst with a surrounded structure, which was further modified with MgO viawet impregnation. The obtained 0.8MgO^WI/Ni@NiAlO catalyst exhibited remarkable activity for near-equilibrium conversion and maintained high stability for over 50 h without coking at 600 °C, which surpassed the state-of-the-art performance reported in this research field. The results were published in the ChineseJournal of Catalysis (DOI:10.1016/s1872-2067(25)64743-7).

TheNiO@NiAlO surrounded catalyst was synthesized by a simple ion-exchange method, and subsequently modified with MgO via wet impregnation (WI), incipient wetness impregnation (IWI), and grinding (G) to obtain 0.8MgO^WI/Ni@NiAlO, 0.8MgO^IWI/Ni@NiAlO, and 0.8MgO^G/Ni@NiAlO catalysts, respectively. The WI method enabled MgO incorporation into both the Ni core and the NiAlO shell, thereby generating abundant oxygen vacancies (O_v) and in-situ-formed Ni/MgNiO₂ interfaces. These features synergistically enhanced CO₂ activation, promoted the generation of active O* species, and effectively suppressed coking and sintering. In contrast, the 0.8MgO^IWI/Ni@NiAlO catalyst, with MgO mainly modifying the Ni core, formed Ni/MgNiO₂ interfaces that resisted sintering but suffered from reduced O_v concentration and a slightly acidic shell, leading to coking. Meanwhile, the 0.8MgO^G/Ni@NiAlO catalyst, with MgO confined to the NiAl₁₆O₁₀ shell, only increased O_v concentration via Al³⁺ substitution but failed to form Ni/MgNiO₂ interfaces, resulting in severe sintering.

In-situ characterizations confirmed that O_v played a crucial role in promoting CO₂ activation, producing active O* species that oxidized CHx* intermediates from CH₄ dissociation at Ni sites into CO and H₂, while simultaneously preventing coke formation. Therefore, the rational integration of a surrounded structure and MgO modification provided a distinct strategy to achieve highly active, coke-resistant, and sintering-resistant Ni-based catalysts for low temperature DRM.The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(25)64743-7).

About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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