Role of electronic modulation of Ni-Pr bimetallic catalyst for low-temperature CO2 methanation

초록

CO2 methanation has gained increasing attention as a viable strategy for carbon recycling and renewable energy storage. While Ni-based catalysts are widely used due to their cost-effectiveness and intrinsic activity, they often suffer from limited low-temperature performance. This work reports a superior catalytic activity of bimetallic Ni-Pr supported on silica (Ni-Pr/SiO2) catalysts (XCO2 = 82.6% and SCH4 = 99% at 350 degrees C), significantly outperforming the monometallic Ni/SiO2. We investigated how the Ni-Pr interaction modulates the electronic structure of Ni active sites to enhance CO2 activation and methanation efficiency. By systematically comparing various Ni:Pr compositions, we identified an optimal ratio (10:1) that maximizes this interaction. The Ni-Pr interface sites directly influenced the CO2 adsorption strength and activation, leading to increased conversion and CH4 selectivity at low temperatures. DFT analysis further revealed that the electronic structure of these bimetallic sites lowers the energy barrier for C--O bond cleavage, providing a more favorable reaction pathway. This study presents key mechanistic insights into the role of bimetallic electronic interactions in CO2 methanation and presents a rational design strategy for optimizing Ni-based catalyst systems.

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