Single-Atom Ru Alloyed with Ni Nanoparticles Boosts CO₂ Methanation

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Catalytic conversion of carbon dioxide (CO2) into valuable products like methane is crucial for sustainable energy and environmental remediation.
• Designing catalysts with high selectivity and activity for specific reaction pathways, such as CO2 methanation, remains a significant challenge in heterogeneous catalysis.

Purpose of the Study:

• To develop and characterize a novel Ruthenium-Nickel single-atom alloy (Ru1Ni SAA) catalyst for enhanced CO2 methanation.
• To investigate the structure-activity relationship and understand the catalytic mechanism of the Ru1Ni SAA catalyst.

Main Methods:

• Synthesis of Ru1Ni SAA catalyst (Ru1Ni/SiO2) using a galvanic replacement reaction between RuCl3 and Ni nanoparticles (NPs).
• Characterization of the catalyst using various experimental techniques.
• Evaluation of catalytic performance for CO2 hydrogenation to CH4, including activity and selectivity measurements.
• In situ experiments and theoretical calculations to elucidate the reaction mechanism.

Main Results:

• The Ru1Ni/SiO2 catalyst exhibited significantly improved selectivity and catalytic activity for CO2 methanation compared to Ni/SiO2 and previously reported Ni-based catalysts.
• Turnover frequency (TOF) for Ru1Ni/SiO2 reached 40.00 × 10^-3 s^-1, substantially higher than Ni/SiO2 (4.40 × 10^-3 s^-1).
• Experimental and theoretical studies confirmed that the interface sites of Ru1Ni-SAA are the active centers, facilitating CO2 dissociation and lowering hydrogenation energy barriers.

Conclusions:

• The developed Ru1Ni SAA catalyst is highly effective for CO2 methanation, offering superior performance.
• The synergistic effect at the Ru-Ni interface is key to the enhanced catalytic activity and selectivity.
• This work provides a promising strategy for designing advanced single-atom alloy catalysts for CO2 conversion.