Single-Atom Ru Alloyed with Ni Nanoparticles Boosts CO Methanation.

Designing catalysts to proceed with catalytic reactions along the desired reaction pathways, e.g., CO methanation, has received much attention but remains a huge challenge. This work reports one RuNi single-atom alloy (SAA) catalyst (RuNi/SiO) prepared via a galvanic replacement reaction between RuCl and Ni nanoparticles (NPs) derived from the reduction of Ni phyllosilicate (Ni-ph). RuNi/SiO achieved much improved selectivity toward hydrogenation of CO to CH and catalytic activity (Turnover frequency (TOF) value: 40.00 × 10 s), much higher than those of Ni/SiO (TOF value: 4.40 × 10 s) and most reported Ni-based catalysts (TOF value: 1.03 × 10-11.00 × 10 s). Experimental studies verify that Ru single atoms are anchored onto the Ni NPs surface via the Ru-Ni coordination accompanied by electron transfer from Ru to Ni. Both in situ experiments and theoretical calculations confirm that the interface sites of RuNi-SAA are the intrinsic active sites, which promote the direct dissociation of CO and lower the energy barrier for the hydrogenation of CO* intermediate, thereby directing and enhancing the CO hydrogenation to CH.