Bimetallic Ni-Co nanoparticles on SiO2 as robust catalyst for CO methanation: Effect of homogeneity of Ni-Co alloy

Abstract

Designing and tailoring the fine structure of bimetallic nanoparticles is an essential and effective way to boost the catalytic properties. Herein, two types of Ni-Co alloys are generated on SiO2 including non-homogeneous or homogeneous form for CO methanation. The formation of homogeneous Ni-Co alloy originates from the strong interaction between Ni and Co and a small amount of CoO. Compared with non-homogeneous alloy, the homogeneous Ni-Co alloy exhibits superior CO conversion and CH4 selectivity below 380 °C, and is stable for 100 h long-term test at 400 °C in CO methanation. The electron enrichment of Ni and Co of homogeneous alloy contributes to CO dissociation, hydrogen spillover, and CO2 adsorption, which facilitates CH4 formation and the removal of deposited carbon species. This work provides a new clue for fabricating bimetallic catalysts and revealing the relationship between the fine structure of Ni-Co alloy and their catalytic performances.