Strategy for improving acetylene hydrogenation by synergistic effects between carbon coated bimetallic nanoparticles

The semi-hydrogenation of acetylene represents a crucial industrial process, with the catalytic conversion of trace acetylene in ethylene-rich streams, achieved without pretreatment, offering a greener and more sustainable approach. A bimetallic NiCo@C catalyst was synthesized through the pyrolysis of a metal-organic framework (MOF) precursor. During pyrolysis, the organic ligands form a uniform carbon layer, effectively protecting the metallic active sites formed. This process yields alloy nanoparticle catalysts characterized by a high surface area and a complete carbon layer. The formation of the NiCo alloy facilitates a geometric isolation of Ni by Co, coupled with electronic modification, which ensures high selectivity for conversion. In addition, the outer carbon layer preserves elements of the original MOF spatial structure, exhibiting a high specific surface area and dispersion, thus enabling the rapid desorption of ethylene post-reaction. Density functional theory (DFT) calculations were employed to explain the semi-hydrogenation mechanism of acetylene on the carbon-layered NiCo alloy. In a flow reactor designed for acetylene hydrogenation, the combination of bimetallic interaction and carbon layer protection produced a catalyst conversion rate of 95 % and a selectivity of 83 %. In conclusion, the NiCo alloy, effectively shielded by the carbon layer derived from the organic ligands during pyrolysis, exhibits enhanced catalytic performance due to the interaction of the bimetallic components.