The New Role of Pivotal Intermediate Chx in Co Activation and Conversion to Hydrocarbons on the Transition Metal Catalysts

The pivotal intermediate CHx(x=1-3) are commonly regarded as the reaction species involving in the conversion of syngas to hydrocarbons over the Co- and Ni-based catalysts. Here the DFT calculations and microkinetic modeling are employed. This work illustrates the new mechanism of CHx(x=1-3) adsorbed over Co catalyst (CHx(x=1-3)/Co) to catalyze syngas-to-hydrocarbon for the first time, the preferred CHx(x=1-3) is CH monomer over the Co and CHx(x=1-3)/Co catalysts, the produced CH not only participates into the reactions as the reactive intermediate, but also performs the role of surface assist to enhance the activity and selectivity toward CHx(x=1-3) and C2 hydrocarbons. The uniquely electronic micro-environment under the assist of CHx(x=1-3) over Co catalyst are clarified. Interestingly, the same things also occur in CO methanation over CHx(x=1-3)/Ni catalysts, which is highly active and selective toward methane. Thus, the new mechanism of CHx(x=1-3) intermediate as the catalytic assist located over the transition metal may be popularized in the other reaction systems mentioned CHx(x=1-3) intermediate