Design of catalyst for syngas conversion to C2 oxygenates via confining diatomic metal within the framework of 2D carbon-based materials

The selectivity of syngas-to-C2 oxygenates still faces a big challenge. In the present study, the different 2D carbon-based substrates (g-C3N4, GDY and C2N) supported diatomic RhCo catalysts are constructed reasonably to enhance C2 oxygenates selectivity. The complicated reaction network is studied by means of DFT calculations; the influences of the species coverage, the reaction temperature and pressure are examined using microkinetic modeling. The results indicate that RhCo/g-C3N4, RhCo/GDY and RhCo/C2N catalysts have excellent structural stability. The preferred existence form of CHx(x = 1-3) monomer, as well as the activity and selectivity of CHx monomer and C2 oxygenates generation are strongly related to the coordination environment of 2D carbon-based material supported diatomic RhCo catalysts. The screened RhCo/g-C3N4 catalyst could perform the outstanding catalytic performance toward the generation of C2 oxygenates CH2CO and CH3CO, in which the coordination environment of g-C3N4 makes the diatomic RhCo cluster lose more electron and d-band center far away from Fermi level. This work provides an alternative way to construct 2D substrate supported diatomic metal catalysts in syngas-to-C2 oxygenates, adjusting 2D substrate type could change the local coordination environment of diatomic metal sites and further improve catalytic performance.

Automated summary

In this study, different 2D carbon-based substrates were used to support diatomic RhCo catalysts to improve the selectivity of C2 oxygenates in syngas conversion. The reaction network was analyzed using DFT calculations and the influences of species coverage, temperature, and pressure were investigated through microkinetic modeling. The results showed that the supported catalysts had excellent structural stability and the coordination environment of the carbon-based substrate strongly influenced the activity and selectivity of C2 oxygenates generation. The RhCo/g-C3N4 catalyst exhibited outstanding performance, with the coordination environment of g-C3N4 leading to the loss of more electrons and a shift in the d-band center, resulting in increased C2 oxygenates production.