Density functional theory calculation of two-dimensional transition metal–hexaiminotriphenylene (TM-HITP) electrocatalytic CO2 reduction†

Abstract

Carbon dioxide reduction technology can solve the shortage of resources and climate issues like “warming of the planet”. Metal–organic frameworks (MOFs) contain well-defined active sites, a huge specific surface, and a robust porous structure, making them a good candidate for use in CO₂ electrocatalytic reduction. Using the principles of spin-polarization density functional theory, the two-dimensional MOF constructed from transition metal–hexaiminotriphenylene was calculated to reduce CO₂ electrocatalytically. The results show that for ten transition metal (TM-HITP) two-dimensional network structures spanning Sc through Zn, the formation energies E_f are all negative, and they can theoretically be synthesised experimentally, and the metal atoms can be disseminated in the HITP framework steadily because their binding energies to HITP are highly sufficient. Considering the competition with the HER, all catalysts showed CO₂RR selectivity except Co-HITP. Co-HITP catalysts required pH >7.22 to show CO₂RR selectivity. The main products and overpotentials of both Fe and Co catalysts were in agreement with the available literature values, indicating that the calculations were reliable. HCOOH is the primary product for Sc, Ni, and Cu. The principal product of Ti and V is CH₄. CH₃OH is the primary product for Cr, Fe, and Co. The product selectivity of Mn was poor and three products, CH₄, HCHO and HCOOH, were obtained simultaneously at the same limiting potential. The limiting potentials of these ten catalysts for electrocatalytic CO₂ reduction ranged from 0.296 to 0.738 volts and the overpotentials between 0.027 V and 0.754 V, all of which were rather little. Consequently, we forecast that the two-dimensional MOFs constructed with transition metals with hexaiminotriphenylene are potential electrocatalysts for CO₂ reduction because they demonstrate excellent catalytic activity in the electrocatalytic reduction of CO₂.