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Indexed by:期刊论文

Date of Publication:2018-08-09

Journal:JOURNAL OF PHYSICAL CHEMISTRY C

Included Journals:EI、SCIE

Volume:122

Issue:31

Page Number:17812-17819

ISSN No.:1932-7447

Abstract:All 3d transition-metal carbides (3d-TMCs) in the NaCl structure have been constructed to compare the catalytic activities of Li-O-2 batteries by first-principles calculations. The interfacial catalytic models of LixO(2) (x = 4, 2, and 1) molecules adsorbed on 3d-TMC surfaces were used to simulate discharging (oxygen reduction reaction, ORR) and charging (oxygen evolution reaction, OER) processes. The calculated results indicate that the TiC surface has smaller ORR and OER overpotentials, which may be due to the maximum catalytic activity of 3d-TMCs. Taking overpotentials as the measurement of catalytic activity, some intrinsic properties related to catalytic activity are determined, including adsorption energies of Li and LiO2, surface energy, and binding energy of O. The catalytic activities of 3d-TMCs for ORR and OER are inversely proportional to the adsorption energies of Li and LiO2. The ORR overpotentials are proportional to the surface energies of 3d-TMC surfaces, but the relationship between OER overpotentials and the surface energies is not clear. TiC has a moderate binding energy of O atom. Additionally, when the bonding state tends to be saturated, namely, Fermi level happens to be in pseudogap, the catalytic activity reaches its maximum. By calculating ORR and OER overpotentials and establishing the correlation between catalytic activity and relevantly the intrinsic properties of 3d-TMCs, our investigation is helpful for screening and designing highly active catalysts to enhance ORR and OER in Li-O-2 batteries.