Direct Spectroscopy for Probing the Critical Role of Partial Covalency in Oxygen Reduction Reaction for Cobalt-Manganese Spinel Oxides.

ABSTRACT: Nanocrystalline multivalent metal spinels are considered as attractive non-precious oxygen electrocatalysts. Identifying their active sites and understanding their reaction mechanisms are essential to explore novel transition metal (TM) oxides catalysts and further promote their catalytic efficiency. Here we report a systematic investigation, by means of soft X-ray absorption spectroscopy (sXAS), on cubic and tetragonal Co_xMn_3-xO₄ (x = 1, 1.5, 2) spinel oxides as a family of highly active catalysts for the oxygen reduction reaction (ORR). We demonstrate that the ORR activity for oxide catalysts primarily correlates to the partial covalency of between O 2p orbital with Mn⁴⁺ 3d t_2g-down/e_g-up, Mn³⁺ 3d e_g-up and Co

SUBMITTER: Long X 

PROVIDER: S-EPMC6523907 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature