Dichotomizing the Oxygen Electrocatalytic Properties of Doped Carbon Catalysts in Acid through a Salt-Activated Synthesis

摘要

The dearth of acidproof non-platinum group metal (PGM) catalysts for the oxygen evolution reaction (OER) in a low pH environment has been the greatest challenge in the development of aqueous rechargeable acid metal-air batteries, which are free from the electrolyte carbonation problem of alkaline batteries. Carbon-based catalysts by far form the largest group of non-PGM oxygen electrocatalysts. The performance of carbon catalysts in the oxygen reduction reaction (ORR) can be improved by using a salt-activated synthesis. This method, however, is not applied to improve the catalytic performance of carbon in the OER. In view of the very different reaction micro-environments for the ORR and OER, the carbon active sites for the ORR and OER are expected to be mutually exclusive. Is it then possible to switch between the ORR and OER properties of carbon-based catalysts by using salts with different chemical labilities in a salt-activated synthesis? This communication is a report of our investigation of the effects of lithium salts on the microstructure and performance of doped carbon catalysts in oxygen electrocatalysis in acid.