Interface transformation strategy to 1D hierarchically porous carbon with enhanced bifunctional oxygen electrocatalytic performance

Abstract

Developing efficient oxygen electrocatalysts is considered a key step to advancing renewable energy technologies, especially in fuel cells and metal-air batteries. Herein, an interface transformation strategy is proposed to prepare a one-dimensional cobalt (Co)/nitrogen (N) co-doped porous carbon material (Co/N-PCM). Polydopamine nanotubes (PDA NT) and cobalt phthalocyanine (CoPc) were used as precursors for the controlled formation of Co/N-PCM. Immobilized CoPc molecules on PDA NT formed Co/N-PCM with evenly distributed Co/ Co-N-C sites and a hierarchical micro-/mesoporous structure. Theoretical calculations revealed that the electronic modulation of the substrate by Co(1 1 1) played a pivotal role in establishing the d-band center of active Co sites on the monatomic Co-N-C layer. The surface-active Co sites provided an optimum adsorption strength between the Co/N-PCM and oxygenated intermediates, leading to significantly enhanced intrinsic oxygen reduction/evolution reaction (ORR/OER) activities. The engineered Co/N-PCM catalyst displayed high activity towards bifunctional oxygen electrocatalysis and delivered outstanding rechargeable zinc-air battery (ZAB) performance.