Biomass-derived porous carbon supported Co-CoO yolk-shell nanoparticles as enhanced multifunctional electrocatalysts

Developing highly efficient, durable and low-cost electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in energy conversion and storage is still required, urgent and challenging. Herein, a novel structure of biomass-derived nitrogen-doped porous carbon supported yolk-shell Co-CoO nanoparticles (yolk-shell Co-CoO/BC) was successfully prepared via a facile impregnation strategy. The pyrolysis temperature and heating rate of Co2+/BC composite are two key factors in the formation of the yolk-shell structure. The synthesized yolk-shell Co-CoO/BC exhibits excellent electrochemical activity and stability as multifunctional electrocatalysts. The yolk-shell Co-CoO/C with a positive onset potential (0.91 V vs. RHE) and half-wave potential (0.82 V vs. RHE) exhibits an effective 4-electron transfer path and excellent methanol tolerance in alkaline electrolyte for ORR. Moreover, a low cell potential (eta(10) = 1.77 V vs. RHE at the current density of 10 mA cm(-2)) for overall water splitting can be reached. The synergistic catalytic effects between BC support and yolk-shell Co-CoO nanoparticles should be responsible for the excellent performance for ORR, OER and HER. This work opens up a way to the facile fabrication of carbon supported yolk-shell nano structures with high-performance in electrocatalytic applications for ORR, OER and HER. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.