Highly dispersed Co atoms anchored in porous nitrogen-doped carbon for acidic H2O2 electrosynthesis

Abstract

Cobalt–nitrogen–carbon (Co–N–C) materials exhibit great potential for H2O2 electrosynthesis through the oxygen reduction reaction (ORR). However, the encapsulated Co nanoparticles reduce the Faradic efficiency of H2O2 production. Herein, highly dispersed cobalt atoms anchored in porous N-doped carbon (p–Co–N–C) via a carbonization-alkalization-acidification strategy are prepared and prove to be efficient for H2O2 electrosynthesis in acidic media. The H2O2 selectivity on the p–Co–N–C is over 90%, which is three times higher than that of Co nanoparticles encapsulated in N-doped carbon. Notably, the p–Co–N–C displays a H2O2 production rate of 2,460.8 mg L−1h−1 and a malachite green degradation rate of 90% within 8 min when employed in a flow cell. The enhanced performance of p–Co–N–C for H2O2 electrosynthesis originates from the highly dispersed Co–Nx species and hierarchical porous architecture. The Co–Nx species can provide active sites for O2 and reaction intermediate adsorption and the hierarchical porous architecture can promote the diffusion of H2O2 into the bulk solution. This work provides a facile synthesis strategy for non-precious metal materials in various energy-related applications.