Surface engineering of flower-like Co-N-C on carbon paper for improved overall water splitting

Abstract

Designing efficient non-precious metal catalysts with superior activity and stability for water splitting has been the pursuit of researchers. The purpose of this work is to investigate the influence of 2-amino terephthalic acid on the surface engineering of flower-like Co-N-C for improved water splitting in an alkaline solution. The flower-like Co-N-C grown on carbon paper (Co-N-C/CP) were fabricated by a facile hydrothermal and subsequent annealing process. When the ratio of Co2+ and 2-amino terephthalic acid reaches 1:2 in the precursors, the resultant Co-N-C/CP exhibits the overpotential of 181 mV and 290 mV at 10 mV cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Furthermore, the Co-N-C/CP (1:2)||Co-N-C/CP(1:2) water splitting systems deliver a current density of 10 mA cm−2 at 1.56 V. After 1500 cycles, the required voltage for water splitting still maintains at 1.57 V. The outstanding electrocatalytic properties are attributed to the tuning electron structure on the surface of Co-N-C, which promotes the charge transfer and chemical mass transport during water splitting in an alkaline solution. This study provides a new opportunity to develop highly efficient cobalt-based catalysts for enhanced water splitting.