Porous Fe-Co-P nanowire arrays through alkaline etching as self-supported electrodes for efficient hydrogen production

Abstract

In the present work, an efficient four-step strategy to fabricate the Fe-Co-P porous nanowire arrays in situ grown on a self-supported carbon cloth (denoted as Fe-Co-P/CC) for developing excellent HER activity is reported. The four steps include the preparation of the CoFeZn-precursor by a hydrothermal reaction, the formation of pore-forming agent (ZnO) after annealing treatment, the alkaline etching of ZnO, and phosphorization. Particularly, the alkaline-etched porous Fe-Co-P nanowire-arrays contribute to enhancing the catalytic activity by the exposure of more electrochemical active sites. The as-prepared Fe-Co-P/CC which was prepared by the rational Co-Fe molar ratio, as a binder-free electrocatalyst, shows a high-performance HER with a small overpotential of 121 mV in 1 M KOH and 124 mV in 0.5 M H2SO4 at a current density of 10 mA·cm−2, as well as a good Tafel slope value of 118 mV/dec and 85 mV/dec in alkaline and acid media, respectively, owing to the well-optimized pore-structures and active sites. Additionally, the catalyst almost maintains its electrochemical activity for about 24 and 16 h under alkaline and acidic conditions, respectively. This work provides a new idea for the synthesis of high-efficiency, binder-free electrodes for high-purity hydrogen production.