Porous Co2P film coated on carbon fiber as highly performance electrocatalyst toward overall water splitting

Abstract

Designing porous active materials and enhancing their contact with conductive substrates is an effective strategy to improve electrolytic water splitting performance of noble metal-free catalysts. Herein, a facile nanostructured electrode, composed of porous Co2P films coated on carbon fiber (CF@P–Co2P), is designed and prepared. The unique three-dimensional interconnected pore structure of Co2P and the close contact between porous Co2P and CF not only increase specific surface areas to expose abundant catalytic sites but also stimulate the transport of electron, mass and gaseous products in catalytic process. Benefit from the reasonable electrode structure, the self-supported CF@P–Co2P electrodes present perfect performance with only needing overpotentials of 107.7/175.5/141.8 mV for hydrogen evolution reaction (HER) in acidic/neutral/alkaline solution and 269.4 mV for oxygen evolution reaction (OER) in alkaline solution to get current density of 20 mA cm−2. In addition, alkaline electrolyzer equipped with CF@P–Co2P bifunctional electrodes only needs a cell voltage of 1.657 V to get water-splitting current density of 20 mA cm−2. Even better, the electrolyzer can continuously electrolyze over 50 h with negligibly decreasing current density and the Faraday efficiency is close to 100% toward both HER and OER.