Hollow nanosheet array of phosphorus-anion-decorated cobalt disulfide as an efficient electrocatalyst for overall water splitting

Abstract The development of economical and versatile catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is an exceedingly challenge for hydrogen production from water electrolysis. Herein, three-dimensional (3D) phosphorus-anion-decorated cobalt disulfide hollow nanosheet arrays are uniformly deposited on carbon cloth (P-CoS2 HNA/CC) through a MOF-based growth-sulfidation-phosphorization approach. Benefiting from the moderated electronic structure, maximum exposure of active surface sites and the unique 3D hollow conductive architecture, the optimal P-CoS2 HNA/CC delivers superior electrocatalytic activity with extremely low overpotentials of 250 and 80 mV to achieve a current density of 10 mA cm−2 for OER and HER in alkaline conditions, respectively. The corresponding two-electrode electrolyzer for overall water splitting requires a cell voltage of 1.56 V to attain a current density of 10 mA cm−2, close to commercial IrO2/CC || Pt/C/CC couple (1.55 V). Density functional theory (DFT) calculations demonstrate that decoration of P-anions into CoS2 electrocatalysts not only significantly tunes adsorption energetics of H- and O-containing intermediates, but also offers additional active sites for OER/HER process, dramatically boosting the catalytic activity of P-CoS2 HNA/CC. This work may shed some new light on the design of advanced and high-active electrocatalysts for overall water splitting.