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

A novel 2D Co-MOFs-based growth-sulfidation-phosphorization approach is developed to fabricate integrated Co-S-P hollow nanosheet arrays on carbon cloth substrate, which displays superior electrocatalytic properties for overall water splitting. • Integrated Co-S-P hollow nanoarrays is fabricated by a facile 2D Co-MOFs-based growth-sulfidation-phosphorization approach. • The Co-S-P hollow nanoarrays exhibit excellent electrocatalytic activity toward OER, HER, and overall water splitting. • DFT calculations reveal that P-anions doping into CoS 2 leads to moderated adsorption energetics of OER and HER intermediates. 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-CoS 2 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-CoS 2 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 IrO 2 /CC || Pt/C/CC couple (1.55 V). Density functional theory (DFT) calculations demonstrate that decoration of P-anions into CoS 2 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-CoS 2 HNA/CC. This work may shed some new light on the design of advanced and high-active electrocatalysts for overall water splitting. [ABSTRACT FROM AUTHOR]