Surface reconstruction of hierarchical CoNiP@Ni2P nanoarray to promote overall water splitting

Efficient water splitting remains a challenge to produce clean and pure H2 2 in an industrial scale for the lack of high-performance cost-effective stable electrocatalysts of hydrogen and oxygen evolution (HER and OER). Surface engineering is a novel proposal to upgrade the electrocatalytic performances of HER and OER catalysts. Herein, a hierarchical architecture composed of carbon-supported CoNiP nanoplates (NPs) on Ni2P 2 P nanowire was constructed. The nanoarray of CoNiP@Ni2P 2 P heterostructure shows a high bifunctional activity of HER and OER. The overpotential is 46 mV required for HER at 10 mA & sdot;cm- & sdot; cm- 2 and 292 mV for OER at 100 mA & sdot;cm- & sdot; cm- 2 in 1 mol & sdot;L- 1 & sdot; L- 1 KOH. In addition, the nanoarray of CoNiP@Ni2P 2 P heterostructure also shows a high stability for HER. The HER activity can be maintained at 11 mA & sdot;cm-2 & sdot; cm- 2 without loss after 50 h cathode polarization at the overpotential of 100 mV, while the OER activity continuously increases from 26 to 64 mA & sdot;cm- & sdot; cm- 2 at an overpotential of 400 mV after 50 h anode polarization. The enhancement of the oxygen evolution performance can be ascribed to the surface reconstruction of CoNiP/Ni2P 2 P heterostructure nanoarray, which can offer more active sites to OER. Density functional theory (DFT) reveals surface reconstruction can create an oxygen-rich surface in favor of intermediate adsorption, thus enabling a fast OER kinetics at the interface of NiCoOOH/Ni2P 2 P heterostructure. This work highlights surface reconstruction adaptability to design advanced catalysts of efficient water splitting for commercial H2 2 production.