Dual-coupling ultrasmall iron-Ni2P into P-doped porous carbon sheets assembled CuxS nanobrush arrays for overall water splitting

Abstract

The challenge of simultaneously boosting two half-reactions for overall water splitting using a catalyst with excellent activity, good durability, and cost-effectiveness is still attracting great interest from the scientific community. Herein, a novel electrocatalyst was fabricated via a facile synthesis strategy for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The electrocatalyst was designed by dual-coupling iron and Ni 2 P into P-doped porous carbon (PC) sheets, which were uniformly shelled over one-dimensional copper sulfide (Cu x S) arrays to form a unique nanobrush architecture. The synergistic effects between the iron and ultrasmall Ni 2 P nanoparticles offered a dominant contribution to the catalytic activities with a low required overpotential of 112.9 mV to reach 10 mA cm −2 for the HER and 330 mV to reach 50 mA cm −2 for the OER, superior to bare Cu x S and Ni 2 P@PC/Cu x S. An electrolyzer cell originated from Fe-Ni 2 P@PC/Cu x S electrodes required a small cell voltage of 1.62 V at a current response of 10 mA cm −2 , which even interestingly surpassed recently reported ones. The excellent performance of the proposed Fe–Ni 2 P@PC/Cu x S material made it an innovative bifunctional candidate for overall water splitting applications. • Fe-Ni 2 P dual-coupled P-doped carbon nanosheets supported Cu x S arrays is prepared. • The hybrid catalyst exhibits good activities toward both HER and OER in 1.0 M KOH. • The hybrid-based electrolyzer delivers a cell voltage of 1.62 V at 10 mA cm −2 . • The hybrid-based electrolyzer achieves good stability and durability in 1.0 M KOH.