Promoting Active Sites in Core–Shell Nanowire Array as Mott–Schottky Electrocatalysts for Efficient and Stable Overall Water Splitting

Abstract

AbstractDeveloping earth‐abundant, active, and robust electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a vital challenge for efficient conversion of sustainable energy sources. Herein, metal–semiconductor hybrids are reported with metallic nanoalloys on various defective oxide nanowire arrays (Cu/CuOx, Co/CoOx, and CuCo/CuCoOx) as typical Mott–Schottky electrocatalysts. To build the highway of continuous electron transport between metals and semiconductors, nitrogen‐doped carbon (NC) has been implanted on metal–semiconductor nanowire array as core–shell conductive architecture. As expected, NC/CuCo/CuCoOx nanowires arrays, as integrated Mott–Schottky electrocatalysts, present an overpotential of 112 mV at 10 mA cm−2 and a low Tafel slope of 55 mV dec−1 for HER, simultaneously delivering an overpotential of 190 mV at 10 mA cm−2 for OER. Most importantly, NC/CuCo/CuCoOx architectures, as both the anode and the cathode for overall water splitting, exhibit a current density of 10 mA cm−2 at a cell voltage of 1.53 V with excellent stability due to high conductivity, large active surface area, abundant active sites, and the continuous electron transport from prominent synergetic effect among metal, semiconductor, and nitrogen‐doped carbon. This work represents an avenue to design and develop efficient and stable Mott–Schottky bifunctional electrocatalysts for promising energy conversion.