Coordination confinement pyrolysis to hollow sea urchin shaped composite with embedded ultrasmall Co/Ni alloy for overall water splitting

Electrocatalytic water splitting has been extensively studied for producing clean fuels in energy conversion and utilization. However, the huge challenge is remaining existence for developing efficient and low-cost non-noble metal electrocatalysts. Herein, an efficient hollow sea urchin-shaped water-splitting catalyst was prepared by coordination confinement pyrolysis strategy, in which the superminiature Co/Ni alloy (ca. 5 nm) was embedded into the nanorods assembly unit successfully. This as-synthesized catalyst not only reveals satisfactory catalytic efficiencies with 70 and 296 mV overpotentials for HER and OER at the current density of 10 mA cm−2, but also demonstrates the total stabilities for HER, OER, and over water splitting after long-term electrolytic process with the negligible potentials increase by 2.8%, 2.9%, and 1.8%. Therefore, the catalyst integrates the advantages of superminiature Co/Ni alloy particles, hollow structure, and slender nanorods, which could provide a new route to design and prepare other efficient electrocatalysts.