Synergistic effect of bimetallic nitride micro-flower promotes highly efficient overall water splitting

Abstract

Developing efficient, low-cost, high-active, and durable bifunctional non-noble metal electrocatalysts is an essential requirement for hydrolytic hydrogen production. In this work, a three-dimensional (3D) flower-like bimetallic nitride (Co2NiN) is synthesized on the flexible carbon cloth (CC) that increases the surface area and exposes more active sites. At the same time, the synergistic effect between Ni3N, CoN and Co increases the electron transfer rate and optimizes the binding energy of intermediate products. The Co2NiN/CC electrode is superhydrophilic and superaerophobic, which guarantees intimate contact with the electrolyte and promotes timely the bubble release from the electrode, ensuring a high efficiency and stable working state. Therefore, the Co2NiN/CC electrode exhibits excellent catalytic performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline media. Low overpotentials of only 123 mV and 315 mV are required to achieve the current densities of 10 mA·cm−2 and 20 mA·cm−2 for HER and OER, respectively. For overall water splitting, Co2NiN/CC as both anode and cathode require only 1.457 V for 10 mA·cm−2. This work shows the feasibility and potential of fabricating bimetallic nitrides electrocatalysts.