Stainless steel mesh based CoNiSe4/CoNi-layered-double-hydroxides for efficient water-splitting and durable Zn-air battery

Design catalyst with excellent oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) activities applied for both water splitting and Zn-air battery (ZAB) remain a challenge. Herein, we synthesized the stainless steel mesh (SSM) based self-supported CoNiSe4/CoNi-layered-double-hy- droxides (CoNiSe4/CoNi-LDH) through one-step hydrothermal course and the other step of controllable selenization process. The formed CoNiSe4/CoNi-LDH/SSM displays much enhanced OER, HER and ORR properties than that of the CoNi-LDH/SSM. Additionally, ZAB assembled with CoNiSe4/CoNi-LDH/SSM as air-cathode delivers over than 800 h long-life charging-discharging property and with much lower voltage gap of 0.826 V, superior than that assembled with CoNi-LDH/SSM precursor (approximate to 350 h, 0.850 V), or even the commercial Pt/C + RuO2/SSM (approximate to 120 h, 0.840 V), respectively. After analyzing the insight influence of the surface selenization, we conclude that the in-situ formed CoNiSe4/CoNi-LDH heterojunction shortens the electron transfer during the catalytic process, which maximizes the synergy electrocatalytic effect between CoNiSe4 and CoNi-LDH. Hence, the directly surface selenization finally results in the achieved CoNiSe4/CoNi-LDH/SSM a superior trifunctional catalyst. This work not only provides an efficient performance optimization strategy, but will also be the experimental/theoretical foundation to other metal-LDH based catalysts.