Heterointerface engineering of assembled CoP2 on N-modified carbon as efficient trifunctional electrocatalysts for Zn-Air batteries and overall water splitting

Abstract

Enhancing catalytic activity through modulating the interaction between N-doped carbon and metal phosphides clusters is an effective approach. Herein, the electronic structure modulation of CoP2 supported N-modified carbon (CoP2/NC) has been designed and prepared as efficient electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Notably, CoP2/NC-1 catalyst exhibits impressive performance in alkaline media, with an ORR half-wave potential of 0.84 V, as well as OER and HER overpotentials of 290 and 129 mV (at 10 mA·cm−2), respectively. In addition, CoP2/NC-1 produces a power density as high as 172.9 mW·cm−2, and excellent reversibility of 100 h at 20 mA·cm−2 in home-made Zn-air batteries. The experimental results demonstrate that the synergistic interactions between N modified carbon substrate and CoP2 material significantly enhance the kinetics of ORR, OER, and HER. Density functional theory (DFT) calculations reveal the strong electrons redistribution of CoP2 induced by high-density N atoms at the interface, thus optimizing the key intermediates and significantly lower the energy barrier of reactions. These electronic adjustments of CoP2 greatly enhance its kinetics of ORR/OER/HER, leading to faster reactions. This study provides profound insights into the specific modification of CoP2 by N-doped carbon, enabling the construction of efficient catalysts.