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

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. © Tsinghua University Press 2023.