The Mott-Schottky Co₂P/Co heterocatalyst encapsulated by N,P-doped graphene/carbon nanotubes as high-efficiency trifunctional electrocatalysts for cable-type flexible Zn-air batteries and water splitting

The preparation of highly efficient and low-priced multi-functional electrocatalysts for the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and oxygen evolution reaction (OER) is crucial for robust zinc-air batteries (ZABs) and water electrolyzers. Herein, we report the preparation of novel Mott-Schottky Co₂P/Co heterostructures encapsulated by N,P co-doped graphene and carbon nanotubes (Co₂P/Co@N-CNT/NPG) using an in situ pyrolysis strategy, achieving superior trifunctional catalyst performance for the ORR, OER, and HER. The theoretical calculation indicates that the synergistic effect of the Mott-Schottky catalyst could increase the electron transport, trigger the active sites, and enhance the performance toward the ORR/OER. The Co₂P/Co@N-CNT/NPG-based ZAB displays a considerable peak power density of 145 mW cm⁻², and an outstanding cycle-life of 800 h. Furthermore, the flexible ZAB delivers superior mechanical properties with high flexibility, demonstrating its potential feasibility for practical application. Additionally, the water electrolysis device constructed using Co₂P/Co@N-CNT/NPG electrodes requires a small cell voltage of 1.66 V at 10 mA cm⁻², indicating the impressive ability to apply the catalyst for commercial energy storage and harvesting devices.