Metallophthalocyanine-Based Polymer-Derived Co2P Nanoparticles Anchoring on Doped Graphene as High-Efficient Trifunctional Electrocatalyst for Zn-Air Batteries and Water Splitting

Covalent organic polymers (COPs) provide an interesting platform for constructing the low-cost and highly efficient multifunctional electrocatalysts in view of their tailorable structures and properties. Herein, Co-phthalocyanine-based COPs (CoPc-COPs) are constructed using cobalt tetraaminophthalocyanine (CoPc(NH2)4) as the organic building unit and phosphonitrilic chloride trimer (Cl6N3P3) as the linker group, which serve as the self-carrier enriched with Co, P, N, and C to derive Co2P nanoparticles anchored on the N, P codoped graphene after carbonization treatment. Benefiting from the unique construction and the metallic property confirmed by density functional theory (DFT) calculations, the Co2P/NPG displays high-efficient trifunctional electrocatalytic performance toward oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER), including excellent oxygen electrocatalytic activity (overpotential of 0.32 V at 10 mA cm–2 for OER, half-wave potential of 0.81 V for ORR) and outstanding stability (98% over 12 h for OER, 89% over 17 h for ORR). Impressively, rechargeable Zn-air batteries (ZABs) that employed Co2P/NPG as the cathode electro-catalyst display a peak power of up to 103.5 mW cm–2 along with a good cycle stability after 55 h. Moreover, the constructed ZABs can be used to power the overall water splitting. Therefore, function-oriented design of metallophthalocyanine-based COPs provides new ways to strategically construct multifunctional electrocatalysts for the wider integrated green energy system.