Well-controlled 3D flower-like CoP3/CeO2/C heterostructures as bifunctional oxygen electrocatalysts for rechargeable Zn-air batteries

Recently, transition metal phosphides (TMPs) have emerged as robust electrocatalysts for rechargeable Zn-air batteries, but their electrocatalytic performance needs further improvements. Herein, well-controlled 3D flower-like CoP3/CeO2/C heterostructures are developed via a pyrolysis-phosphorization strategy, with 3D CeO2 nanoflowers as promoters. The resultant CoP3/CeO2/C heterostructures exhibit high electrocatalytic activity in both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Owing to the large specific surface area and enhanced electrical conductivity, the CoP3/CeO2/C-2 catalyst delivers a small overpotential (339.2 mV at 10 mA cm-2) for the OER and a high half-wave potential for the ORR, which are superior to its counterparts. More importantly, it also demonstrates robust stability in OER and ORR. The CoP3/CeO2/C-2-based rechargeable Zn-air battery yields large power density (150.0 mW cm-2), high energy density (871.3 Wh kgZn- 1), and excellent cycling stability.