CoFeP hierarchical nanoarrays supported on nitrogen-doped carbon nanofiber as efficient electrocatalyst for water splitting.

Developing high-efficient bifunctional electrocatalysts is significant for the overall water splitting. Bimetallic phosphides show great potential for the bifunctional hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysts due to the excellent catalytic performance. Herein, the CoFeP two-dimensional nanoarrays successfully grown on nitrogen doped electrospun carbon nanofibers (CoFeP NS@NCNF) through template-directed growth and following phosphorization treatment. Benefiting from the hierarchical nanoarrays structure, synergistic effect of high electrical conductivity carbon nanofiber substrate and bimetallic phosphide, the CoFeP NS@NCNF exhibits efficient bifunctional electrocatalytic activities for OER and HER in 1 M KOH with overpotentials of 268 mV (η) and 113 mV (η), respectively. Moreover, the CoFeP NS@NCNF coupled two-electrode system needs a low voltage of 1.59 V at 10 mA cm for overall water splitting. This work provides a promising way for the preparation of transition metal-based electrocatalysts with hierarchical structure derived from Prussian blue analogues (PBAs) for OER and HER.