Hierarchical iron-doped CoP heterostructures self-assembled on copper foam as a bifunctional electrocatalyst for efficient overall water splitting

A bifunctional electrocatalyst with peculiarly hierarchical snowflake-like iron-doped CoP heterostructures self-assembled on copper foam (CoFeP/CF) was synthesized via a facile hydrothermal-phosphidation pathway. The excellent electrochemical performance of CoFeP/CF can be attributed to the synergistic effect of cobalt and iron atoms, tuneful interaction between metal atoms and phosphorus, and the large electrochemical active surface area origined from its peculiarly hierarchical snowflake-like heterostructures with high surface roughness. With the small Tafel slope values (of 73.0 mV dec−1 for OER and 90.4 mV dec−1 for HER), CoFeP/CF demands the diminutive overpotentials (of 277.9 mV for OER and 152.6 mV for HER) to desire the current density of 50 mA cm−2 in alkaline electrolyte. Furthermore, CoFeP/CF exhibits outstanding electrochemical performance for the overall water splitting with the cell potential of 1.495 V to attain 10 mA cm−2 in a two-electrode cell.