Phosphorus-doped binary Ni/Fe-nitrogen-carbon material for enhanced oxygen electrocatalysis

Adjusting the micro-environment of atomically dispersed metals on carbon supports has been proved to be effective for the obtainment of enhanced electrocatalysis performance. Herein, we delicately designed a phosphorus-doped binary NiFe-nitrogen-carbon material (denoted as P-NiFe-NC) taking advantage of the coupling reaction between phenylphosphonamide (P dopant) and formamide (the carbon and nitrogen source). XPS N 1s fine scan suggests the strong interplay of N and P by the positively shifted binding energy of pyridinic N species after P incorporation, and further the chemical state of Fe species has been influenced. The P-NiFe-NC sample exhibits very good bifunctional oxygen electrocatalysis performance, rendering an ORR half-wave potential of 0.85 V (vs. RHE) and an OER potential of 1.69 V to reach a current density of 10.0 mA cm−2, superior to those of P-free NiFe-NC. Assembled into Zn-air battery, the P-NiFe-NC delivers a large specific power of 161.36 mW cm−2 and is capable of stably charge/discharge for over 100 h (corresponding to 300 cycles).