Nickel Phosphonate MOF Derived N‐doped Carbon‐coated Phosphorus‐vacancies‐rich Ni2P Particles as Efficient Bifunctional Oxygen Electrocatalyst

The design of non-noble metal bifunctional electrocatalysts with outstanding performance and remarkable stability for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is the most essential issue to the realization of rechargeable zinc-air battery and transition metal phosphides (TMPs) have emerged as robust candidates for oxygen electrocatalysts. Herein, N-doped carbon-coated phosphorus-vacancies-rich Ni2P particles (Vp-Ni2P@NC) is proposed via simple carbonization and following Ar plasma treatment from a single nickel phosphonate metal organic framework (MOF) without extra phosphine and nitrogen sources. The facile and rapid plasma treatment can achieve phosphorus vacancies which could modulate the electronic structure to enhance the inherent active and electrical conductivity. Meanwhile, the pyridine-N and graphitized-N produced during calcination also could provide more active sites and increase the electrical conductivity. The resultant Vp-Ni2P@NC catalyst shows excellent bifunctional electrocatalytic activity (OER/ORR) based on synergistic effect of introducing P vacancies into Ni2P and N-doped carbon. Vp-Ni2P@NC catalyst shows more advantageous ΔE value (0.70 V) compared to Pt/C + RuO2 (0.73 V) and most reported catalysts. Additionally, the Zinc-Air Batterie (ZAB) employing Vp-Ni2P@NC as air cathode shows excellent performance. The maximum power density of 203.48 mW cm−2, the cycling stability of more than 150 h at 10 mA cm−2.