摘要
The exploration of cheap,efficient,and durable bifunctional electrocatalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is highly desired to push forward the commercialization of rechargeable metal–air batteries.Here,bifunctional ORR/OER electrocatalysts based on CoxP(0<x<2,i.e.,Co_(2)P,Co_(2)P/CoP mixture,and CoP)nanoparticles(NPs)anchored on N,P-doped carbon framework(Co_(x)P@NPC)are developed via one-step carbonization of the mixture of as-synthesized ZIF-67 and melamine–phytic acid supermolecular aggregate(MPSA).The stoichiometric ratio of resultant Co_(x)P NPs can be rationally designed by adjusting the introduced ratio of ZIF-67 to MPSA,enabling their fabrication in a controlled manner.It is found that the as-synthesized Co_(2)P@NPC exhibits the best bifunctional ORR/OER activity among the Co_(x)P@NPC analogues,with a reversible oxygen electrode index(ΔE=E_(j10)−E_(1/2))down to~0.75 V.The constructed Zn–air battery based on Co_(2)P@NPC delivers a peak power density of 157 mW cm^(−2) and an excellent charge-discharge stability with negligible voltage decay for 140 h at 10 mA cm^(−2),superior to those based on Pt/C+RuO_(2) and most Co_(x)P-based electrodes ever reported.
基金
supported by National Natural Science Foundation of China(NSFC,Grant Nos.51702176,51572133,and 51972178)
Zhejiang Provincial Nature Science Foundation(Grant No.LY20E020009)。
