载镍铁双金属微纳米纤维的构筑及其氧催化性能

Construction of nickel and iron bimetal decorated micro-nanofibers and their oxygen catalytic properties

开发高效的非贵金属氧还原/氧析出(oxygen reduction/evolution reaction,ORR/OER)双功能电催化剂对发展锌空气电池(zinc air batteries,ZABs)至关重要。文章以载有镍(Ni)、铁(Fe)金属的有机框架化合物为母体,利用静电纺丝技术制备了多级结构微纳米纤维,后经高温碳化,获得载有Ni、Fe双金属的微纳米碳纤维催化剂。探究了金属类型及负载方式对催化剂的ORR和OER催化性能的影响,结果表明:Ni和Fe之间的协同作用能够有效增强Ni基催化剂的OER催化活性,但Ni的引入会抑制Fe基催化剂的ORR催化活性。通过分步负载法使得Ni和Fe金属原子分离锚定时制备得到的纤维催化剂(Ni@PCF-Fe),具有较好的ORR/OER双功能催化性能:ORR半波电位为0.793 V(vs.RHE),OER在10 mA/cm^(2)电流密度时的电位为1.590 V。以Ni@PCF-Fe与氧化钌(RuO2)为正极催化剂组装的ZABs具有较好的电化学储能性能:开路电压为1.43 V,功率密度为108.48 mW/cm^(2)。

The development of highly efficient non-noble metal bifunctional electrocatalysts for oxygen reduction/evolution reaction(ORR/OER)is critical for zinc air batteries(ZABs).In this study,hierarchical micro-nanofibers containing nickel(Ni)and iron(Fe)decorated metal-organic frameworks were prepared using electrospinning.These micro-nanofibers were then subjected to high-temperature carbonization,resulting in Ni and Fe anchored porous carbon fibers.The effects of metal types and loading methods on the ORR and OER performance of the carbon fibers were investigated.The results show that the synergistic effect between Ni and Fe can effectively enhance the OER catalytic activity of Ni-based catalysts,but the presence of Ni inhibits the ORR catalytic activity of Fe-based catalysts.By employing a stepwise loading method to spatially confine and separately anchor Ni and Fe atoms,the resulting fiber catalyst(Ni@PCF-Fe)exhibits excellent bifunctional catalytic performance:a half-wave potential of 0.793 V(vs.RHE)for ORR and a potential of 1.590 V at a current density of 10 mA/cm^(2)for OER.The ZABs assembled with Ni@PCF-Fe and RuO2 as air cathode catalysts demonstrate good electrochemical energy storage performance,with an open circuit voltage of 1.43 V and a peak power density of 108.48 mW/cm^(2).