Institute of Advanced Studies (IAS), College of Chemistry and Molecular Sciences , Wuhan University , Wuhan 430072 , Hubei , P. R. China.
ACS Appl Mater Interfaces. 2018 Jul 25;10(29):24715-24724. doi: 10.1021/acsami.8b06165. Epub 2018 Jul 13.
Low-cost transition metal oxides are actively explored as alternative materials to precious metal-based electrocatalysts for the challenging multistep oxygen evolution reaction (OER). We utilized the Kirkendall effect allowing the formation of hollow polycrystalline, highly disordered nanoparticles (NPs) to synthesize highly active binary metal oxide OER electrocatalysts in alkali media. Two synthetic strategies were applied to achieve compositional control in binary transition metal oxide hollow NPs. The first strategy is capitalized on the oxidation of transition-metal NP seeds in the presence of other transition-metal cations. Oxidation of Fe NPs treated with Ni (+2) cations allowed the synthesis of hollow oxide NPs with a 1-4.7 Ni-to-Fe ratio via an oxidation-induced doping mechanism. Hollow Fe-Ni oxide NPs also reached a current density of 10 mA/cm at 0.30 V overpotential. The second strategy is based on the direct oxidation of iron-cobalt alloy NPs which allows the synthesis of hollow Fe Co-oxide NPs where x can be tuned in the range between 36 and 100. Hollow FeCo-oxide NPs also revealed the current density of 10 mA/cm at 0.30 V overpotential in 0.1 M KOH.
低成本过渡金属氧化物作为替代贵金属基电催化剂的材料，被积极探索用于具有挑战性的多步骤析氧反应（OER）。我们利用 Kirkendall 效应，使多晶、高度无序的纳米颗粒（NPs）空心化，在碱性介质中合成了高活性的二元金属氧化物 OER 电催化剂。采用了两种合成策略来实现二元过渡金属氧化物空心 NPs 的组成控制。第一种策略是利用过渡金属 NP 种子在存在其他过渡金属阳离子的情况下的氧化来实现。用 Ni(+2)阳离子处理的 Fe NPs 的氧化允许通过氧化诱导掺杂机制合成具有 1-4.7 的 Ni 与 Fe 比的空心氧化物 NPs。空心 Fe-Ni 氧化物 NPs 在 0.30 V 过电势下也达到了 10 mA/cm 的电流密度。第二种策略基于铁钴合金 NPs 的直接氧化，允许合成空心 FeCo-氧化物 NPs，其中 x 可以在 36 到 100 之间调节。空心 FeCo-氧化物 NPs 在 0.1 M KOH 中也在 0.30 V 过电势下达到了 10 mA/cm 的电流密度。
