氧空位和磷掺杂协同增强铁钴基材料电解水催化性能

Synergistic enhancement of catalytic water electrolysis performance of iron-cobalt-based materials by oxygen vacancies and phosphorus doping

为了研发高效、稳定的电解水催化剂,我们以氧空位和磷掺杂为基础,通过原位浸泡生长和两步热处理的方法,在泡沫铁上合成具有氧空位和磷掺杂的纳米花结构作为析氢反应(HER)和析氧反应(OER)双功能电催化剂。CoFe_(2)O_(4)已被报道为一种很有前途的OER和氧还原反应(ORR)电催化剂,然而CoFe_(2)O_(4)在HER中表现出电导率差、电催化反应慢的特性。CoFe_(2)O_(4)中氧空位(Ov)的形成可以有效调控催化剂表面的电子结构,有助于产生更多的缺陷和空位,从而提高OER的活性。随后,引入磷原子填充在空位中,制备的P-Ov-CoFe_(2)O_(4)/IF在碱性电催化测试中展现出优异的HER和OER性能,在10 mA·cm^(-2)电流密度下HER和OER过电位仅为54和191 mV,Tafel斜率分别为57和54 mV·dec^(-1),并具有良好的循环稳定性。

Oxygen vacancies and hetero atom filling play an important role in the catalytic performance of materials.To develop an efficient and stable water electrolysis catalyst,based on the oxygen vacancies and phosphorus doping,nanoflower structures with oxygen vacancy and phosphorus doping were synthesized on iron foam by in-situ immersion growth and two-step heat treatment as hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)electrocatalysts.CoFe_(2)O_(4)has been reported as a promising electrocatalyst for OER and oxygen reduction reaction(ORR).However,CoFe_(2)O_(4)exhibits poor conductivity and slow electrocatalytic reaction in HER.The formation of oxygen vacancy(Ov)in CoFe_(2)O_(4)can effectively regulate the electronic structure of the catalyst surface and contribute to the formation of more defects and vacancies,thus improving the activity of OER.Then,we added phosphorus atoms to fill the vacancy,and the prepared P-Ov-CoFe_(2)O_(4)/IF showed excellent performance of HER and OER in the alkaline electrocatalytic test.At the current density of 10 mA·cm^(-2),the overpotentials of HER and OER were only 54 and 191 mV,and the Tafel slopes were 57 and 54 mV·dec^(-1),respectively.The prepared electrocatalyst also demonstrated excellent cycling stability.