富氧空位铁基复合材料的制备及其电催化析氢性能

Preparation and electrocatalytic hydrogen evolution performance of iron-based composites with rich oxygen vacancies

电解水制氢绿色无污染,或将成为日益紧张的能源问题与碳中和战略的重要突破方向。目前,贵金属稀缺,以Pt/C为代表的贵金属析氢(HER)催化剂不适宜长久使用。泡沫铁(IF)结构稳定、来源广泛,以IF作为基底,采取简单的浸泡方法在IF上原位生长针形片状的羟基氧化铁(FeOOH/IF),然后通过真空处理制备含有氧空位的四氧化三铁(Ov-Fe_(3)O_(4)/IF),进一步磷化掺杂,制备出氧空位和磷原子掺杂协同调控的四氧化三铁(P-Ov-Fe_(3)O_(4)/IF)纳米针。磷原子的掺杂可以优化铁原子周围电子环境,激活Fe_(3)O_(4)的催化活性;氧空位可以增强材料的导电性,并提供缺陷,更有助于磷原子的掺杂。结果表明:P-Ov-Fe_(3)O_(4)/IF析氢性能优异,在-10 mA·cm^(-2)时,过电位仅40.96 mV,塔菲尔斜率为70.93 mV·dec^(-1),表现出类Pt/C性能,并且在不同电流下连续运作96 h后,电压变化基本忽略不计,稳定性优异。氧空位和磷原子掺杂可共同促进铁基材料的电催化析氢性能,本文为非贵金属电催化材料的制备提供了新的思路和策略。

Hydrogen generation by water electrolysis is an environmentally sound approach,it may become a significant breakthrough direction for the increasingly tense energy problems and carbon neutrality strategy.At present,precious metals are scarce,and precious metal hydrogen evolution(HER)catalysts represented by Pt/C are not suitable for long-term use.Iron foam(IF)is stable in structure and widely available.Based on IF,the simple soaking method was adopted to grow needle-shaped flaky ferric hydroxide(FeOOH/IF)on IF in situ,and then ferroferric oxide(Ov-Fe_(3)O_(4)/IF)containing oxygen vacancies(Ovs)was prepared by vacuum treatment,finally,phosphorization was carried out to prepare the Fe_(3)O_(4) nanoneedle which was coordinated and controlled by Ovs and P atom doping(P-Ov-Fe_(3)O_(4)/IF).The doping of P atom can optimize the electronic environment around Fe atom and activate the catalytic activity of Fe_(3)O_(4);Ovs can enhance the conductivity of the material and provide defects,which are more conducive to doping of P atoms.The results show that P-Ov-Fe_(3)O_(4)/IF has excellent HER performance.At−10 mA·cm^(−2),the overpotential is only 40.96 mV,and the Tafel slope is 70.93 mV·dec^(−1),which is similar to that of Pt/C.And after 96 hours of continuous operation under different currents,the voltage change is basically negligible and the stability is excellent.Ovs and P atom doping can jointly promote the electrocatalytic HER performance of iron-based materials.This study provides new ideas and strategies for the preparation of non-precious metal electrocatalytic materials.