Self-supporting NiFe LDH-MoS_(x) integrated electrode for highly efficient water splitting at the industrial electrolysis conditions  

自支撑NiFe LDH-MoS_(x)集成电极在工业电解水条件下实现高效电解水

作　　者：Han Zhang Guoqiang Shen Xinying Liu Bo Ning Chengxiang Shi Lun Pan 张晗;沈国强;刘鑫迎;宁博;史成香;潘伦;张香文;黄振峰;邹吉军(天津大学化工学院,绿色合成与转化教育部重点实验室,天津300072;天津化学化工协同创新中心,天津300072)

机构地区：[1]Key Laboratory for Green Chemical Technology of the Ministry of Education,School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China [2]Collaborative Innovative Center of Chemical Science and Engineering(Tianjin),Tianjin 300072,China

出　　处：《Chinese Journal of Catalysis》2021年第10期1732-1741,共10页催化学报（英文）

基　　金：国家重点研发计划(2020YFA0710000);国家自然科学基金(22008170,21978200).

摘　　要：Developing effective and practical electrocatalyst under industrial electrolysis conditions is critical for renewable hydrogen production.Herein,we report the self-supporting NiFe LDH-MoS_(x) integrated electrode for water oxidation under normal alkaline test condition(1 M KOH at 25℃)and simulated industrial electrolysis conditions(5 M KOH at 65℃).Such optimized electrode exhibits excellent oxygen evolution reaction(OER)performance with overpotential of 195 and 290 mV at current density of 100 and 400 mA·cm^(-2) under normal alkaline test condition.Notably,only over-potential of 156 and 201 mV were required to achieve the current density of 100 and 400mA·cm^(-2) under simulated industrial electrolysis conditions.No significant degradations were observed after long-term durability tests for both conditions.When using in two-electrode system,the operational voltages of 1.44 and 1.72 V were required to achieve a current density of 10 and 100 mA·cm^(-2) for the overall water splitting test(NiFe LDH-MoS_(x)/INF||20%Pt/C).Additionally,the operational voltage of employing NiFe LDH-MoS_(x)/INF as both cathode and anode merely require 1.52 V at 50mA·cm^(-2) at simulated industrial electrolysis conditions.Notably,a membrane electrode assembly(MEA)for anion exchange membrane water electrolysis(AEMWEs)using NiFe LDH-MoS_(x)/INF as an anode catalyst exhibited an energy conversion efficiency of 71.8%at current density of 400 mA·cm^(-2)in 1 M KOH at 60℃.Further experimental results reveal that sulfurized substrate not only improved the conductivity of NiFe LDH,but also regulated its electronic configurations and atomic composition,leading to the excellent activity.The easy-obtained and cost-effective integrated electrodes are expected to meet the large-scale application of industrial water electrolysis.化石燃料的枯竭和不断增长的能源需求给人类带来巨大的挑战,加之能源消耗过程带来的环境问题使得开发清洁可再生绿色能源迫在眉睫.氢能具有零排放、可再生、能量高和来源广等特点,且可通过化石能源和电解水制取,是未来人类最理想的替代能源之一.相较于化石能源制氢,电解水制氢被认为是一种最有前途的清洁制氢技术,能够将可再生能源(例如太阳能和风能)产生的剩余电能以化学能的形式存储起来.电解水反应由发生在阴极的析氢反应与发生在阳极的析氧反应组成.其中,析氧反应涉及多个质子和电子转移,反应动力学缓慢严重限制了其水分解的整体效率.为满足实际应用,亟待开发低成本、高催化活性和在工业电解条件(60-80℃,20%-30%KOH,400mA·cm^(-2))下长期稳定性强等特性的析氧催化剂.本文报道了一种用于析氧反应的自支撑泡沫镰铁自支撑的镰铁层状双金属氢氧化物-二硫化钼(NiFe LDH-MoS_(x)/INF)集成电极,在正常碱性测试条件(25℃,1 M KOH)和模拟工业电解条件(65℃,5 M KOH)下均表现出优异的催化性能.优化后的电极在一般碱性测试条件下,过电势仅需195和290 mV即可达到100和400mA·cm^(-2)的电流密度.在模拟工业电解条件下达到相同的电流密度,过电势只需156和201mV.在两种条件下进行长期稳定性测试,催化剂均未观察到明显的失活现象.在两电极体系(NiFe LDH-MoS.yiNF||20%Pt/C)全解水测试中,达到100mA·cm^(-2)电流密度仅需1.72 V的电压.还使用NiFe LDH-MoS.v/INF作为阳极催化剂构建膜电极并评价其阴离子交换膜电解水的性能:在400mA·cm^(-2)的电流密度下能量转换效率(60℃,1 M KOH)为71.8%.综上,原位生长策略保证了此类电极的长期稳定性.硫化基底的存在可以控制NiFe LDH的生长厚度,从而提高集成电极的整体导电性.另外,MoS_(x)的引入进一步调节了NiFe LDH的电子结构,进而优化了反应�

关 键 词：Self-supporting integrated electrode NiFe LDH Electronic structure modulation Industrial alkaline water electrolysis Membrane-electrode assembly 

分 类 号：TQ116.2[化学工程—无机化工]