高价金属钽掺杂无定型氧化铱用于酸性氧析出反应  

High‐valence metal‐doped amorphous IrOx as active and stable electrocatalyst for acidic oxygen evolution reaction

作　　者：张宁[1,2] 杜家毅[1,2] 周纳 王德鹏 鲍迪 钟海霞[1,2] 张新波[1,2] Ning Zhang;Jiayi Du;Na Zhou;Depeng Wang;Di Bao;Haixia Zhong;Xinbo Zhang(State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Science,Changchun 130022,Jilin,China;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026,Anhui,China)

机构地区：[1]中国科学院长春应用化学研究所,稀土资源利用国家重点实验室,吉林长春130022 [2]中国科学技术大学应用化学与工程学院,安徽合肥230026

出　　处：《Chinese Journal of Catalysis》2023年第10期134-142,共9页催化学报（英文）

基　　金：国家重点研发计划(2020YFE0204500);国家自然科学基金优秀青年科学基金项目(海外),国家自然科学基金(52071311,52273277,52072362,21905269);吉林省科技发展计划资助项目(20220201112GX);中国科学院青年创新促进会(2021223).

摘　　要：氢能作为一种潜在的能源载体,有望取代化石燃料,解决当今社会的能源需求和环境问题.质子交换膜电解水(PEMWE)技术因其工作电流密度大、氢气纯度高和系统响应迅速等优点,能够有效地弥补可再生能源波动性等缺点,被认为是一种利用可再生能源制氢的可持续手段.但其阳极氧析出反应(OER)为四电子/质子转移过程,反应动力学缓慢,同时强氧化性和强酸性环境会对阳极催化剂的产生腐蚀,导致稳定性差,因此亟需开发高效且稳定的催化剂.研究发现,无定型氧化铱材料中的特殊缺陷结构可显著提升其催化酸性OER的活性,但该结构也会加速反应过程中铱的溶解,导致催化剂稳定性降低,严重限制了其实际应用.本文采用高价金属掺杂的策略,利用高价金属元素与氧的强成键作用,对无定型氧化铱的整体结构及活性位点起到优化且稳定的作用.首先,采用改性的亚当斯熔融法制备了金属钽掺杂的无定型氧化铱:350-Ta@IrO_(x),400-Ta@IrO_(x),450-Ta@IrO_(x)(350,400和450代表样品分别在350,400和450℃烧结),并用于催化酸性OER;作为对比,制备了无掺杂的无定型氧化铱:350-IrO_(x),400-IrO_(x)和450-IrO_(x).然后,通过扫描电子显微镜、透射电子显微镜(TEM)和X射线衍射等表征技术考察了材料的宏观形貌及微观结构.结果表明,掺杂后的350-Ta@IrO_(x)材料表面具有丰富的氧空位贡献的活性位点,且表现出多晶的超小纳米颗粒形貌.电化学测试结果表明,350-Ta@IrO_(x)具有较好的酸性OER活性,在10 mA cm-2的电流密度下,过电势仅为223 mV,在1.55 V vs.RHE的电位下质量活性为1207.4 A gIr-1,是商业二氧化铱的147.7倍.且该催化剂的稳定性比未掺杂Ta样品及商业二氧化铱有明显提升,在0.5 mol L^(-1)硫酸溶液中反应500 h后电位未发生明显变化.密度泛函理论计算结果表明,Ta掺杂与构建缺陷有利于OER决速步中水分子的亲核进攻,从而提升催�Proton-exchange membrane water electrolysis,particularly driven by renewable electricity,is a sustainable strategy for green hydrogen production.However,developing highly active and stable electrocatalysts to accelerate the oxygen evolution reaction(OER)remains challenging.Herein,we introduce an effective strategy for constructing high-valence metal-doped IrO_(x)with abundant oxygen vacancies,while simultaneously enhancing the catalytic activity and stability of the acidic OER.The synthesized Ta-doped IrO_(x)(350-Ta@IrO_(x))exhibits ultramicroscopic nanoparticle morphology and abundant surface oxygen vacancies,enabling a rapid OER process with a low overpotential of 223 mV at 10 mA cm^(-2)and 147.7 times higher mass activity(1207.4 A gIr–1)than that of commercial IrO_(2) at 1.55 V versus the reversible hydrogen electrode.More importantly,350-Ta@IrO_(x)affords excellent stability with insignificant potential degradation after 500 h of electrolysis at 10 mA cm^(–2),originating from the low operating potential and suppressed dissolution and oxidation of oxygen vacancy active sites via Ta doping.Density functional theory calculations suggest that Ta doping and oxygen defect engineering are effective in facilitating the nucleophilic attack of water molecules,thereby accelerating the rate-determining step toward high catalytic OER activity on Ta-doped IrO_(x).We anticipate that this study will provide an effective method to obtain active and stable electrocatalysts via high-valence metal doping.

关 键 词：酸性析氧反应 高价金属掺杂 氧化铱 氧缺陷 电催化 

分 类 号：O64[理学—物理化学]