高效且酸稳定的铱钴氧化物电催化析氧催化剂  

Efficient and acid stable iridium cobalt oxide oxygen evolution catalyst

作　　者：孙艺萌 刘琳[1,2] 韩洪宪 SUN Yimeng;LIU Lin;HAN Hongxian(Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大连化学物理研究所,辽宁大连116023 [2]中国科学院大学,北京100049

出　　处：《工业催化》2025年第2期34-42,共9页Industrial Catalysis

基　　金：国家重点研发计划项目(2017YFA0204804);国家自然科学基金项目(21761142018);国家自然科学基金项目人工光合作用基础研究中心(22088102);大连市高层次人才创新工程项目(2019RD18)。

摘　　要：高效、酸稳定的析氧反应(OER)催化剂是规模化利用质子交换膜(PEM)电解水技术耦合可再生能源制取绿色氢能的关键。本论文通过简单的一步熔盐热分解法制备了一系列不同铱含量的铱钴氧化物催化剂并进行了优化。电化学测试表明,相比于氧化钴的迅速失活,最优铱负载量的Ir_(0.13)Co_(0.87)O_(x)催化剂在50 mA·cm^(-2)电流密度下的过电位仅为270 mV,同时在100 mA·cm^(-2)的高电流密度下能稳定运行50 h以上。构效关系研究表明,铱均匀掺杂在氧化钴的体相晶格提高了催化剂的稳定性并大大降低了电荷传输的阻抗,同时Ir以平均价态略高于+4取代了Co_(3)O_(4)中部分四面体配位的Co^(2+),使得催化剂表面主要由稳定的高价Ir^(4+)和Co^(3+)存在,从而大大提高了催化剂的活性和稳定性。本工作揭示了铱掺杂过渡金属氧化物的配位结构和价态对催化剂的OER活性和稳定性起到关键性作用,这为进一步发展酸性介质中高效、稳定、经济的低铱OER电催化剂提供了新的思路。Efficient and acid stable oxygen evolution reaction(OER)catalysts are crucial for the large-scale application of proton exchange membrane(PEM)electrolysis technology coupled with renewable energy to produce green hydrogen.In this work,a series of iridium cobalt oxide catalysts with different iridium contents are prepared through a simple one-step molten salt thermal decomposition method followd by optimization.Electrochemical tests have shown that,compared with the rapid deactivation of cobalt oxide,the optimzied Ir 0.13 Co 0.87 O_(x)catalyst has an overpotential of only 270 mV at a current density of 50 mA·cm^(-2),and can stably work for more than 50 h at a high current density of 100 mA·cm^(-2).The study of structure-activity relationship shows that the uniform doping of iridium in the bulk lattice of cobalt oxide improves the stability of the catalyst and greatly reduces the impedance of charge transfer.At the same time,Ir replaces some of the tetrahedral coordinated Co^(2+)in Co 3 O 4 with an average valence state slightly higher than+4,resulting in the catalyst surface prevails stable and high valence Ir^(4+)and Co^(3+)both in tetrahedral and octahedral form,hence greatly improving the activity and stability of the catalyst.This work reveals that the coordination structure and valence state of Ir in doped transition metal oxides play a crucial role in improving the OER activity and stability,hence provides a new solution for the development of efficient and stable low iridium based OER electrocatalysts working in acidic media.

关 键 词：催化化学 低铱催化剂 铱负载氧化钴 酸稳定析氧催化剂 质子交换膜电解水 

分 类 号：O643.36[理学—物理化学] TQ035[理学—化学]