引用本文
王志达, 卢卓信, 史言, 郭常青, 谭弘毅, 申丽莎, 涂志明, 闫常峰. 高电流密度PEM水电解OER催化材料研究现状与分析[J]. 新能源进展, 2024,12(2): 133-140.
WANG Zhida, LU Zhuoxin, SHI Yan, GUO Changqing, TAN Hongyi, SHEN Lisha, TU Zhiming, YAN Changfeng. Development and Analysis on Structural Design of OER Catalyst for PEM Water Electrolysis Under High Current Density[J]. ADVANCES IN NEW AND RENEWABLE ENERGY , 2024,12(2): 133-140.  
Doi: 10.3969/j.issn.2095-560X.2024.02.003
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高电流密度PEM水电解OER催化材料研究现状与分析
王志达1,2,3,†, 卢卓信1,2,3, 史言1,2,3, 郭常青1,2,3, 谭弘毅1,2,3, 申丽莎1,2,3, 涂志明1,2,3, 闫常峰1,2,3,†
1.中国科学院广州能源研究所,广州 510640
2.中国科学院可再生能源重点实验室,广州 510640
3.广东省新能源和可再生能源研究开发与应用重点实验室,广州 510640
† 通信作者：王志达,E-mail：wangzd@ms.giec.ac.cn;闫常峰,E-mail：yancf@ms.giec.ac.cn

作者简介：王志达（1979-）男,博士,副研究员,主要从事燃料电池、水电解相关催化材料和电催化机理等研究。闫常峰（1969-）男,博士,研究员,主要从事氢能制取和应用以及相关器件、装置、系统的开发等研究。

收稿日期: 2023-08-16 修订日期：2023-09-26
基金项目: 中国科学院科技服务网络计划（STS计划）项目（KFJ-STS-QYZD-2021-02-003）; 广州市科技计划项目（202103040002）; 广州市科技计划项目（202206050003）; 芜湖市核心技术攻关项目（2022hg01）
摘要

因强酸性、高过电位以及强氧化环境等问题,商业化质子交换膜（PEM）水电解析氧（OER）阳极需采用高载量的贵金属材料,且目前尚无替代的非贵金属催化剂,导致成本居高不下。以高电流密度（HCD）提升功率密度是PEM水电解未来发展趋势,但随着电流密度升高,水电解反应过电位也近似线性增长,需要催化材料更高的电导率和更快的物质运输,以降低电流和电解效率的损失。因此,开发高性能OER催化剂对推动PEM水电解制氢产业的发展意义重大。介绍了PEM水电解与可再生能源的契合性,从OER四电子反应机理出发,揭示OER催化剂研究意义;结合已有的研究报道,从形貌尺寸、表面结构、传电能力、电化学反应微环境等四方面,分析了高电流密度下OER催化材料的研究现状及其提高PEM水电解传输效率的原因;对高电流密度PEM水电解OER催化材料未来的发展趋势提出建议并进行了展望。

关键词: 质子交换膜; 高电流密度; 析氧反应; 阳极催化材料; 结构设计
中图分类号:TK91 文献标识码:A 文章编号:2095-560X（2024）02-0133-08
Development and Analysis on Structural Design of OER Catalyst for PEM Water Electrolysis Under High Current Density
WANG Zhida1,2,3,†, LU Zhuoxin1,2,3, SHI Yan1,2,3, GUO Changqing1,2,3, TAN Hongyi1,2,3, SHEN Lisha1,2,3, TU Zhiming1,2,3, YAN Changfeng1,2,3,†
1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
2. CAS Key Laboratory of Renewable Energy, Guangzhou 510640, China
3. Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China
Abstract

Due to the acidic, high overpotential, and oxidizing environment, the commercial proton exchange membrane (PEM) water electrolysis usually requires very high loading of platinum group metals (PGMs) for the oxygen reduction reaction (OER) on the anode, without PGM-free metal catalysts available at present and leading to high costs. Alternatively, using high current density (HCD) to increase the power density is a feasible way to reduce the cost of PEM water electrolysis. However, with the current density increase, the water electrolysis overpotential also increases in an approximate linearship, which presents a big challenge for the charge and mass transfer. Therefore, the development of catalysts with high OER activity plays an important role in improving the efficiency of the PEM water electrolysis. This review introduced the compatibility of PEM water electrolysis with the renewable energy sources, and the fundamentals of OER catalyst development on the point view of the 4-e OER mechanism was revealed. Then the recent development of the OER catalysts was summarized from four aspects, including morphologies, surface structures, in-plane transfer capacity, and electrochemical reaction environment, and the reasons of their enhancement on transfer efficiency were analyzed. Finally, suggestions and insights on the trends of OER catalytic materials for PEM water electrolysis at high current densities were provided.

Key words: proton exchange membrane; high current density; oxygen evolution reaction; anode catalytic material; structure design
0 引言

在“ 双碳” 目标下, 我国的能源结构和体系继续向清洁化、低碳化、安全化深度转型, 发展光伏、风能等可再生能源取代传统化石燃料是我国能源体系转型的必经之路。但太阳能、风能等可再生能源受天气影响大, 波动性强, 不能产生稳定的电流供应, 而目前电网只能容纳约15%的非稳定电源[1, 2]; 此外, 峰谷电也急需可行的能源存储介质来避免能量的浪费。以水电解方式制氢作为消纳的储能装置, 可实现绿色能源大规模、跨季节的高效利用和峰谷电的高效存储[3, 4, 5, 6, 7]。据中国氢能产业联盟和氢能研究院测算, 2030年, 我国氢气需求量将为3 700 ~ 4 000万吨, 其中水电解绿氢供给约为770万吨, 占比接近20%, 市场规模预测将达1 100亿元。

目前的水电解制氢主要包括碱性槽（alkaline, ALK）、阴离子交换膜（anion exchange membrane, AEM）、固体氧化物电解水（solid oxide electrolysis, SOE）和质子交换膜（proton exchange membrane, PEM）四种技术[8]。ALK制氢规模大、技术相对成熟, 但制氢效率和电流密度相对比较低; AEM可以采用Fe、Co等非贵金属催化剂, 成本低、材料耐腐蚀, 目前仍处于研究起步阶段; SOE能量转换率高, 缺点是运行温度高、耐久性差[9, 10, 11]。与前三种技术相比, PEM水电解具有效率高、响应快、氢气纯度高等优势, 完全耦合可再生能源的波动性特点, 是目前重点发展的水电解制氢技术[12]。

1 OER催化材料研究意义

PEM水电解主要分为两个半反应, 分别是阴极的析氢反应（hydrogen evolution reaction, HER）和阳极的析氧反应（oxygen evolution reaction, OER）[13]。相对于HER的双电子反应, OER则涉及四个电子的传递[14]：

${{\text{H}}_{\text{2}}}\text{O}+\mathop{{}}^{* }\to {{\text{H}}^{+}}+{}^{* }\text{OH}+{{\text{e}}^{-}}$ (1)

${}^{* }\text{OH}\to {{\text{H}}^{+}}+{}^{* }\text{O}+{{\text{e}}^{-}}$ (2)

${}^{* }\text{O}+{{\text{H}}_{\text{2}}}\text{O}\to {{\text{H}}^{+}}+{}^{* }\text{OOH}{{+}^{{}}}{{\text{e}}^{-}}$ (3)

${}^{* }\text{OOH}\to {{\text{H}}^{+}}+{{\text{O}}_{\text{2}}}{{\text{+}}^{{}}}{{\text{e}}^{-}}$ (4)

由以上四电子反应机制可知, OER反应过程需要连续的中间价态变化, 包括O-H键的断裂和O-O键的形成等步骤, 反应过程复杂, 需要高电势来克服连续的能量势垒[15]。因此, 阳极OER是PEM水电解的主要瓶颈所在, 高性能OER催化材料的开发对推动PEM水电解制氢产业的发展意义重大[16]。

强酸性、电极反应过电位高以及阳极强氧化环境造成的腐蚀问题, 导致目前商业化PEM水电解均需采用高载量的贵金属Ir基、Ru基催化剂[17, 18, 19]。尽管廉价过渡金属催化剂体系已多有研究, 但基本还停留在实验室研究阶段, 电解效率或是寿命难以满足当前商业化PEM水电解装置的要求[5, 20, 21], 特别是阳极, 目前尚无替代的非贵金属催化剂[22, 23, 24, 25]。为降低PEM水电解成本, 采用高电流密度（high current density, HCD）提升功率密度是当前的主要思路[26, 27], 国际上主流制造商已逐步将额定工况的电流密度从1 A/cm2提升至2 ~ 3 A/cm2, 如欧洲燃料电池与氢能联合企业组织（the Fuel Cells and Hydrogen Joint Undertaking, FCHJU）提出2030年达到2.5 A/cm2。但随着电流密度的升高, PEM水电解过电位也近似线性增长, 需要催化层更高的传电效率, 以降低电流和电解效率的损失; 同时高电流下水电解反应也会更为剧烈, 会更快地消耗反应物和生成产物, 容易发生气泡积累导致活性位点覆盖, 因此需要更快速的物质传输[28]。由此可见, 高电流密度PEM水电解关键催化材料的开发与电荷及物质传输紧密相关, 明晰三相反应界面与质电传输机制, 开发高OER活性催化剂, 构筑高传输效率催化层, 是高电流密度下提高水电解效率的关键途径。

2 OER催化材料研究现状与分析
2.1 尺寸形貌

通过调整催化剂颗粒的尺寸大小和形貌, 可以制备具有较高比表面积和独特化物特性的低维度纳米材料, 在特定方向上设计较短的电荷传递和物质传输路径。目前的研究包括零维单原子和纳米颗粒[10, 29, 30], 一维纳米管线和二维纳米片层等[31, 32, 33, 34]。由于自身尺寸效应, 低维度材料还有自身独特的性质, 可进一步提升OER催化效率。如单原子催化剂具有最高的原子效率和质量活性, 可以与载体形成化学键作为活性位点, 提高催化剂的稳定性和催化活性[35]; 一维催化剂如碳纳米管等具有弯曲的表面, 结合管道的受限效应, 可以提高水电解反应的选择性[32]; 二维材料如金属有机框架纳米片等具有精确的结构, 其原子水平的厚度、丰富的活性位点和较大的表面积, 可以有效降低水电解过电位[36]。低维度催化剂活性位点的电子结构可以通过改变颗粒尺寸、形貌结构等本征特性进行有效设计, 进而优化电子传递, 提升高电流密度水电解效率。

低维催化剂表面存在大量的配位不饱和原子和不同的表面电子状态, 通过静电作用、范德华力、氢键等影响其与反应物/生成物之间的相互作用, 改变反应物/生成物在催化剂表面的浓度, 进而改变局部电化学能垒和界面黏附力, 促进催化剂的传质过程[37]。LIU等[38]制备了不同曲率半径的纳米尖催化材料, 发现高曲率的针尖可以加强电荷的聚集, 增强局部电场和促进反应物传递, 在OER中表现出更低的过电位和本征催化活性。低维催化剂还可以有效减小气-液-固界面的接触线长度, 降低催化剂和气泡之间的界面附着力, 有效缓解大电流下产生的气泡积累, 在提高传质效率同时, 还能提高其传质过程相关的机械稳定性[39]。

低维度材料本身作为组装单元, 可以进一步形成高级结构, 增强传质和传电能力[40]。BAIK等[41]采用改良亚当斯（Adams）方法, 在SiO2模板协助下合成了具有可控孔径分布的RuO2催化剂, 比表面积高达240 ~ 270 m2/g。与使用传统的亚当斯方法制备的催化剂相比, 具有大孔隙（超过总孔隙体积的20%）的RuO2催化剂电化学活性面积（electrochemical active surface area, ECSA）增加50%。并且由于多孔结构的存在, 反应过程中的物质传输也得到了进一步加强, 从而表现出更高的OER活性和稳定性。低维催化剂的这些特性可能会通过改变电子传递和质量传递过程来影响其在高电流密度下的性能, 因此, 催化剂的维度工程已被用作改变OER性能的一种重要策略[42, 43, 44]。

2.2 表面结构

催化剂表面构成及具有界面作用的异质结构都会影响催化剂的表面化学属性, 借助成分组成、原子掺杂、空位缺陷、电化学钝化等技术, 可以改变中间产物和催化活性位点之间的结合强度, 进而改善高电流下水电解效率[45]。LIM等[46]将Ir与过渡金属合金化形成Ir-Ni双金属纳米颗粒, 当Ir含量很低时, 在Ni核上形成一层薄的主要Ir壳, 呈菱形十二面体形状; 随着Ir含量的增加, Ir更多地沉积在顶点上, 以暴露高密度的Ir位点增加催化活性位。KWON等[47]将Co掺杂到Cu@IrCu核壳纳米晶的IrCu壁上, 合成了晶面可控的铱基空心纳米笼, 在酸性OER中表现出良好的活性和耐久性。SUN等[48]制备了高OER活性的Cu0.3Ir0.7Oδ 型催化剂, 发现性能的提升来自CuO6八面体中的姜-泰勒（Jahn-Teller）效应的增加。同时由于IrO6八面体几何结构畸变引起的晶格中的氧缺陷, 使dz2轨道被部分占据, 从而降低了OER的过电位。

在酸性条件下, PEM水电解阳极的高氧化电位会将金属材料转化为氧化物, 可以作为钝化层保护金属核心。JOVANOVIČ 等[49]系统研究了电化学处理前后金属Ir纳米颗粒的电化学溶解, 由于Ir表面氧化和还原过程, Ir颗粒在低于OER电位的情况下开始溶解, 电化学预处理的纳米Ir表面形成无定形Ir2O3钝化层, 表现出比金属Ir更高的稳定性。CHEREVKO等[50]利用电感耦合等离子体质谱的扫描流动池研究了酸性条件下贵金属（Ru、Pd、Au、Ir、Pt和Rh）和热氧化RuO2及IrO2薄膜的活性和稳定性, 结果表明, OER活性以Ru > Ir ≈ RuO2> IrO2的顺序下降, 而溶解率以IrO2 ≪ RuO2< Ir ≪ Ru的顺序增加。

异质结构中不同的化学成分和晶体结构还会引起诸如拉伸和压缩的晶格应变, 电荷能够通过各组分间界面转移, 影响位点对中间体的吸附能, 进而提高催化材料的传质传电效率。MENG等[51]制备了不同原子IrOx层的核壳IrCo@IrOx纳米枝晶, 从原位扩展的同步辐射精细结构中发现, 随着原子层的生长, IrOx层中Ir-O键的压缩应变减小, 优化了HOO* 结合强度, 降低决速步能量势垒, 从而获得优异的OER性能。HAO等[52]报道了一种具有晶界扭转应力IrOx基纳米催化剂, 在高电流密度（1.5 A/cm2@1.9 V）稳定运行500 h, 显微结构分析、X射线吸收光谱和理论计算显示, 基于扭转应变的Ir-O键的晶界和掺杂诱导的配体效应之间的协同效应, 调整了氧中间产物的吸附能量, 从而提高了催化活性和物质传输效率。

2.3 提升传电能力

引入高导电性材料作为载体或设计孔隙结构可以降低电阻抗, 增加活性位点间的距离, 促进电子和物质在催化剂-载体或催化剂-催化剂界面间的转移能力。可用的高导电性材料包括碳、金属和一些金属化合物, 结合维度工程和表面工程技术以利用高导电性材料获得催化剂高内在活性, 可直接提高催化剂在高电流密度下水电解的性能[53]。ZHANG等[54]将低载量Ir（质量分数为5.91%）纳米颗粒沉积在三维石墨泡沫（Ir/GF）上, 得到了酸性条件OER催化剂Ir/GF, 并且由于Ir-N配位的存在, Ir/GF活性和稳定性都得到了明显增强。TACKETT等[55]制备了铁氮化物为核、Ir为壳的Ir/Fe4N框架结构, 其薄Ir壳提高了Ir原子的利用率, 经电化学预处理后, 金属Ir壳被氧化为IrO2相, 在酸性氧化电位下可以保护Fe4N核, OER质量活性和稳定性均有显著提高。BELE等[56]以电化学生长法制备了高比表面积氧化钛纳米管, 然后通过氮化和固定Ir纳米颗粒形成了导电优异的TiON-Ir催化电极, 结果表明, 金属-载体强相互作用（strong metal support interaction, SMSI）可防止Ir过度氧化, 且TiO2嵌入Ir纳米颗粒中, 提高了传电能力, 有效提升OER活性; TiO2在载体TiON表面的自钝化实现了催化材料的稳定性。

同时, 由于高导电性材料对催化剂颗粒的分散能力, 反应物和反应产物可以快速进入活性位点参与反应, 有利于反应物的快速输送和产物的及时释放, 使催化电极处于高效稳定状态[57]。LIU等[58]以热氮化方法制备了具有颗粒多孔表面结构和内部孔状缺陷的Ti-TiN层, 随后将IrOx负载于Ti-TiN载体上, 在催化界面上形成了更多分散的IrOx催化活性点, 不仅增加了电子传导性, 还增强了质量吸附和传输, 表现出显著的电催化活性和稳定性。ZENG等[59]通过脱合金和热解将IrO2纳米颗粒整合到纳米孔金（nanoporous gold, NPG）上, 形成三维互联纳米孔超薄膜结构NPG/IrO2复合材料, 在PEM水电解中表现出1.73 V@2 A/cm2的高效性能, 载体NPG的三维多孔结构提高了电化学活性表面积, 增强质量传递和促进电解过程中产生的氧的释放, 表现出良好的OER活性和高效传质能力。MIN等[60]采用多步骤合成方法制备了高性能的IrOx/W-TiO2催化剂, 在贵金属总载量小于0.2 mg/cm2的情况下, 取得了1.60 V@1 A/cm2的高催化活性（Nafion 212）, 远超过无支撑的IrOx和商业IrO2; 原位电化学测试显示, W-TiO2载体的引入可以提高IrOx催化剂层的导电性和气体传输, 不仅大幅度降低了贵金属的载量, 还提高了PEM水电解性能。

金属催化剂和其载体间的耦合效应可能会发生相互间电子转移, 从而改变金属-电载体间的界面电阻[61]。为减少电化学极化和传质极化, 将催化剂直接在金属或碳材料表面生长自支撑催化层/催化电极, 增强传电和传质能力[62]。JIMENÉ Z等[63]使用不同比例的Co:Ir在碳基底上溅射制备了Ir-Co催化剂, 其Ir负载量均为250 μ g/cm2, 然后去除Co形成自支撑的树枝状纳米多孔结构。结果表明, 高Co含量的Ir-Co经酸洗后可以形成更高比表面积的多孔结构, 且ECSA随比表面积增加, 由于配体效应和超高分散性, 60β ℃下性能最好的催化剂比商业IrOx超出了10倍。GODINEZ-SALOMÓ N等[64]合成了自支撑的Ir-NiO催化材料, 该材料纳米架构包含了一个相互连接的金属铱镍合金网络, IrOx和NiOx位于表面区域, 在高电位下维持了三维纳米结构, 并形成了约5 Å 厚度的氧化物/氢氧化物表面层。研究还发现, 较低的热还原温度可以在表面形成更高浓度的氢氧化物和氧化镍, IrO表面的Ni取代降低了OER反应中第二电子转移步骤中吸附的中间物的激活能, 从而表现出更高的OER活性。部分研究认为低贵金属载量下的电化学活性面积损失源于横向导电限制, 使得催化层不与集流体接触的部分区域无法参与到反应中[65, 66]。DOAN等[67]通过喷涂和热处理方法在钛多孔传输层表面沉积了一层IrO2/TiO2, 有效改善了界面接触性能, 降低了金属-载体间界面电阻。YANG等[68]在PEM膜上预涂敷一层连续金纳米层, 为超低载量Ir（0.1 mg/cm2）催化层构筑横向电子/质子传输通道, 使质子在德拜长度（Debye length）内通过直线介孔传输, 大大提高了电极电导率; 并且, 介孔金纳米层将反应点从一维增加到二维, 从而使质量活性提高18倍, 1 A/cm2下电压较常规催化剂涂覆膜（catalyst-coated membrane, CCM）下降200 mV。

2.4 局部电化学微环境

电化学界面的局部电化学微环境与电流密度密切相关, 通过调节催化剂和反应物之间的相互作用, 可以实现高电流密度下水电解效率的提升[69]。酸性条件下, 阳极OER催化剂和反应水在亥姆霍兹（Helmholtz）层的相互作用不仅改变中间物和催化剂的结合强度, 局部微环境也可能使质子浓度发生变化, 而pH的改变进一步反作用于局部电化学微环境, 使OER反应速率发生改变[70]。FORNACIARI等[71]将实验、密度泛函理论（density functional theory, DFT）计算、微观动力学和传输模型结合, 系统探讨了整个pH范围下的OER性能。扰动分析和表面覆盖率表明, 局部环境质子传输在高电流密度OER动力学中起着关键作用。低电流密度下, 中性环境OER反应表现良好; 在更高的电流密度下, 酸性环境下OER表现更佳。借助多尺度模型分析发现, 这种转换是由于双重反应机制到单一速率决定步骤的变化。NONG等[72]采用脉冲伏安法和动态现场原位X射线吸收光谱研究了IrO2水电解反应, 发现施加的偏压并不直接作用于反应进程, 而是通过催化剂中的电荷积累影响电催化的电流, 活化自由能随着氧化电荷储存量的增加而线性下降; 空隙覆盖率随着过电位而改变, 并且与参与阳极反应的IrO2催化剂的去质子化相关联。LEE等[73]研究了碳载IrNi合金纳米颗粒（IrNi/C）的OER活性, 通过动态现场原位X射线吸收光谱和原位透射电子显微镜技术分析了IrNi/C在不同pH环境下的电子结构和原子排列, 发现金属元素在电催化反应过程中发生表面重构, 在中性pH条件下激活的IrNiOx/C显示出轻度氧化的薄IrOx壳, 在酸性和碱性电解质中分别显示出镍浸出的IrOx和富含镍的IrNiOx表面。因此, 通过研究局部微环境pH的变化, 优化催化剂与局部微环境物质间的相互作用, 可应用高活性OER催化剂的设计。

此外, 与催化剂化学结合或与催化剂形成复合/异质结构的配体也会影响中间产物的稳定性和反应过程, 尽管这些配体可能不是催化活性位点, 但仍然会对包括而不限于反应物的稳定性或中间物与催化位点之间结合强度等产生影响[74]。REIER等[75]研究了Ti圆柱体上热制备的Ir-Ni混合氧化物薄膜, 发现随着初始Ni含量的增加, Ir-Ni氧化膜配体OH浓度增加, 说明Ni浸出对催化剂表面OH的形成起到重要作用; 同时, 随着OH的积累, Ir-Ni混合氧化膜的OER活性也随之升高, 说明活性表面OH配体对OER过程至关重要。值得关注的是, OH作为配体提高催化活性同样也可以发生在碱性OER环境中, ZHANG等[76]设计开发出一种新型IrMo金属间化合物, 通过表面Mo位点上稳定吸附的OH配体, 对催化剂表面化学环境和电子结构进行优化, 实现了优异的电化学性能。

3 结论与展望

PEM水电解契合可再生能源电力随机性、间歇性和波动性特点, 是发展氢能产业、实现绿色能源的重要途径。本文基于PEM水电解阳极关键催化材料, 从尺寸形貌、表面结构、传电能力、电化学反应微环境等四方面, 介绍了目前高电流密度下OER催化材料的研究进展。综合来看, 以上所述催化材料设计策略都有各自显著的优点, 但也存在自身的某些限制。例如, 低维催化剂可以暴露更多的活性位点, 但也可能会引入过多的催化剂-催化剂界面, 从而降低薄膜的电导率, 其过小尺寸也可能由于表面不饱和原子的数量而降低其稳定性; 催化剂表面吸附剂和配体的存在可以稳定中间物以产生更高的内在活性, 然而, 它们也可能覆盖一些催化活性位点, 使电化学表面积降低并产生界面阻力[28]。此外, 电化学界面的局部电化学环境受电流密度的影响很大, 对高电流密度下电化学界面的反应机理的研究仍然有限, 阻碍了在工业相关的条件下合理设计高性能OER电催化剂相关工作。针对当前所面临的挑战, 未来可以考虑从以下几个方向开展研究：

（1）催化剂结构的先进设计方法。由于催化剂结构的复杂性, 特别是合金类和载体型催化剂, 其复杂化学组分为OER活性调节提供了更多可能性, 但给传统实验试错方法带来了困难, 需要借助基于第一性原理的DFT高通量计算并结合先进的机器学习来设计和筛选合适的组分和结构。

（2）电化学原位表征技术。由于电化学反应界面和OER反应过程的复杂性, 催化剂表面受到局部环境和外加过电位的动态影响, 具有时空依赖性, 常规的电化学表征方法难以捕捉OER瞬时动态变化, 需要借助先进的原位电化学表征技术, 实时研究OER反应路径和电荷传输对电化学界面和过程的影响, 深入了解高电流密度下催化剂结构-性能间的构效关系。

（3）理解器件层面对PEM水电解协同增效作用。将催化剂结构设计与其在PEM水电解中的应用结合起来, 深入研究催化剂在催化层中传输通道构筑与PEM水电解电化学特性间关系, 解读催化层纵向与横向传输耦合作用在电化学三相反应界面构筑机理, 建立电化学反应动力学与传输过程相耦合的跨组件模型。

因此, 在实际的催化材料制备中, 需要综合以上所述各种策略, 全面考虑维度设计、表面化学和电荷横向传输路径, 深入了解催化剂反应界面间相互作用, 明晰三相反应界面与高效传输通道影响机制, 权衡各因素之间关系, 进行催化剂和催化层多尺度设计, 以达到OER性能和PEM水电解效率提升的目的。

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