铁系氧化物电极材料的多尺度调控及其大电流密度析氧催化性能

Iron-based oxides have been emerged as oxygen evolving reaction (OER) catalysts for water electrolysis due to their eco-friendly, inexpensive, and excellent chemical stability. However, their practical applications are suffered from the high overpotential to realize large current density during water splitting. In this proposal, we plan to synthesize self-supported MOx (M for NiFe, CoFe, NiCo, etc.) electrodes with novel structure and composition for water oxidation through aqueous solution deposition method. Electronic structure regulation at atomic-scale, fabricating hierarchical morphology at nano/micro-scale and optimized the interface characterization in gas−solid−liquid boundary at macro-scale are expected to increase the oxygen evolving active sites and promote the charge transfer ability as well as enhance hydrophilicity, thus realizing high efficient OER performance at lower overpotential and larger current density. The physical and chemical experimental measurements, united with theoretical evaluation will be applied to investigate the effects of composition, structure and surface/interfacial phenomenon on the water oxidation catalytic activity. We will also elucidate the coupling mechanism on improving the OER performances among electron coupling and synergistic effect mechanism of multi-scale and the electrocatalytic oxygen evolving mechanism, so as to obtain the basic principles for preparation and modification of iron-based metal oxides nanostructures with excellent OER activity, finally providing experimental guidance and theoretical basis for the development and application in engineering.

铁系金属氧化物作为电解水析氧催化材料，具有环境友好、廉价易得等优点，但实现其大电流密度析氧能耗高，有碍其应用。因此，研发具有低过电位、大电流密度的电极材料是解决这一难题的关键。本项目拟采用液相原位制备技术构筑新型铁系双金属氧化物MOx析氧自支撑电极（M为铁系双金属NiFe，CoFe或NiCo等），基于原子尺寸的离子掺杂，微纳米尺度的多级形貌构筑以及宏观尺度气-固-液三相界面优化等多尺度综合调控，提高其析氧活性位，增强其电荷传递并调控电极表面浸润性和气泡逸出速率，进而实现低过电位、大电流密度的析氧催化性能。通过现代物理、化学表征手段，结合理论计算研究其组成、晶相及表/界面结构与析氧催化性能的关系，重点解析材料的表面电子调控机制、多尺度协同机制及三相界面优化材料析氧性能的原理与材料的电催化机理。从而获得高活性铁系析氧电极材料的性能优化机理及可控制备技术，为其工程应用提供理论支撑和技术依据。

铁系金属氧化物作为电解水析氧催化材料，具有环境友好、廉价易得等优点，但实现其大电流密度析氧能耗高，有碍其应用。因此，研发具有低过电位、大电流密度的电极材料是解决这一难题的关键。本项目围绕如何实现铁系氧化物电极材料的多尺度调控及其大电流密度析氧催化性能，1）提出电化学沉积、化学镀等方法对NiFe基析氧催化剂表面进行金属氧酸盐改性的策略，在NiFe2O4，α-Fe2O3等电极表面修饰金属磷酸盐、硼酸盐并实现其优异的析氧性能；2）将纳米结构异质结构引入NiFe基析氧催化剂中，提出基于催化剂不同组分之间的界面效应对反应中间体在电催化剂表面的化学吸附具有较强的调制能力，为廉价、高效的大电流碱性电解水析氧催化材料的研发提供了新的研究思路；3）提出B，P，S离子调控NiFe催化剂表面特性实现高效大电流析氧性能的策略及其调控大电流析氧催化反应机制，揭示了B，P，S等阴离子调控NiFe催化剂析氧催化性能的机理；4）采用阳离子刻蚀，阴离子刻蚀等原位电化学深度刻蚀NiFe基析氧催化材料，提出在电化学氧化过程中实现“原位刻蚀-浸出-表面自重构”的策略，阐明阳离子或阴离子的原位刻蚀诱导活性相生成机理，实现活性相高本征活性的四价Ni物种的稳定存在，激发晶格氧机制，揭示了电化学重构活性相对材料性能强化的影响规律。在项目执行期内，在国内外主流学术期刊已发表研究论文21篇，参与撰写学术专著1章节，申请中国发明专利1项，参加国际或国内学术会议专题报告/墙报展示11人次，以第一完成人获得2021年度山西省自然科学二等奖1项，培养硕士毕业生9名，培养项目相关在读硕士1名，在读博士2名。该项目的成功实施，为廉价、高效、长寿命的电解水制氢催化剂的研发提供重要的理论基础和技术依据。