Sun Ke, Liang Xiao, Wang Xiyang, Wu Yimin A, Jana Subhajit, Zou Yongcun, Zhao Xiao, Chen Hui, Zou Xiaoxin
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China.
Department of Mechanical and Mechatronics Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Angew Chem Int Ed Engl. 2025 May;64(21):e202504531. doi: 10.1002/anie.202504531. Epub 2025 Mar 23.
Reducing iridium packing density (g cm electrode) represents a critical pathway to lower geometric Ir loading in proton exchange membrane water electrolyzers (PEMWEs), yet conventional approaches often cause performance issues of anode catalyst layer due to decreased structural stability and limited electron/mass transport efficiency. Here, we present deformable hollow IrO nanospheres (dh-IrO) as a structural-engineered catalyst architecture that achieves an ultralow Ir packing density (20% of conventional IrO nanoparticle-based electrodes) while maintaining high catalytic activity and durability at reduced Ir loadings. Scalable synthesis of dh-IrO via a hard-template method-featuring precise SiO nanosphere templating and conformal Ir(OH) coating-enables batch production of tens of grams. Through cavity dimension and shell thickness optimization, dh-IrO demonstrates excellent mechanical resilience to necessary electrode fabrication stresses, including high-shear agitation, ultrasonic processing and hot-pressing. In the anode catalyst layer, the quasi-ordered close packing of dh-IrO nanospheres simultaneously maximizes electrochemically active surface area, suppresses particle migration and agglomeration, and establishes percolated electron highways and rapid mass transport channels. The architected anode delivers high PEMWE performance (e.g., 1 A cm @1.60 V and 2 A cm @1.75 V@80 °C), while demonstrating excellent operational durability with <1.5% voltage loss over 3000 h.
降低铱的堆积密度（克/平方厘米电极）是降低质子交换膜水电解槽（PEMWEs）中几何铱负载量的关键途径，然而传统方法由于结构稳定性降低和电子/质量传输效率受限，常常会导致阳极催化剂层出现性能问题。在此，我们展示了可变形的空心氧化铱纳米球（dh-IrO），这是一种经过结构设计的催化剂结构，在降低铱负载量的情况下，能实现超低的铱堆积密度（仅为传统基于氧化铱纳米颗粒电极的20%），同时保持高催化活性和耐久性。通过硬模板法可扩展合成dh-IrO，其特点是精确的二氧化硅纳米球模板化和共形氢氧化铱涂层，能够批量生产数十克产品。通过优化空腔尺寸和壳层厚度，dh-IrO对必要的电极制造应力，包括高剪切搅拌、超声处理和热压，表现出优异的机械弹性。在阳极催化剂层中，dh-IrO纳米球的准有序紧密堆积同时最大化了电化学活性表面积，抑制了颗粒迁移和团聚，并建立了渗透的电子通道和快速的质量传输通道。这种设计的阳极在质子交换膜水电解槽中表现出高性能（例如，在80°C时，1.60 V下达到1 A/cm²，1.75 V下达到2 A/cm²），同时在3000小时内表现出优异的运行耐久性，电压损失小于1.5%。
