3DIr4E: Three-Dimensional low Ir loading anodes For proton exchange membrane water Electrolyzers

质子交换膜(PEM)电解槽对可再生能源的储存和转化具有重要意义。然而，由于多个质子耦合电子转移步骤的参与，阳极上的析氧反应(OER)具有内在的迟缓动力学，这是阻碍质子交换膜电解槽实际应用的主要障碍之一。因此，高活性、高性价比和耐用的电催化剂对于降低OER的高动力学势垒以实现增强反应动力学，从而提高整体器件效率和降低施加电压是必不可少的。到目前为止，只有Ir(Ir)基材料具有足够的耐腐蚀性来满足PEM电解槽的苛刻酸性和氧化环境。遗憾的是，它们的高度稀缺性和相对较低的OER活性极大地阻碍了它们的工业大规模应用。因此，建立新的催化剂电极设计和优化策略，在保持高活性和高稳定性的同时最大限度地减少Ir的金属含量，对PEM电解槽具有重要的意义。在此，3DIr4PEMWE项目旨在开发一种基于一维IrO2纳米结构阵列的三维有序阳极设计，该阵列装饰有原子分散的Ru和Sr单原子催化剂(记为Ru-Sr掺杂IrO2)。这种独特的结构可以有效地克服基于超细颗粒催化剂的电极在运行过程中因催化剂利用率低而导致的活性损失，以及由于颗粒的溶解和聚集而导致的活性下降，从而同时提高了氧电极在运行过程中的质量活性、结构稳定性和机械强度。我们相信，欧盟资助的3DIr4PEMWE项目将加快PEM水电解槽技术的产业化，早日实现雄心勃勃的氢能社会

Proton exchange membrane (PEM) water electrolyzers hold great significance for renewable energy storage and conversion. However, the oxygen evolution reaction (OER) at the anode has intrinsically sluggish kinetics due to the involvement of multiple proton-coupled electron transfer steps, which is one of the main roadblocks that hinder the practical application of PEM water electrolyzers. Thus, highly active, cost-effective, and durable electrocatalysts are indispensable for lowering the high kinetic barrier of OER to achieve boosted reaction kinetics, so that to improve the overall device efficiency and decrease the applied voltage. To date, only Iridium (Ir) based materials possess adequate corrosion resistance to meet the harsh acidic and oxidative environment of the PEM electrolyzers. Unfortunately, their high degree of scarcity and relatively low OER activity greatly hinder their industrial mass applications. Therefore, the establishment of new strategies for catalyst electrode design and optimization to minimize the Ir metal content while preserving a high activity and stability of OER is of great significance for PEM electrolyzers. Herein, the 3DIr4PEMWE project aims to develop a 3D ordered anode design based on 1D IrO2 nanostructure arrays decorated with atomically dispersed Ru and Sr single atoms catalysts (denoted Ru-Sr doped IrO2). This unique architecture can effectively circumvent the drawbacks of the electrodes based on ultrafine particulate catalysts, including the activity loss due to the low catalyst utilization, and the activity decline owing to particle dissolution and aggregation during the operation, thus simultaneously improved Iridium mass activity, structural stability and mechanical strength will be achieved for the oxygen electrodes during operation. We believe the EU-funded 3DIr4PEMWE project will accelerate the industrialization of PEM water electrolyzer technology and realize the aspiring hydrogen energy society as soon as possible