Improving stability of iridium oxide based anodes for water electrolysis

与传统的碱性电解槽相比，聚合物电解质膜式水电解槽（PEMWE）具有许多优点，包括能够在高电流密度下运行，以及能够更好地应对间歇性使用，这将伴随使用风能和太阳能等可再生能源。虽然在减少或去除贵金属含量以催化PEMWE阳极缓慢的析氧反应（OER）方面已经做了很多工作，但阳极催化剂（IrOx/RuOx）只占PEMWE系统总成本的一小部分（3.6%）。因此，为了提高PEM电解槽的商业可行性，需要改进堆寿命。实现这一目标的主要方法之一是增加所用催化剂的稳定性。该项目将着眼于提高对OER催化剂稳定性和溶解机理的理解，并建立在酸性水介质中标准化的短期加速测试方法，从而更好地衡量PEMWE应用中OER催化剂的稳定性。目的还在于将三电极实验室测试结果与使用热制备金红石IrO2催化剂的操作中（MEA）测试结果进行比较，金红石IrO2催化剂先前已被证明是最稳定的OER。此外，它还将研究如何在保持催化剂活性的同时提高催化剂的稳定性，比如之前在特定表面位置使用混合氧化物和金属添加剂的工作。在整个项目中，将特别努力尝试将电化学数据与表面描述符联系起来，以更好地确定纳米颗粒的哪些物理特征会影响金属溶解。这些信息将有助于更好地开发电化学催化剂，这些催化剂在高电位运行时（如用于氢燃料发电的电化学水分解所需的那些催化剂）较少受到金属溶解的影响

Polymer electrolyte membrane water electrolysers (PEMWE) represent many advantages over conventional alkaline electrolysers including the ability to operate at high current density as well as being able to better cope with intermittent use that would accompany the use of renewable energy sources such as wind and solar power. While much work has been conducted on reducing or removing the noble metal content for the catalysis of the sluggish oxygen evolution reaction (OER) that occurs at the anode in PEMWE, the anode catalyst (IrOx/RuOx) represents a small percentage (3.6%) of the total cost of a PEMWE system. Therefore, to improve the commercial viability of PEM electrolysers improvements to stack lifetime are required. One of the principles ways this could be achieved is to increase the stability of the catalysts used.This project will look at improving the understanding of OER catalysts stability and dissolution mechanism as well as build on methods for standardised short term accelerated testing in aqueous acidic media that can better benchmark stability of OER catalysts for PEMWE applications. The intention is also to conduct a comparison of results obtained in three electrode laboratory testing to in-operando (MEA testing) using thermally prepared rutile IrO2 catalysts which have previously shown to be the most stable for OER. In addition, it will look at ways to improve stability of catalysts while retaining their activity such as work previously conducted on the use of mixed oxides and metal addition to specific surface sites.Throughout the project particular effort will be made to try and associate electrochemical data to surface descriptors to better determine which physical features of the nanoparticles affect metal dissolution. This information should enable better development of electrochemical catalysts that suffer less from metal dissolution when in operation at high potentials such as those required for electrochemical water splitting for hydrogen fuel generation