Multi-metallic electrocatalysts with engineered nanoscale features and well-defined crystallographic orientation

具有工程纳米级特征和明确晶体取向的多金属电催化剂

• 批准号: RGPIN-2015-05821
• 负责人: Guay, Daniel
• 金额: $ 5.39万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=707955
• 关键词: Multi; metallic; electrocatalysts; engineered; nanoscale

The world energy consumption has continuously increased over the past years and is expected to grow unabated in the future. Innovation in and development of alternative energy sources, such as fuel cells, are absolutely fundamental to helping the world meet its energy needs, and reducing its dependency on fossil fuels with its concomitant emissions of greenhouse gases. However, significant challenges associated with the performance, cost, and reliability of materials must be addressed prior to fully implementing these technologies. The issue of stability is the fundamental reason for the general lack of success in identifying viable alternatives to Pt-based ORR catalysts. Very few materials may be considered, as the majority of metals are unstable in the acidic oxidative environment of a PEMFC cathode. This situation is radically different in alkaline solutions, and both Ag and Au possess superior electrochemical stability than Pt in base. Accordingly, Ag- and Au-based electrocatalysts may constitute interesting alternatives to Pt for the ORR in alkaline environments, and will be studied. To do so, we will use model systems obtained through epitaxial growth on oriented MgO substrates. Three different orientations will be investigated, namely (111), (110) and (100). The bimetallic systems of interest have been selected on the basis of the most recent density-functional theory calculations. In the case of Ag, these calculations predict that alloys of Ag with Cu, Ni, Co and Fe should bind the OOH intermediate more strongly than pure Ag, and therefore should exhibit better ORR characteristics in alkaline solutions than pure Ag. In the case of Au, the same calculations indicate that modification of the heat of adsorption of the O-species may be performed by mixing Au with solute elements. The early transition metal elements Sc, Ti, La and Y have been identified as the most promising. Accordingly, Pulsed Laser Deposition (PLD) will be used to prepare epitaxial films with (111), (110) and (100) surface orientations comprised of AgM (with M = Cu, Ni, Co and Fe) and AuM (with M = Sc, Ti, La and Y) bimetallic compounds. The PLD deposition technique will be used to achieve this, as it allows for the deposition of all elements, along with the formation of kinetically stable (metastable) alloys, due to the instantaneous deposition rate. This project is expected to lead to the identification of new materials with improved electrocatalytic activity and stability for the ORR in alkaline solutions. The prospect of identifying new Ag-based electrocatalyst materials is particularly appealing, considering the cost of Ag is sixty-five times lower than that of Pt. This may alleviate one of the technological barriers to the eventual commercialization of alkaline fuel cells.

在过去的几年中，世界能源消耗不断增加，预计将来会不会减弱。替代能源（例如燃料电池）的创新和开发是帮助世界满足其能源需求的绝对至关重要的，并降低了其对化石燃料的依赖，其随之而来的温室气体排放。但是，在完全实施这些技术之前，必须解决与材料的性能，成本和可靠性相关的重大挑战。 稳定的问题是总体上缺乏成功识别基于PT的ORR催化剂的可行替代方案的基本原因。很少有人可以考虑材料，因为大多数金属在PEMFC阴极的酸性氧化环境中是不稳定的。这种情况在碱性溶液中截然不同，而Ag和Au具有优越的电化学稳定性。因此，基于AG和AU的电催化剂可能构成碱环境中ORR的PT替代品，并将研究。 为此，我们将使用通过面向MGO底物上的外延生长获得的模型系统。将研究三种不同的方向，即（111），（110）和（100）。双金属感兴趣的系统是根据最近的密度功能理论计算选择的。 在AG的情况下，这些计算预测，与Cu，Ni，Co和Fe的Ag合金应比纯Ag更强烈地结合OOH中间体，因此在碱性溶液中应表现出更好的ORR特性。 在AU的情况下，相同的计算表明，可以通过将AU与溶质元素混合来进行O种的吸附热的修饰。早期过渡金属元素SC，Ti，La和Y已被确定为最有前途的。 因此，脉冲激光沉积（PLD）将用于制备由AGM组成的（带有M = Cu，Ni，Co和Fe）和AUM（带有M = SC，Ti，Ti，La和Y）Bimetallic Compounds的（111），（110），（110）和（100）表面取向。 PLD沉积技术将用于实现这一目标，因为它允许所有元素的沉积以及动力学稳定（亚稳态）合金的形成，这是由于瞬时沉积速率。 预计该项目将导致鉴定具有碱性溶液中ORR的电催化活性和稳定性的新材料。考虑到AG的成本比PT低65倍，鉴定新的基于Ag的电催化剂材料的前景特别有吸引力。这可能减轻碱性燃料电池最终商业化的技术障碍之一。