Single-atom (SA) decoration of 1D semimetallic titania nanostructures (STN): a conductive electrode for electrocatalytic hydrogen evolution (HER)

氢（H2）是未来最有前途的可再生清洁能源形式。目前，工业制氢是基于天然气的重整，这在产生二氧化碳的同时使用了大量的不可再生能源。电化学水分解是一种可持续、环保的制氢方法。因此，提高电化学水分解的效率和经济性是世界各国研究的首要目标。催化剂的存在可以将析氢反应（HER）所需的过电位降至最低，这对于提高水分解效率至关重要。铂是最著名的HER催化剂，主要是因为它需要非常小的过电位。然而，Pt的高成本和稀缺性限制了其广泛的技术应用。通过为HER设计新的催化剂材料，研究人员旨在扩大他们对控制HER稳定性和活性的性质和表面结构的理解。目前的研究计划旨在使用单原子（SA）修饰的半金属钛基纳米腔（STN）作为HER的非昂贵和高效电极，创造一种新的和高度定义的电催化制氢平台，具有提高活性和长期稳定性。该方法的关键新颖之处在于将缺陷工程的基于钛的半金属纳米结构与先进的单原子装饰策略相结合，制造了一个平台，用于绿色H2生产行业的HER电极。预计三种黄金特征的协同效应，即1)一维背接触（1D）结构中的定向电荷转移，2)单原子修饰和3)SA-STN组件中表面暴露的Ti3+中心，将导致HER活性的提高。作为概念验证，在项目的最后一个工作包中，我们的目标是将优化的HER电极植入商用聚合物电解质膜（PEM）电解槽中，这将提供关于电极在标准和现场测量条件下的长期活性和稳定性的基准信息。

Hydrogen (H2) is the most promising future form of renewable clean energy source. Currently, industrial H2 production is based on reforming natural gas, which uses a high amount of non-renewable energy while producing carbon dioxide. A sustainable and environmentally friendly H2 production approach is electrochemical water splitting. Therefore, enhancing the efficiency and improving the economic aspects of electrochemical water splitting is a primary goal of research worldwide. The presence of a catalyst to minimize the overpotential required for the H2 evolution reaction (HER) is essential to enhance the efficiency of water splitting. Platinum is the most well-known catalyst for HER, mainly due to the fact that it requires very small overpotentials. However, the high cost and scarcity of Pt restrict its prevalent technological use. By designing new catalyst materials for the HER, researchers aim to expand their understanding of the properties and surface structures that govern HER stability and activity. The present research proposal aims at creating a novel and highly defined platform for electrocatalytic hydrogen generation using Single-Atom (SA) decorated Semimetallic Titania-based Nanocavities (STN) as a non-expensive and highly efficient electrode for HER with boosted activity and long-term stability. The key novelty of the proposed approach is the combination of defect-engineered titania-based semimetallic nanostructures with the advanced single-atom decoration strategy to fabricate a platform to be employed as an HER electrode in the green H2 production industry. It is expected that the synergistic effect of three golden features, i.e., i) directional charge transfer in a one-dimensional back contacted (1D) structure, ii) single atom decoration, and iii) surface-exposed Ti3+ centers in an SA-STN assembly, will lead to a boosted HER activity. As a proof of concept, in the last work package of the project, we aim to implant the optimized HER electrode in a commercial polymer electrolyte membrane (PEM) electrolyzer, which will provide benchmark information regarding the long-term activity and stability of the electrode in a standard and onsite measurement conditions.