EPRI: Collaborative Research: Hydrogen Production via Electrochemical Reforming of Ethanol in a Proton Exchange Membrane Cell

生物质和/或生物燃料制氢已被提议作为目前利用甲烷和煤炭等化石燃料制氢和利用可再生能源(如太阳能和风能)制氢之间的一种过渡方法。该项目旨在开发一种通过乙醇电化学重整反应(EER)在质子交换膜(PEM)电池中生产氢气的高能效工艺。乙醇是一种有吸引力的制氢原料，因为其现有的基础设施可以从生物质中大规模生产。这项工作将探索将部分氧化的贵金属催化剂用作一类新的阳极催化剂，以实现快速反应动力学(快速电荷转移)和高效率。在质子交换膜电池中研究EER过程中的制氢过程，其中析氢反应发生在阴极，而限速乙醇氧化反应发生在阳极。这些假设是：(1)部分氧化贵金属(MOX)的晶格氧比吸附的OH(水作为电催化中常见的氧化剂的解离产物)更能有效地去除有毒物种；(2)与贵金属(M)和O组分的特殊排列有关的系综效应可能对乙醇的C-C裂解起重要作用。这些假说将通过理论和实验相结合的研究来验证：将用密度泛函理论(DFT)计算来研究片状和纳米颗粒形式的部分氧化贵金属(MOX、M：PT、Rh、Ir、Pd和Ru)对C-C裂解的稳定性和反应性。DFT计算预测，MOX团簇的溶液相合成将对乙醇的完全氧化具有高效率。星团的结构特征将使用各种技术进行，包括国家实验室的像差校正扫描电子显微镜和X射线吸收光谱(XAS)。将在半电池和单电池中评估EER动力学，由此计算能量效率、氢气和二氧化碳生成率以及选择性，并用于评估所建议的MOX催化剂的性能

Production of hydrogen from biomass and/or biofuels has been proposed as an interim method between the current hydrogen production from fossil fuels, such as methane and coal, and hydrogen production using renewable sources (e.g., solar and wind). This project aims to develop a highly energy-efficient process for hydrogen production in a proton exchange membrane (PEM) cell via the ethanol electrochemical reforming reaction (EER). Ethanol is an attractive feedstock for hydrogen production because of the existing infrastructure for its large-scale production from biomass. The proposed work will investigate the use of partially oxidized noble metal catalysts as a new group of anode catalysts enabling fast reaction kinetics (rapid charge transfer) and high efficiency. The production of hydrogen by the EER process will be studied in a PEM cell, where the hydrogen evolution reaction happens at the cathode and the rate-limiting ethanol oxidation reaction happens at the anode. The hypotheses are: (1) Lattice oxygen from partially oxidized noble metals (MOx) will be more active to remove poisoning species than adsorbed OH (the dissociative product of water acting as a common oxidant in electro-catalysis); (2) The ensemble effect, associated with particular arrangements of the noble metal (M) and O constituents, may play an important role towards the C-C splitting of ethanol. The hypotheses will be tested by a combination of theoretical and experimental investigations: Density functional theory (DFT) calculations will be performed to study the stability and reactivity towards C-C splitting on partially oxidized noble metals (MOx, M: Pt, Rh, Ir, Pd and Ru) in slab and nanoparticle forms. Solution phase synthesis of MOx clusters, predicted by DFT calculations to have high effectiveness for complete oxidation of ethanol, will be performed. Structural characterization of the clusters will be performed using a variety of techniques, including aberration-corrected scanning transmission electronic microscopy and X-ray absorption spectroscopy (XAS) at National Laboratories. EER kinetics will be evaluated in both half-cells and single-cells, from which energy efficiency, hydrogen and carbon dioxide generation rates, and selectivity will be calculated and used to evaluate the performance of the proposed MOx catalysts