CAS: Investigations of Monometallic, Bimetallic and Dual-Anion Transition Metal X-ide Water Oxidation Electrocatalysts

在化学系化学催化项目的支持下，德克萨斯大学奥斯汀分校的Charles B. Mullins教授将研究促进和提高水分子电化学分解产生氧气效率的材料。这是电化学水分解制氢过程中最重要和最具限制性的化学反应。目前，氢在许多重要的工业化学过程中被大量使用，预计它将在未来的清洁能源生产中发挥更大的作用。随着全球人口的增长和欠发达国家的现代化，未来30年世界能源需求将翻一番。电化学水分解将在清洁能源生产中发挥重要作用，以满足这一需求。除了要发现的重要科学之外，Mullins和他的团队将(i)为8-12年级的学生制作一个关于能源的动画视频，以帮助激励这些学生提高科学素养，（ii）让代表性不足的群体的研究人员参与这项研究，以扩大参与范围，以及（iii）将获得的结果传达给更广泛的科学界和公众，以便这项工作能够产生最大的影响。在这个项目中，德克萨斯大学奥斯汀分校的Charles B. Mullins教授和他的研究小组将研究将各种类型的金属X-ide（如碳化物、硫族化物、嘌呤和硼化物）材料转化为高活性的电催化剂（即金属氧化物/（氧）氢氧化物对应物）。在这样做的过程中，一个关键问题将是原位自氧化如何影响析氧反应（OER）性能控制因素，如活性表面积、电导率、偶然的铁掺入等。该团队还将研究在OER过程中没有明显自氧化的X-ide催化剂的水氧化电催化。通常，这些性能控制因素是复杂地交织在一起的。为了从测量的OER活性中解卷积感兴趣的因素，Mullins和同事将在高真空条件下通过靶X-ide组分的气相沉积来制造具有良好控制形状、厚度、化学计量和晶体结构的X-ide薄膜。所获得的薄膜将用许多不同的非原位表征技术以及一系列电化学方法进行探测。为了更深入地了解模型OER系统，Mullins和团队将在OER测试期间进行现场测量，彻底进行OER后X-ide材料的物理化学表征，并进行计算研究。通过这些系统的研究，研究人员希望能够为设计金属X-ide电催化剂提供一些通用的指导，从而提出可能在能量转导领域找到广泛应用的方案。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Charles B. Mullins of the University of Texas-Austin will be studying materials to facilitate and increase the efficiency of the electrochemical decomposition of water molecules to make oxygen. This is the most important and limiting chemical reaction involved in electrochemical water-splitting to produce hydrogen. Currently hydrogen is heavily used in many industrially important chemical processes and it is anticipated to play a larger role in clean energy production in the future. The energy needs of the world will double over the next ~30 years as the global population increases and underdeveloped nations modernize. Electrochemical water-splitting will play a substantial role in clean energy production to serve this need. In addition to the important science to be uncovered, Mullins and his team will (i) create an animated video regarding energy for grade 8-12 students to assist in motivating these students to become more scientifically literate, (ii) involve researchers from underrepresented groups in this research to broaden participation, and (iii) communicate the results obtained to the broader scientific community and to the general public so that the work can have maximal impact. In this project, Professor Charles B. Mullins and his research group at the University of Texas-Austin will be studying the transformation of various types of metal X-ide (e.g., carbides, chalcogenides, pnictides, and borides) materials into highly active electrocatalysts (i.e., metal oxide/(oxy)hydroxide counterparts). In so doing, a key question will be how the in situ self-oxidation affects the oxygen evolution reaction (OER) performance-governing factors such as active surface area, electrical conductivity, incidental iron incorporation, and so forth. The team will also investigate the water oxidation electrocatalysis of X-ide catalysts which show no apparent self-oxidation during OER. Generally, these performance governing factors are complexly intertwined. To deconvolute the factor of interest from the measured OER activity, Mullins and coworkers will fabricate X-ide films with well-controlled shape, thickness, stoichiometry, and crystal structure via vapor deposition of target X-ide components under high vacuum conditions. The as-obtained films will be probed with many different ex situ characterization techniques as well as with an array of electrochemical methods. To more deeply understand model OER systems, Mullins and team will perform in situ measurements during OER testing, thoroughly undertake physicochemical characterization of post-OER X-ide materials, and perform computational studies as well. Through these systematic investigations, the investigators aspire to be able to provide some universal guidance for designing metal X-ide electrocatalysts, thereby putting forward protocols that could then potentially find broad application in the field of energy transduction.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.