CAS: Bimetallic Transition Metal Phosphide Nanostructures as High-Efficiency, Earth-Abundant, and Durable Catalysts for Electrochemical Water Splitting

在化学系化学催化计划的支持下，弗吉尼亚联邦大学的Indika Arachchige和Ka Un Lao教授正在研究金属磷化物纳米颗粒的基本性质，作为将水分解为环境友好的氢和氧燃料的有效催化剂。利用电力从水中廉价地产生氢气（电化学水分解）将提供丰富的可再生燃料来源。目前，用于水裂解的最活跃的催化剂由昂贵和稀有的金属如铂组成。该项目将开发新的化学合成方法，从价格较低且储量丰富的金属磷化物中生产高效催化剂。磷化物催化剂的活性通过引入多个金属原子来改性颗粒的表面而得到改善。该研究团队将合成和催化专业知识与量子化学计算和人工智能相结合，以全面了解粒度，形状和组成对关键催化性能和化学稳定性的影响。该项目的协作性质为研究生和本科生提供多学科培训和指导，以培养催化剂设计和合成，计算化学和纳米科学方面的技能。夏季拓展到里士满公立学校暴露K-12学生的尖端纳米化学和催化项目，并开发适合年龄的纳米科学教育模块影响数百名代表性不足的少数民族学生.电催化使水分解提供了一个令人兴奋的机会，生产环保燃料为人类活动提供动力.过渡金属磷化物（TMP）已经成为用于水电解的地球丰富的催化剂，并且它们的活性可以通过掺混协同金属以改变表面亲和力以及析氢（HER）和析氧（OER）反应的动力学和机理而极大地增强。支撑其有效应用的是合理且可预测地实现精确控制的催化剂特征的能力，包括直接影响HER/OER活性、稳定性和耐久性的特定催化剂结构、表面刻面、形态和组成。该计划的目的是利用一个全面的理论和实验方法，以生产具有控制本征特征的纳米结构，作为HER和OER的高效电催化剂。通过胶体化学方法制备了一系列具有不同尺寸、组成和形貌的TMP纳米结构。协同金属合金化的电荷分布，离子吸附，氧化/还原动力学和机制，以及稳定性的影响进行了深入探讨与密度泛函理论模拟和机器学习模型的实验指导。理论指导的实验被设计成探测特定的催化剂结构、晶面、表面终止和显示出上级水裂解活性和稳定性的组合物，其与HER和OER的潜在动力学和机制相关。这些努力揭示了同时控制纳米结构、晶面、形态和组成对水裂解活性的根本影响，并开发了指导研究人员生产高效，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响进行评估来支持审查标准。

With the support of the Chemical Catalysis program in the Division of Chemistry, Professors Indika Arachchige and Ka Un Lao of the Virginia Commonwealth University are studying the fundamental properties of metal phosphide nanoparticles as effective catalysts for splitting water into environmentally friendly hydrogen and oxygen fuel. The inexpensive generation of hydrogen from water using electricity (electrochemical water splitting) would provide an abundant source of renewable fuel. Currently, the most active catalysts used in water splitting are comprised of expensive and rare metals such as platinum. This project will develop new chemical syntheses to produce efficient catalysts from metal phosphides that are less expensive and abundant. The activity of the phosphide catalysts is improved by modifying the surface of the particles by incorporating multiple metal atoms. The research team combines synthesis and catalysis expertise with quantum chemistry calculations and artificial intelligence to garner a thorough understanding of the effects of particle size, shape, and composition on key catalytic properties and chemical stability. The collaborative nature of this project provides multidisciplinary training and mentoring for graduate and undergraduate students, to develop skills in catalyst design and synthesis, computational chemistry, and nanoscience. The summer outreach to Richmond Public Schools exposes K-12 students to cutting-edge nanochemistry and catalysis projects, and develops age-appropriate nanoscience educational modules impacting hundreds of underrepresented minority students.Electrocatalysis enabled water splitting presents an exciting opportunity to produce environmentally benign fuel to power human activities. Transition metal phosphides (TMPs) have emerged as earth abundant catalysts for water electrolysis and their activity can be enormously augmented by admixing synergistic metals to modify the surface affinity and the kinetics and mechanisms of hydrogen (HER) and oxygen evolution (OER) reactions. Underpinning their efficient application is the ability to rationally and predictably achieve precisely controlled catalyst features, including specific catalyst structures, surface facets, morphologies, and compositions, that directly impact the HER/OER activity, stability, and durability. The objective of this program is to exploit a comprehensive theoretical and experimental approach to produce bimetallic TMP nanostructures with control over intrinsic features as high efficiency electrocatalysts for HER and OER. A series of TMP nanostructures having various sizes, compositions, and morphologies are produced by colloidal chemistry methods. The influences of synergistic metal alloying on charge distribution, ion adsorption, oxidation/reduction kinetics and mechanisms, and stability are thoroughly probed with experiments guided by density functional theory simulations and machine learning models. The theory-guided experiments are designed to probe specific catalyst structures, crystal facets, surface terminations, and compositions that show superior water splitting activity and stability, which are correlated to underlying kinetics and mechanisms of HER and OER. These efforts reveal the fundamental influences of simultaneous control over nanostructure, crystal facets, morphology, and composition on water splitting activity and develop roadmaps that guide researchers to produce highly efficient, robust TMP nanocatalysts for the rational design of electrochemical reactors.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.