Synthesis and Characterization of Nanoscale Transition Metal Phosphates as a New Class of Electrocatalysts

[0731132]徐军John本工作主要研究了纳米级过渡金属磷酸盐作为电化学氧还原反应（ORR）和出氧反应（OER）的一类新型非贵金属电催化剂的合成和表征。PI的实验室最近发现，某些过渡金属磷酸盐对ORR和/或OER表现出优异的催化活性，其中一些能够有效地催化ORR和OER，因此是有前途的双功能氧电催化剂。研究将建立在最初的发现和努力的基础上：(1)合成纳米级过渡金属磷酸盐作为ORR和OER的一类新的非贵金属电催化剂；(2)研究纳米级催化剂的内在催化活性和构效关系；(3)利用原位同步加速器x射线吸收精细结构（XAFS）技术探索其催化机理。创新的合成技术将被开发，以合成颗粒尺寸小到几纳米的过渡金属磷酸盐催化剂。从初步结果来看，这种纳米级催化剂可能会对ORR和OER产生相当非凡的催化活性。它们将为探索催化机制、扩大我们对这些反应的纳米级非贵金属电催化剂的理解和最终使用，构成极好的系统。电化学技术将研究它们的催化性能、ORR和OER动力学，XAFS技术将研究它们的原子、电子和表面结构以及与催化性能的相关性。现场XAFS方法将被设计用于在模拟燃料电池和水电解槽中ORR和OER的实际操作条件下，探索它们的催化机制以及稳定性和耐久性问题。这项研究的智力价值如下。它有望产生一类新的高活性纳米级非贵金属电催化剂用于ORR和OER，并推进我们对这些具有基础和技术意义的重要反应的非贵金属电催化剂的催化机理和结构-性能关系的基本理解。它还有望为纳米级电催化剂的创新合成方法和新的原位表征技术的发展做出贡献。该研究的更广泛影响如下。这种新型纳米级电催化剂可以在碱性燃料电池、水电解电池、金属-空气电池和电化学氧传感器中得到重要应用。它们对所谓的氢经济的发展尤其有价值，因为水电解产生氢和燃料电池利用氢的廉价和可行的非贵金属电催化剂是潜在实现氢经济的最理想材料之一。这项研究将进一步加强PI与其所在机构罗格斯大学、高级合作者Mahalingam Balasubramanian博士及其所在机构阿贡国家实验室之间的合作。参与研究的学生将能够利用ANL最先进的仪器，他们的教育将通过大学和国家实验室环境的经验得到加强和丰富。拟议的研究将为妇女和代表人数不足群体的个人参与提供极好的机会。此外，PI将邀请当地高中生参观并参与研究。这项研究的结果将被纳入PI在罗格斯大学推出的两门新的跨学科课程的教材中。合成、物理和电化学表征以及催化性能的研究将在罗格斯大学的PI实验室进行。通过PI和Balasubramanian博士之间的合作，XAFS对原子、电子和表面结构以及分子水平催化机制的研究将在阿贡国家实验室的先进光子源（APS）进行，Balasubramanian博士是APS的光束线科学家，在XAFS方法方面具有广泛的专业知识，并利用它们研究电化学材料。PI和Balasubramanian博士在过去几年中进行了非常有益的科学合作。Balasubramanian博士的参与是由APS全额资助的，他在科学和财政上利用了拟议的努力。

0731132 Xu, Jun John This work focuses on synthesis and characterization of nanoscale transition metal phosphates as a new class of non-noble-metal electrocatalysts for the electrochemical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The PI's laboratory recently discovered that certain transition metal phosphates exhibit excellent catalytic activities for ORR and/or OER, and some of them are capable of effectively catalyzing both ORR and OER and hence are promising bi-functional oxygen electrocatalysts. The research will build upon the initial discovery and endeavor to (1) synthesize nanoscale transition metal phosphates as a new class of non-noble-metal electrocatalysts for ORR and OER; (2) investigate the intrinsic catalytic activity and structure-property relationships of the nanoscale catalysts; and (3) probe their catalytic mechanisms using in-situ synchrotron X-ray Absorption Fine Structure (XAFS) techniques. Innovative synthesis techniques will be developed to synthesize transition metal phosphate catalysts of particle size down to a few nanometers. Judging from preliminary results, such nanoscale catalysts may give rise to rather extraordinary catalytic activities for ORR and OER. They would constitute excellent systems for probing catalytic mechanisms and expanding our understanding, and eventual use, of nanoscale non-noble-metal electrocatalysts for these reactions. Their catalytic properties and ORR and OER kinetics on them will be investigated with electrochemical techniques, and their atomic, electronic and surface structures will be investigated with XAFS techniques and correlated with catalytic properties. In-situ XAFS methods will be designed to probe their catalytic mechanisms and stability and durability issues under conditions mimicking real-operating conditions for ORR and OER in fuel cells and water electrolyzers. The intellectual merits of the study are the following. It promises to give rise to a new class of highly active nanoscale non-noble-metal electrocatalysts for ORR and OER, and advance our fundamental understanding of catalytic mechanisms and structure-property relationship of non-noble-metal electrocatalysts for these fundamentally and technologically important reactions. It also promises to contribute to the development of innovative synthesis methods for nanoscale electrocatalysts and novel in-situ characterization techniques. The broader impacts of the study are the following. The new class of nanoscale electrocatalysts could find important applications in alkaline fuel cells, water electrolysis cells, metal-air batteries and electrochemical oxygen sensors. They could especially be of value to the development of the so-called hydrogen economy, as inexpensive and viable non-noble-metal electrocatalysts for water electrolysis to produce hydrogen and for fuel cells to utilize hydrogen are among the most desirable materials to potentially enable the hydrogen economy. The study will further enhance collaboration between the PI and his institution, Rutgers University, and the senior collaborator, Dr. Mahalingam Balasubramanian, and his institution, Argonne National Laboratory. Students involved in the research will be able to utilize the state-of-the-art instrumentation at ANL and their education will be enhanced and enriched with experience at both university and national lab settings. The proposed study will offer excellent opportunities for participation by women and individuals from underrepresented groups. Moreover, the PI will invite local high school students to visit and participate in the research. The findings of the research will be incorporated into teaching materials for two new interdisciplinary courses that the PI has introduced at Rutgers University. Synthesis, physical and electrochemical characterization and studies of catalytic properties will be carried out in the PI's laboratory at Rutgers University. XAFS investigations of atomic, electronic and surface structures and molecular-level catalytic mechanisms will be carried out at the Advanced Photon Source (APS) of the Argonne National Laboratory, through collaboration between the PI and Dr. Balasubramanian, who is a beamline scientist at the APS with extensive expertise in XAFS methods and employing them to study electrochemical materials. The PI and Dr. Balasubramanian have had highly rewarding scientific collaboration in the past few years. The participation by Dr. Balasubramanian, who is fully funded through the APS, leverages the proposed effort both scientifically and financially.