EAGER: Nanostructure-Enabled Solution Catalysis with Concentration Gradients

美国国家科学基金会化学部的化学催化项目资助了加州大学洛杉矶分校的刘冲博士，以探索新的化学和反应性的溶液催化，其中反应物和催化剂的浓度是在空间中控制的。从基础研究到工业制造的化学转化通常在溶液中进行。各种化学物质均匀地分散在溶液中，这通常是正确的。虽然这通常简化了化学过程，但它也可能是一种限制。例如，一些反应物可能彼此不相容，它们的反应导致不希望的副反应和浪费。在这些情况下，把这些物种分开是有利的。刘博士正在利用纳米级导线阵列的电化学技术来完成这一挑战。这项工作的成功实施可能会为化学合成提供一个涉及纳米科学、电化学和催化的多方面方法的新范例。刘博士的研究团队，包括女性和来自弱势群体的学生，将在这个项目中从事高度跨学科的研究。刘博士和他的团队假设纳米线阵列的电化学在微观上产生可控的局部O2梯度，这使得对O2敏感的有机金属催化剂能够进行氧化反应，如甲烷（CH4）直接转化为甲醇（CH3OH）。刘博士的研究小组将设计和表征由线阵列电极产生的浓度梯度，在环境条件下，用O2氧化剂建立选择性的ch4到ch3oh的O2失活催化剂，并探索从浓度梯度中受益的溶液催化的其他场景。本项目通过解决两个重要问题，建立了具有浓度非均质性的均相催化的设计原则：(1)如何在微观尺度上使用电位来控制和产生预先设计的浓度曲线？(2)通过建立微观浓度梯度，溶液催化可以得到哪些改进？纳米科学和均相催化的整合提供了一种独特的、潜在的强大方法来控制分子和微观长度尺度的反应。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 this award, the Chemical Catalysis Program of the NSF Division of Chemistry is funding Dr. Chong Liu of the University of California, Los Angeles to explore new chemistry and reactivity in solution catalysis where the concentrations of reactants and catalysts are controlled in space. Chemical transformations ranging from fundamental investigations to industrial manufacturing are often conducted in solution. It is usually true that the various chemical species are uniformly dispersed throughout the solution. While this often simplifies chemical processes it can also be a limitation. For example, some reactants may not be compatible with each other, with their reactions leading to undesirable side reactions and waste. In these cases it is advantageous to keep these species separated. Dr. Liu is accomplishing this challenge with electrochemistry using arrays of nanometer scale wires. Successful implementation of the proposed work would potentially offer a new paradigm in chemical synthesis with a multifaceted approach involving nanoscience, electrochemistry, and catalysis. Dr. Liu's research team, including women and students from underrepresented groups, will be engaged in highly interdisciplinary research in this project. Dr. Liu and his team hypothesize that the electrochemistry of nanowire arrays yields controllable local O2 gradient microscopically, which enables O2-sensitive organometallic catalysts to perform oxidative reactions such as direct methane (CH4) to methanol (CH3OH) conversion. Dr. Liu’s research group will design and characterize concentration gradients generated by wire array electrodes, establish a selective CH4-to-CH3OH conversion of O2-deactivating catalysts with O2 oxidant at ambient condition, and explore additional scenarios of solution catalysis that benefits from concentration gradients. This project establishes the design principle of homogenous catalysis with concentration heterogeneity, by addressing two important questions: (1) How can one use electric potential to control and generate a pre-designed concentration profile at microscopic scale? (2) What improvements can be attained for solution catalysis via the establishment of microscopic concentration gradients? The integration of nanoscience and homogenous catalysis provides a unique and potentially powerful approach to control reactions at both molecular and microscopic length scalesThis 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.