Collaborative Research: SusChEM: Manipulation of Reaction Selectivity in the electrochemical environment for biomass-to-chemicals conversions

在生物质转化为化学品的电化学环境中操纵反应选择性是可持续满足能源和商品需求的一种很有前途的手段。生物质是一种“碳中性”原料，因为它是通过吸收大气中的二氧化碳来生长的，而只消耗太阳能。该项目正在寻找新的有效途径，从目前难以加工的生物质成分中生产有用的化学品。虽然目前大多数生物质转化都是使用催化剂和热能进行的，但这项工作正在利用电力驱动的催化反应的独特方面，以实现在低温和压力下合成有用的化学品。反过来，这些过程所需的电力可能来自风能和太阳能等可再生能源。正在采取一种基本的方法，将探索催化反应性质的实验技术与计算机模拟相结合，以建立控制反应选择性的因素的综合图景，并设计更有效的过程。这项工作的见解在扩大绿色化学的范围方面有更广泛的应用。这项研究也被用来促进科学教育，让本科生研究人员参加暑期实习，国际和平研究所还在开发一系列与理解电催化反应的物理过程有关的互动教育模块。该项目正在研究对生物质原料转化为所需化学目标的选择性的电化学控制。电化学转化在可持续加工中具有优势，因为它们通常在低温下运行，并直接利用含水原料。本工作以呋喃和5-羟甲基呋喃在铂电极上的选择性氧化为探针体系，研究了通过控制电极电位和组成来控制选择性的不同机理。正在探索的机制包括电荷转移反应相对于中性原子转移反应的区别，氧和有机物种表面覆盖度的变化，以及具有特定反应性或几何构型的促进剂的作用。目前正在整合三种互补的研究方法来描述这些影响。金属催化剂的电化学动力学测量与原位光谱相结合确定了反应路径；表面科学实验在模型铂(111)表面上详细研究了氧化的基本步骤；最后，密度泛函理论计算研究了相同的表面化学，包括电位效应和水-金属界面的模拟。这三项研究提供了互补的信息，丰富了对电化学环境的深入了解。这项工作在拓展绿色化学和电化学合成路线的范围方面有更广泛的应用。这项研究也被用来促进科学教育，让本科生研究人员参加暑期实习，国际和平研究所还在开发一系列与理解电催化反应的物理过程有关的互动教育模块。

Manipulation of reaction selectivity in the electrochemical environment for biomass-to-chemicals conversions Fuels and chemicals derived from plant matter (biomass) are a promising means to sustainably meet demands for energy and commodity products. Biomass is a "carbon neutral" feedstock because it grows by incorporating CO2 from the atmosphere while only consuming solar energy. This project is finding new and efficient outlets to generate useful chemicals from components of biomass that are currently difficult to process. While most biomass conversions are presently performed using catalysts and energy supplied by heat, this work is exploiting unique aspects of electricity-driven catalytic reactions in order to achieve synthesis of useful chemicals at low temperatures and pressures. The electricity required for these processes may, in turn, be derived from renewable sources such as wind and solar. A fundamental approach is being taken in which experimental techniques that probe the nature of the catalytic reactions are combined with computer simulations to build a comprehensive picture of the factors that govern reaction selectivity and to design more efficient processes. Insights from this work have broader application in extending the scope of green chemistry. This research is also being used to promote science education by involving undergraduate student researchers for summer internships, and the PI's are additionally developing a series of interactive educational modules related to understanding the physical processes governing electro-catalytic reactions. This project is investigating electrochemical control over selectivity in the conversion of biomass-derived feedstocks to desired chemical targets. Electrochemical conversions offer advantages in sustainable processing since they generally operate at low temperatures and utilize aqueous feedstocks directly. Using selective oxidation of furfural and 5-hydroxymethyl furfural over Pt electrodes as probe systems, this work focuses on determining the different mechanisms by which selectivity can be manipulated through control over electrode potential and composition. Mechanisms being explored include differentiation of charge-transfer reactions relative to neutral atom transfer reactions, variation in surface coverage of oxygen and organic species, and the role of promoters with specific reactivity or geometry. Three complementary research approaches are being integrated to characterize these effects. Measurement of electrochemical kinetics on metal catalysts is combined with in-situ spectroscopy to identify reaction pathways; surface science experiments are used on a model Pt(111) surface to study oxidation elementary steps in detail; and finally, density functional theory calculations are used to investigate the same surface chemistry, including simulation of electric potential effects and the water-metal interface. The three research thrusts provide complementary information and enrich the depth of understanding of the electrochemical environment. Insights from this work have broader application in extending the scope of green chemistry and electrochemical synthetic routes. This research is also being used to promote science education by involving undergraduate student researchers for summer internships, and the PI's are additionally developing a series of interactive educational modules related to understanding the physical processes governing electro-catalytic reactions.