ERI: Engineering a Bi-Functional Heterostructured Photocatalyst for CO2 Photoconversion

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。对清洁能源的需求，加上全球对减少温室气体（特别是化石燃料燃烧产生的二氧化碳）排放的需求，为可持续的低碳排放技术的研究提供了强大的动力。该项目利用可见光太阳能将废弃的二氧化碳（CO2）反应为甲醇和甲酸等增值化学品。迄今为止，相关的研究工作受到产物选择性低、仅限于紫外光区以及光催化机制不高效的阻碍。为了克服这些限制，该项目将研究一种称为异质结的双功能光催化剂设计。该异质结由光热半导体光催化剂与金属有机骨架（MOF）材料界面组成。在异质结结构中集成这两个组件可以增强二氧化碳的捕获和转化为增值化学品。除了技术方面，该项目还将包括教育和推广活动，旨在激发学生对STEM职业的兴趣，重点是女性和其他未被充分代表的群体在科学和工程领域的机会。该项目的总体目标是设计一种双功能异质结构光催化剂，用于利用可见光能量进行高效的CO2光转换。该项目建立在MOF成分将增强二氧化碳吸收并提供促进进入光催化剂催化位点所需的孔隙空间的假设之上。在可见光照射下，来自光催化剂的光激发电子会将二氧化碳还原为所需的碳氢化合物产物。该项目包括四个目标：1)合成和表征不同粒径和核壳性质的MIL-101(Cr)-NH2 MOF和carbon@TiO2光催化剂家族；2)开发一种策略来介导MOF在光催化剂表面的生长；3)探测carbon@TiO2@MIL-101(Cr)-NH2光催化剂的界面结构；4)研究界面结构对光热催化CO2转化为C1烃的选择性控制和机理的影响。carbon@TiO2光催化剂设计的一个关键特征是通过与碳核相关的热捕获和转移结合TiO2壳层的光收集和光电子产生特性来提高光热效率。为了实现这四个目标，将采用各种方法，包括一系列光电化学技术、光谱方法、控制和反应实验以及产品分析。光催化剂和MOF的性质将在合成的每个阶段进行表征，直至并包括集成异质结设计中组成材料的双功能性能。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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Demand for clean energy, combined with the global need for decreased emissions of greenhouse gases (especially carbon dioxide from fossil fuel combustion), has generated strong research impetus for sustainable, low carbon emission technologies. The project utilizes visible-light solar energy to react waste carbon dioxide (CO2) to value-added chemicals such as methanol and formic acid. Related research efforts to date have been hampered by low product selectivity, limitation to the UV light region, and inefficient photocatalytic mechanisms. To overcome those limitations, the project will investigate a bifunctional photocatalyst design known as a heterojunction. The heterojunction consists of a photothermal semiconductor photocatalyst interfaced with a metal-organic framework (MOF) material. Integrating the two components in the heterojunction architecture enhances both the capture and conversion of CO2 to value-added chemicals. Beyond the technical aspects, the project will include educational and outreach activities designed to excite students about careers in STEM, with emphasis on opportunities for women and other underrepresented groups in science and engineering.The overall project goal is to engineer a bi-functional heterostructured photocatalyst for efficient CO2 photoconversion utilizing visible-light energy. The project is built on the hypothesis that the MOF component will enhance the CO2 uptake and provide the pore space needed to promote access to the catalytic sites on the photocatalyst. Under visible light irradiation, the photoexcited electrons from the photocatalyst will then reduce CO2 to the desired hydrocarbon products. The project includes four aims: 1) synthesize and characterize families of MIL-101(Cr)-NH2 MOF and carbon@TiO2 photocatalyst of various particle size and core-shell properties; 2) develop a strategy to mediate MOF growth on the surface of the photocatalyst; 3) probe the interfacial structures of the carbon@TiO2@MIL-101(Cr)-NH2 photocatalyst; and 4) investigate the impact of the interface architecture on both selectivity control and the mechanism of photothermal catalytic CO2 conversion to C1 hydrocarbons. A key feature of the carbon@TiO2 photocatalyst design is to promote photothermal efficiency via the heat capture and transfer associated with the carbon core combined with the light-harvesting and photoelectron-generating properties of the TiO2 shell. Various methods will be employed in pursuing the four aims, including a range of photoelectrochemical techniques, spectroscopic methods, control and reaction experiments, and product analyses. Properties of the photocatalyst and MOF will be characterized at each stage of synthesis, up to and including the bifunctional performance of the component materials in the integrated heterojunction design.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.