EAGER: Photocatalytic extension of short-chain molecules for biomass conversion

该项目研究了一种可持续的过程，该过程使用太阳能驱动的催化反应将生物质转化为碳氢化合物化学品。 这个过程使用了一种新的催化材料，可以产生小的活性分子，这些分子联合收割机可以结合成10-20个碳原子的大分子，就像柴油和喷气燃料中的分子一样。 通过使用生物可再生原料与太阳能驱动的化学加工相结合，该项目可以为利用生物质生产燃料和高价值化学品的近零温室气体技术奠定基础。 该项目包括一个新的外展计划，教育高中学生在当前的科学问题，并提供机会，让他们成为代言人，传达这些问题，以更广泛的公众。最近报道，光催化，使室温下的2，5-二甲基呋喃（2-5 DMF）和2-甲基呋喃（2-MF）的双碳碳偶联，同时产生氢气。 然而，该方法具有低转化率和差的选择性，以及对氧的敏感性。基础机制（即甲基的C-H活化产生的自由基物质将与呋喃环共振并导致各种异构体产物）被认为是这一重要缺陷的关键原因。最近，一位研究人员发现，在光电化学条件下，Ta 3 N5可以实现一种替代的基于自由基的途径，不仅效率高，而且对环境空气中的H2O或O2等杂质不敏感。 该项目将把这些研究扩展到光催化生物质转化。为此，需要详细了解反应机理。 机理研究将包括光暗实验，详细的产品表征，以及各种自由基发生器和受体物种的实验。 此外，还将对用作光电极的Ta 3 N5和用作多相光催化剂的Ta 3 N5进行比较，在某些情况下还包括铂等助催化剂。该奖项反映了NSF的法定使命，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。

The project investigates a sustainable process that uses catalytic reactions driven by solar energy to convert biomass to hydrocarbon chemicals. The process uses a new catalytic material that generates small reactive molecules that combine to form larger molecules with 10-20 carbon atoms, like those found in diesel and jet fuels. By using biorenewable feedstocks in combination with solar-driven chemical processing, the project could lay the groundwork for a near-zero greenhouse gas technology for producing fuels and high-value chemicals from biomass. The project includes a novel outreach program that educates high-school students in current science issues and provides opportunities for them to be spokespersons for conveying those issues to the broader public.Photocatalysis has recently been reported to enable room-temperature dehydrogenative C-C coupling of 2,5-dimethyl furan (2-5 DMF) and 2-methy furan (2-MF) while producing hydrogen simultaneously. However, the process suffers from low conversion and poor selectivity, as well as sensitivity to oxygen. The underpinning mechanism (i.e. the radical species generated from C-H activation of the methyl group would resonate to furan rings and lead to a variety of isomer products) is understood as a key reason for this important deficiency. Recently, one of the investigators has discovered that under photoelectrochemical conditions, Ta3N5 can enable an alternative radical-based pathway that is not only highly efficient but also insensitive to impurities such as H2O or O2 in ambient air. The project will extend those studies to photocatalytic biomass conversion. To that end, detailed understanding of the reaction mechanism is needed. The mechanistic studies will include light-dark experiments, detailed product characterization, and experimentation with various radical generator and acceptor species. Moreover, comparisons will be made between the Ta3N5 utilized as a photoelectrode and as a heterogeneous photocatalyst, with co-catalysts such as platinum included in some cases.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.