Collaborative Research: Highly Selective Photocatalysis on TiO2 with Atomically Dispersed Active Centers

催化剂可加速化学反应生成优选的产物，并显著节省能源和资本成本。 光催化剂-那些依赖于太阳能的-提供了一条可持续制造燃料和化学品的道路，也促进了环境污染物的修复。 该项目将研究新型光催化剂设计，用于将天然气升级为更高价值的产品，并清除空气污染物中的一氧化氮。 该研究将通过广泛的教育和推广活动进行补充，主要针对K-12和本科生来自代表性不足的background.The项目招募三名研究人员的专业知识与催化剂合成，光谱表征技术和计算催化的技能，以制备和表征结构明确和原子分散的活性位点的非均相催化剂。 将评估催化剂控制光驱动反应的产物选择性和阐明相应反应机理的能力。 该项目回应了多相催化中的一个关键挑战，即传统的合成方法经常导致各种结构不明确的催化位点。这种多样性的活性位点导致反应选择性差，并阻碍阐明反应机理。 研究人员将通过在二氧化钛（一种原型光催化剂）上合成原子分散的活性中心、单核金属位点和表面氧空位来解决这些挑战。 该项目的重点是两个技术上重要的反应，甲烷氧化为甲醇和NO还原为二氮。 这项工作涉及使用先进技术（如HAADF-STEM和EXAFS）对催化剂进行表征。 操作红外，拉曼，和X-射线光谱将被用来提供深入了解的表面反应的机制。 DFT计算将进一步补充机理信息。 该项目预计将产生新的见解的因素，管理多相催化反应的反应选择性。 该小组将采取多管齐下的方法，让代表性不足的少数群体在各自的机构参与这项研究，并教育公众了解性别平等。 具体活动包括参与NSF赞助的本科生研究经验（REU）计划，这是一门针对主要申报不在科学领域的新生本科生的创新课程，参与与当地高中的外联活动，和高水平的合作，该奖项反映了NSF的法定使命，并被认为是值得支持的，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。

Catalysts accelerate chemical reactions toward preferred products with significant savings in energy and capital costs. Photocatalysts - those that rely on the sun's energy - offer a path to sustainable manufacturing of fuels and chemicals, and also facilitate remediation of environmental pollutants. The project will investigate novel photocatalyst designs for upgrading natural gas to higher-value products and clean-up of nitric oxide from air pollutants. The research will be supplemented by a broad range of educational and outreach activities aimed primarily at K-12 and undergraduate students from underrepresented backgrounds.The project enlists the expertise of three investigators with skills in catalyst synthesis, spectroscopic characterization techniques, and computational catalysis to prepare and characterize structurally well-defined and atomically-dispersed active sites on heterogeneous catalysts. The catalysts will be evaluated for their ability to control the product selectivity of photo-driven reactions and to elucidate the corresponding reaction mechanisms. This project responds to a critical challenge in heterogeneous catalysis that traditional synthesis methods often lead to a variety of catalytic sites that are structurally poorly defined. This diversity of active sites leads to poor reaction selectivity and hinders elucidation of reaction mechanisms. The researchers will address these challenges by synthesizing atomically-dispersed active centers, mononuclear metal sites and surface oxygen vacancies, on titanium dioxide, a prototypical photocatalyst. The project focuses on two technologically important reactions, the oxidation of methane to methanol and the reduction of NO to dinitrogen. The effort involves characterization of the catalysts with advanced techniques, such as HAADF-STEM and EXAFS. Operando infrared, Raman, and X-ray spectroscopies will be employed to provide insights into the mechanism of the surface reactions. DFT calculations will further complement the mechanistic information. The project is expected to generate novel insights into the factors that govern the reaction selectivity of heterogeneous catalytic reactions. The team will pursue a multi-pronged approach to engage underrepresented minorities in this research at their respective institutions and to educate the general public about photocatalysis. Specific activities include participation in the NSF-sponsored Research Experience for Undergraduates (REU) Program, an innovative course for freshmen undergraduate students whose primary declarations are not in the sciences, engagement in outreach activities with local high schools, and a collaborative effort with high-school teachers to introduce students to molecular modeling.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.