Untangling Photoreactivity of Oxide Nanoparticles

在化学系化学结构、动力学和机理A(CSDM-A)项目的支持下，利哈伊大学的Lisa Fredin正在使用计算方法探索二氧化钛纳米颗粒的光化学和光物理性质。虽然表面结构已知对光催化剂的性质有根本的影响，但目前的大多数模型不能捕捉到真实实验系统的复杂性。特别是，纳米光催化剂被广泛使用，但需要新的模型来预测这些颗粒的角落和边缘的反应活性。弗雷丁博士和她的学生将建立系统的纳米二氧化钛模型，然后使用它们来直接探索这种具有工业重要性的材料的光物理和反应性。他们的发现可能会导致更好地理解纳米二氧化钛界面的化学和物理，并改变光催化剂模型的开发方式。此外，他们的努力可以增加STEM(科学、技术、工程和数学)劳动力的多样性和计算素养，方法是为职业生涯早期的本科生和来自代表性不足群体的学生提供身临其境的研究体验，以及专门的动手科学计算和编码工作坊。本项目侧重于光物理和纳米二氧化钛粒子的反应性的计算研究。这项拟议的工作将建立具有刻面和无定形表面的纳米结构二氧化钛的大型团簇模型。通过系统地比较各种形状的颗粒，拟议的研究有可能在运行实验之前提供如何对纳米级氧化物的光响应和反应性进行建模的更完整的理解。利用密度泛函理论(DFT)方法和大团簇模型，首次系统地计算了氧化物小平面和非晶态纳米粒子表面的光催化势垒。这项研究可能会改进光催化的第一原理模型，提供对广泛应用和反应中使用的重要材料的深入见解。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Lisa Fredin of Lehigh University is exploring the photochemical and photophysical properties of titanium dioxide nanoparticles using computational methods. While surface structure is known to have a fundamental impact on the properties of photocatalysts, most current models cannot capture the complexity of real experimental systems. In particular, nanosized photocatalysts are widely used but new models that can predict the reactivity at corners and edges of these particles are needed. Dr. Fredin and her students will build systematic nanotitania models and then use them to directly explore photophysics and reactivity of this industrially important material. Their discoveries could lead to a better understanding of the chemistry and physics of nanotitania interfaces and transform how models of photocatalysts are developed. In addition, their efforts could increase diversity and computationally literacy in the STEM (science, technology, engineering and mathematics) workforce through providing immersive research experiences for early career undergraduates and students from underrepresented groups and dedicated hands-on scientific computation and coding workshops.This project focuses on computational studies of photophysics and reactivity of nanotitania particles. The proposed work will build large cluster models of nanostructured titania with both faceted and amorphous surfaces. By systematically comparing various shaped particles, the proposed research has the potential to provide a more complete understanding of how to model the photoresponse and reactivity of nanoscale oxides before running an experiment. Using density functional theory (DFT) methods and large cluster models, this work aims to provide the first systematic calculation of photocatalytic barriers on oxide facet edges and amorphous nanoparticle surfaces. This study will likely improve first principle models of photocatalysis by providing in depth insights into important materials used in a wide variety of applications and reactions.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.