Excellence in Research: Transition metal carbides and nitrides supported single-atom catalysts for aqueous-phase methanol reforming

氢是一种清洁燃料，主要是通过高温下碳氢化合物的催化重整从化石资源中产生的。或者，它可以通过简单醇如甲醇的水相重整在低温下更有效地生产。该项目探索了甲醇（一种可再生原料）制氢的可行性，并通过设计在低温液体环境中有效工作的新型催化剂来促进。同时，该项目为一个多学科研究项目奠定了基础，为计算科学领域代表性不足的非洲裔美国学生提供研究和教育机会，同时更广泛地加强了佛罗里达农业机械大学（FAMU）的研究能力，这是一所历史悠久的黑人学院和大学（HBCU）。本研究对低成本过渡金属碳化物（TMCs）和氮化物（TMNs）负载的单原子催化剂（SACs）上甲醇水相重整（APRM）进行了计算和实验相结合的研究。SACs是一种新兴的材料，它提供接近100%的金属利用率，并具有均相和非均相催化剂的综合优势。理论计算将通过实验测量验证，以揭示过渡金属碳化物和氮化物（tmc和TMNs）负载的Pt， Pd， Rh和Ni SACs的稳定性和构效关系。该项目包括三个目标：1)通过密度泛函理论（DFT）计算、机器学习（ML）方法和超高真空扫描隧道显微镜/光谱（STM/STS）测量，研究沉积在各种tmc和TMNs上的SACs的稳定性和电子结构；2)通过DFT模拟原位和非原位STM识别的催化剂结构与反应能量的关系，确定APRM在稳定sac上的活性位点和反应机理；3)应用动力学蒙特卡罗（KMC）模拟和气液间歇反应器实验结果，确定有前途的SAC候选APRM。从这个项目中获得的对SAC结构组成和稳定性的原子性理解，以及对APRM的机理认识，有望转移到其他SAC构型和其他醇重整反应中。除了技术方面，该项目还涉及教育和推广活动，重点关注从K-12到研究生的少数民族和代表性不足的群体，并涉及学生与当地高中、塔拉哈西社区学院和FAMU附属发展研究学院的互动。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。

Hydrogen, a clean fuel, is primarily produced from fossil resources via the catalytic reforming of hydrocarbons at high temperatures. Alternatively, it can be produced more efficiently at low temperature through the aqueous-phase reforming of simple alcohols such as methanol. The project explores the feasibility of hydrogen generation from methanol (a renewable feedstock) as facilitated by novel catalysts designed to work efficiently at low temperatures in liquid environments. Concomitantly, the project lays the groundwork for a multidisciplinary research program providing research and education opportunities for underrepresented African American students in the area of computational sciences, while more broadly strengthening the research capability of Florida Agricultural and Mechanical University (FAMU), a historically black college and university (HBCU).The study involves a combined computational and experimental study of aqueous-phase reforming of methanol (APRM) on single-atom catalysts (SACs) supported on low-cost transition metal carbides (TMCs) and nitrides (TMNs). SACs are an emerging class of materials that offer near 100% metal utilization and possess the combined advantages of homogeneous and heterogeneous catalysts. Theoretical calculations will be validated with experimental measurements to unravel the stability and structure-activity relationships of Pt, Pd, Rh, and Ni SACs supported on transition metal carbides and nitrides (TMCs and TMNs). The project embraces three objectives: 1) investigation of stability and electronic structure of SACs deposited on various TMCs and TMNs via density functional theory (DFT) calculations, machine learning (ML) methods, and scanning tunneling microscopy/spectroscopy (STM/STS) measurements in ultrahigh vacuum; 2) identification of active sites and reaction mechanisms of APRM on stable SACs through DFT simulations of reaction energetics associated with catalyst structures identified by in-situ and ex-situ STM; and 3) application of Kinetic Monte Carlo (KMC) simulations and results of gas-liquid batch reactor experiments to identify promising SAC candidates for APRM. The atomistic understanding of structure compositions and stability of SACs, as well as the mechanistic insight of APRM obtained from this project, is expected to be transferable to other SAC configurations and other alcohol reforming reactions. Beyond the technical aspects, the project involves educational and outreach activities focused on minorities and underrepresented groups ranging from K-12 through graduate students, and involving student interactions with local high-schools, Tallahassee Community College, and the FAMU affiliated Developmental Research School.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.