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

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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.