Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Ujjal Das Project Name: 1atomCat Division: MSD Project title: Supported Single-Site Catalysts for Activation of Small Molecules Associated funding: BES Chemical Sciences Other Systems: CNM Carbon cluster - 100,000 cpu hrs. Science: This proposal requests a renewal of our previous proposal titled "Supported Single-Atom Catalysts for Activation of Small Molecules" but into new directions. Over the last two years, we have primarily focused on understanding the structures of catalyst active sites, exploring various reaction pathways, building structure-function relationships, and used them to screen and predict new materials with improved activity and selectivity. The entire efforts remained within the framework of single atom catalysts consisting of elements from first-row transition (Fe, Co) and post-transition (Zn, Ga) metals. While these catalysts show excellent selectivity for propane dehydrogenation to propylene, the activity is moderate-to-low, especially in comparison with some of the state-of-the-art alkane dehydrogenation catalysts. In the current proposal, we propose to develop supported single atom catalysts consisting of late transition metals (LTM) such as Pd, Pt, Rh etc, as they are known to be highly active for activation of small molecules such as H2 and alkanes. However, these elements are difficult to stabilize as isolated atom on typical oxide support materials (SiO2, Al2O3) because of weak metal-support interaction energy. As a result, they tend to agglomerate and form larger nanoparticles even at a moderate temperature. Since many of our target chemical reactions, such as dehydrogenation of alkane, require high temperature, synthesizing stable single atom LTM catalysts in this condition is a major challenge. Recently, it has been shown that metal-support interaction energy, especially for LTM, depends strongly on the size of the support materials. For example, while a few atom platinum clusters (Pt8) are not stable on typical cerium oxide surfaces, they can be stabilized on ceria particles of a few nanometers. Since, some of our experimental colleagues have strong expertise in growing materials using atomic layer deposition (ALD) technique, we want to explore computationally how layer thickness of support metal oxide affects the metal-support interaction energy with the ultimate goal of selecting right combination of LTM and metal oxide. Project description: To begin with, we will select typical transition metal oxides such as CeO2, TiO2, MnO2 and evaluate interaction energy of single atom LTM such as Pt and Pd with these supports as a function of layer thickness of the support oxides. The diffusion energy barriers of metal atom between different surface sites will be also computed. We will perform density functional theory (DFT) calculations to determine structure, bonding, and reaction energies of the system. Periodic boundary condition (PBC) will be imposed in order to maintain periodicity of the solid support. Gradient corrected PBE density functional will be used for these calculations. The Nudged Elastic Band (NEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers for formation of different surface species. Surface phonons will be calculated for accurate estimation of reaction free energies. We will primarily use the DFT code implemented in VASP (for periodic calculations) and Gaussian package. Both VASP and Gaussian run in parallel mode. For the MPI version of VASP, increased efficiency is observed up to 32 processors. The Linda version of Gaussian scales up to 32 processors. Energy optimization in VASP takes approximately 750 CPU hours and we plan roughly 200 of such calculations. Hessian (second order energy derivative) evaluation takes roughly 1600 CPU hours and we plan to run 50 of these calculations. Optimization and Hessian evaluation using Gaussian program take approximately the same time for model clusters. We estimate that we will have to run a total of 300 Gaussian calculations, each taking 400 CPU hours. So our total request is 350,000 core hours. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 400000 Q1: 100000 Q2: 100000 Q3: 100000 Q4: 100000 Justification: Storage requirements: Default amount Thank You, The LCRC Accounts System