[LCRC Accounts] Project Request: 1atomCat
Hello, A new project on the LCRC cluster has been requested. Please forward the information on to the LCRC Allocation sub-committee. Applicant's name: Ujjal Das Applicant's institution: ANL Applicant's division: MSD Project Name: 1atomCat Project title: Supported Single-atom Catalysts for Activation of Small Molecules, including Alkanes Associated funding: BES Chemical Sciences Other Systems: NA Science: Supported single-atom catalysts show exceptionally high catalytic activity compared to metal surfaces and sub-nanometer metal clusters. This high activity is attributed to large surface area of an isolated atom as well as its low coordination number. Standard techniques have been devised to prepare thermally stable single-atom catalysts using atomic layer deposition (ALD). In brief, supported single-atom catalysts show potential to activate very difficult bonds, including the ones in alkanes, with very high turn-over frequency. However, very little is known about background working principle of such single-atom catalysts. For example, how the nature of bonding of the single-atom affects its catalytic activity, how local charge density varies for different single-atom types, the role of a support, and an atomic level understanding of the mechanism of activation of small molecules. All these information are useful to control the activity and selectivi ty of the catalyst as well as to establish a structure-function relationship to understand the way such catalysts work. We plan to obtain all these information using high-level quantum chemical calculations. Project description: 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. B3LYP hybrid functionals will be used in general, however, we may also switch to gradient corrected density functionals (GGA), where, B3LYP is either very expensive or not applicable. The Nudged Elastic Band (NEB) method of Henkelman and coworkers will be used to calculate transition states and activation barriers. Surface phonons will be calculated for accurate estimation of reaction free energies. Bader charge analysis and NBO population analysis will be performed to obtain information about local charge density and orbital electron density of the single-atom catalyst. We will primarily use the DFT code implemented in Vienna Ab-initio Simulation Package (VASP-version 5 or later). We will also use Gaussian-09 program to run calculations using small clusters. The NBO program for population analysis comes with Gaussian by default. Bader charge analysis will be done using the principles of atoms-in-molecules (AIM2000). Phonon analysis will be performed using "PHONON" program which is free and can be installed locally. Both VASP and Gaussian run in parallel. MPI version of VASP and Linda version of Gaussian will be used. For VASP-MPI calculations, increased efficiency is observed up to 32 processors, whereas, Gaussian-Linda version scales up to 64 processors. Rest of the programs only run in serials. Energy optimization in VASP takes approximately 750 CPU hours and we plan roughly 100 of such calculations. Hessian (second order energy derivative) evaluation takes roughly 1500 CPU hours and we plan to run 30 of these calculations. Optimization and Hessian evaluation using Gaussian take approximately same time for model clusters. We estimate to run a total of 100 calculations, each taking 400 CPU hours. The resources will be used primarily by Dr. Ujjal Das and the PI of the project is Dr. Larry Curtiss ([email protected]). We will notify if new member joins this project or when additional resources are required. Total Request: 160,000 core hours in the remainder of the FY (till Sept 30) Project URL: Requested allocation: 160000 Q1: 0 Q2: 0 Q3: 40000 Q4: 120000 Justification: The requester has used undetermined amount hours of their initial startup project. In addition to approving an initial amount, please specify a Category and Subcategory for this project. For a list of the current selection of approved categories, please see: https://wiki.lcrc.anl.gov/wiki/Processes/Categories Once the Allocation committee has approved the project, please go to the Project Management page to create it: https://accounts.lcrc.anl.gov/projects.php Thank You, The LCRC Accounts System
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