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: Fatih Sen Applicant's institution: ANL Applicant's division: NST Project Name: iro-catal Project title: Computational IrO2 catalyst design Associated funding: LDRD Other Systems: We have 420000 core hours at Carbon cluster at Center for Nanoscale Materials Science: Iridium oxide is one of the most efficient electrocatalysts for the oxygen evolution reaction (OER) in the water splitting process, for efficient solar energy into fuel (H2) conversion. Atomistic modeling of IrO2 is critical for understanding the structure, chemistry, and nanoscale dynamics of IrO2 in these applications. In previous studies, the size and shape of nanoclusters has been reported to have significant affect on the catalyst performance as a result of change in the local atomic coordination at the nanocluster surfaces, edges and corners. These studies however, are mostly focused on metallic nanoclusters, but the atomistic mechanisms of catalytic activity change with size and shape of oxide nanoclusters are yet to be determined. We have previously developed a first principles based Morse + QEq (MS-Q) variable charge force field for this technologically important Ir-O system that can predict the catalytic activity and structural stability of IrO2 nanoclusters in water splitting and OER. In this project, we will carry out molecular dynamics calculations using the MS-Q to reveal the shape and size affects on the catalytic activity of IrO2 nanoclusters. DFT calculations will be simultaneously performed to estimate the surface and nanocluster stability for selected systems for comparison. Project description: The DFT calculations on IrO2 surfaces and selected nanoclusters will be carried out using the plane wave code VASP available in both Fusion and Blues. The PBE exchange correlation and Hubbard U correction, as well as the projector augmented wave (PAW) method, will be used. All calculations will be carried out including spin polarization and spin orbit coupling. Classically molecular dynamics calculations will be carried out using the GULP software with the previously developed MS-Q force field. The details of the calculations can be listed as: i) DFT calculations will be carried out to study surface stability and catalytic activity of water splitting reaction and OER on IrO2 surfaces. We identified 20 different surface structures and we will consider at least 3 different adsorption sites on each surface. Each of these calculations are estimated to take 30 hours on 64 cores. The total request for this part is 30 * 64 * 3 * 20 = 115, 200 core hours. ii) To evaluate the stability, and catalytic activity of iridium oxide nanoclusters, molecular dynamics (MD) simulations will be carried out for different cluster sizes and shapes. Approximately 100 MD simulations will be carried out considering all different type of clusters and adsorption sites. The time estimated for each simulation is 100 hours in 16 cores. The total request for 100 MD simulations is: 100 * 16 * 100 = 160,000 core hours. iii) For selected small nanoclusters (< 500 atoms), we will carry out five DFT calculations to predict the catalytic activity and compare with the MS-Q force field. Each large scale DFT calculation is expected to take 4 days on 256 cores, which will require a total of 4 * 24 * 256 * 5 = 122,880 core hours. Industry partnership: Project URL: Requested allocation: 400000 Q1: 0 Q2: 0 Q3: 0 Q4: 400000 Justification: Storage requirements: 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