Experimentally, it is well known that the overpotentials for the oxygen evolution reaction (OER) on RuO2 and IrO2 are similar and rather low. The question is whether widespread computational electrochemistry models based on adsorption thermodynamics are capable of reproducing such observations. Making use of DFT results of revised Perdew–Burke–Ernzerhof (RPBE) and Perdew–Burke–Ernzerhof (PBE) functionals from six different codes and various types of pseudopotentials, we show that whereas IrO2 is consistently predicted to have low overpotentials, RuO2 is predicted to have large overpotentials. A new methodology based on adsorption‐energy scaling relations shows that the inaccurate prediction for RuO2 stems from its anomalous adsorption energies of oxygen/oxygenates. Including explicit water solvation and using functionals that account for van der Waals interactions such as vdW‐DF, vdW‐DF2 and optPBE‐vdW modifies appropriately the adsorption energies so that both oxides are predicted to be highly active.

Commercially available palladium acetate often contains two major impurities, whose presence can impact the overall catalytic efficacy. This systematic study provides a comparison of the differences in catalytic activity of pure palladium acetate, Pd3(OAc)6, with the two impurities: Pd3(OAc)5(NO2) and polymeric [Pd(OAc)2]n in a variety of cross-coupling reactions. The solid state (13)C NMR spectra of all three compounds in conjunction with DFT calculations confirm their reported geometries.

Many studies of heterogeneous catalysis, both experimental and computational, make use of idealized structures such as extended surfaces or regular polyhedral nanoparticles. This simplification neglects the morphological diversity in real commercial oxygen reduction reaction (ORR) catalysts used in fuel-cell cathodes. Here we introduce an approach that combines 3D nanoparticle structures obtained from high-throughput high-precision electron microscopy with density functional theory. Discrepancies between experimental observations and cuboctahedral/truncated-octahedral particles are revealed and discussed using a range of widely used descriptors, such as electron-density, d-band centers, and generalized coordination numbers. We use this new approach to determine the optimum particle size for which both detrimental surface roughness and particle shape effects are minimized.

Perspective: Explicitly correlated electronic structure theory for complex systems The Journal of Chemical Physics 146, 080901 (2017) Current research challenges in areas such as energy and bioscience have created a strong need for Density Functional Theory (DFT) calculations on metallic nanostructures of hundreds to thousands of atoms to provide understanding at the atomic level in technologically important processes such as catalysis and magnetic materials. Linear-scaling DFT methods for calculations with thousands of atoms on insulators are now reaching a level of maturity. However such methods are not applicable to metals, where the continuum of states through the chemical potential and their partial occupancies provide significant hurdles which have yet to be fully overcome. Within this perspective we outline the theory of DFT calculations on metallic systems with a focus on methods for large-scale calculations, as required for the study of metallic nanoparticles. We present early approaches for electronic energy minimization in metallic systems as well as approaches which can impose partial state occupancies from a thermal distribution without access to the electronic Hamiltonian eigenvalues, such as the classes of Fermi operator expansions and integral expansions. We then focus on the significant progress which has been made in the last decade with developments which promise to better tackle the lengthscale problem in metals. We discuss the challenges presented by each method, the likely future directions that could be followed and whether an accurate linear-scaling DFT method for metals is in sight. Published by AIP Publishing. [http://dx

State-of-the-art catalysts are often created via deposition of monolayers, sub-monolayers or nanoparticles of the catalytic material over supports, aiming to increase the surface area and decrease the loading of the catalytic material and therefore the overall cost. Here, we employ large-scale DFT calculations to simulate platinum clusters with up to 309 atoms interacting with single layer graphene supports with up to 880 carbon atoms. We compute the adsorption, cohesion and formation energies of two and three-dimensional Pt clusters interacting with the support, including dispersion interactions via a semi-empirical dispersion correction and a vdW functional. We find that three-dimensional Pt clusters are more stable than the two-dimensional when interacting with the support, and that the difference between their stabilities increases with the system size. Also, the dispersion interactions are more pronounced as we increase the nanoparticle size, being essential to a reliable description of larger systems. We observe inter-atomic expansion (contraction) on the closest (farthest) Pt facets from the graphene sheet and charge redistribution with overall charge being transferred from the platinum clusters to the support. The Pt-Pt expansion, which is related to the charge transfer in the system, correlates with the adsorption energy per Pt atom in contact with the graphene. These, and other electronic and structural observations show that the effect of the support cannot be neglected. Our study provides for the first time, to the best of our knowledge, quantitative results on the non-trivial combination of size and support effects for nanoparticles sizes which are relevant to catalyst design.