Research Highlights

Chemistry of complex materials: e-Nanochemistry & multiscale modelling

Authors: Dou Du, J. Kullgren, K. Hermansson and P. Broqvist (UU)

Experimental  studies have reported a dramatically increased oxygen storage capacity (OSC) for small ceria nanoparticles (∼5 nm). Both experiments and theory have correlated this effect with superoxide ion formation. Here from hybrid DFT calculations, extrapolated to force-fields involving large nanoparticles (3−10 nm), in conjunction with first-order desorption kinetics, we find that superoxide ions are indeed stable on nanosized ceria well above room temperature, in accordance with experiments.

From Ceria Clusters to Nanoparticles: Superoxides and Supercharging

Frontiers in Chemistry 7, article id 203, (May 2019)9

Chemistry of complex materials: Designing a high-dimensional NN potential gives maximally resolved vibrational spectra

Authors:  Vanessa Quaranta, Matti Hellström, Jörg Behler, Jolla Kullgren, Pavlin D. Mitev, and Kersti Hermansson

Unraveling the atomistic details of solid/liquid interfaces, e.g., by means of vibrational spectroscopy, is of vital importance in numerous applications, from electrochemistry to heterogeneous catalysis. A reactive high-dimensional neural network potential based on density functional theory calculations was developed and  then used to sample the interfacial structures by means of Molecular dynamics simulations. In the second step, one-dimensional potential energy curves have been generated for a very large number of configurations to solve the nuclear Schrödinger equation. Finally, we have been able to identify substantial correlations between the stretching frequencies and hydrogen bond lengths for all species.

J. Chem. Phys. 148, 241720 (2019);

Chemistry of complex materials: Tailoring energy materials for efficient Hydrogen Evolution Reaction

Authors: Giane Benvinda Damas, Cleber Fabiano N. Marchiori, and Carlos Moyses Araujo

Polymeric materials containing an extended π-conjugated backbone have shown a wide range of applicability including photocatalytic activity for hydrogen evolution reaction (HER). The latter requires highly efficient materials with optimal light absorption and thermodynamic driving force for charge transfer processes, properties that are tailored by linking chemical units with distinct electron-affinity to form donor-acceptor architecture. Here, this concept is explored by means of ab initio theory. Our findings reveal that the donor unit plays a crucial role on key properties that govern the photocatalytic activity of donor-acceptor polymers contributing to the development of a practical guideline to design more efficient photocatalysts for HER.

J. Phys. Chem. C, 2019, 123, 42, 25531-25542