Читать книгу First virtual Bilateral Conference on Functional Materials (BiC-FM) - Сборник статей, Андрей Владимрович Быстров, Анна Владимировна Климович - Страница 10

Murdachaew G.¹, and Laasonen K.¹

1) Aalto University, Department of Chemistry and Materials Science, Finland

kari.laasonen@aalto.fi

Hydrogen obtained by electrochemical water splitting on a suitable catalyst has raised a lot of interest. The ideal catalyst should be efficient, stable under operating conditions, and composed of earth-abundant elements. Density functional theory simulations within a simple thermodynamic model of the more difficult half-reaction, the anodic oxygen evolution reaction (OER), with a single-walled carbon nanotube as a catalyst, showed that the presence of < 1 % nitrogen reduces the required OER overpotential significantly. We performed an extensive exploration of systems and active sites with various nitrogen functionalities [1] (graphitic, pyridinic, or pyrrolic) obtained by introducing nitrogen and simple lattice defects (atomic substitutions, vacancies, or Stone-Wales rotations). The lowest predicted overpotentials were about 0.4 V, close to what has been measured experimentally for the best-performing nitrogen-doped nanocarbon catalysts. The lowest predicted overpotential of 0.39 V was obtained for a model system with a Stone-Wales defect in combination with pyrrolic nitrogen doping. The most OER-active sites/systems were carbon atoms in the vicinity of Stone-Wales pyrrolic nitrogen, followed by graphitic nitrogen. For the majority of the nanotube-based systems, the third step of the four-step OER mechanism, the formation of attached OOH, is the potential-determining step of the reaction. The nanotube radius and chirality effects were examined by considering OER in the limit of large radius by studying graphene as a model system. They exhibited trends similar to those of the nanotube-based systems but often with reduced reactivity due to weaker attachment of the OER intermediate molecules.

References:

[1] G. Murdachaew and K. Laasonen J. Phys. Chem. C, 2018, 122, 25882, https://doi.org/10.1021/acs.jpcc.8b08519

Kari Laasonen is a professor of physical chemistry in Aalto University (from 2010). He did his M.Sc. in University of Helsinki 1988, PhD. in 1991 in TKK (physics). Before Aalto he worked in EPFL (Lausanne), IBM Research Laboratory (Zurich), University of Pennsylvania (Philadelphia) and University of Oulu. He has specialized to computational chemistry and especially on modelling surfaces and electrochemical reactions. He has also long expertise of modelling reaction in solutions. He has published more 150 papers and these papers have been cited more than 10.000 times.