Understanding the factors that affect efficiency of manganese oxides as water oxidation catalysts is an essential step towards developing commercially viable electrocatalysts. Density functional theory calculations have been employed to investigate water oxidation processes on manganese dimer, trimer, and cubane complexes. The effect of different oxidation states of manganese has been considered.  Processes such as nucleophilic attack by solvent water molecules are implicated in many of the mechanisms.  For all systems studied, the highest energy step in the mechanism, which is responsible for the overpotential in the water splitting process, is found to be the formation of a manganese oxo group.  The formation of these manganese oxo groups can be used as a descriptor for selecting a manganese-based water splitting catalyst due to the high electrochemical potentials required for their generation.<br/>During the nanoparticle growth process, a variety of precursors are formed.  In this work, we examine both the one- and two-phase growth mechanisms for gold-thiolate nanoparticle formation.  Intermediates formed during these reactions are found to be in good agreement with those observed experimentally.  Factors such as the R group, solvent, and pH during the reaction are considered, as this affects the reaction energetics and therefore the potential growth processes.

Density functional theory investigations of water splitting mechanisms and nanoparticle growth mechanisms

2019 Spring National Meeting

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