We present a detailed theoretical study of [Ni(PR2NR′2)2]2+ electrocatalysts for H2 oxidation and H2 formation developed at the EFRC Center for Molecular Electrocatalysis at PNNL. PR2NR′2 denotes cyclic diphosphine ligands that incorporate an amine base in each ligand chelate ring. Density functional theory-based calculations and hybrid QM/MM molecular dynamics simulations have been employed to efficiently map the complex chemistry of these catalysts. Results are rationalized in terms of the P and N substituents and their capability to tune the pKa of the pendant amines and the hydricity of the metal center. A detailed analysis of the conformational dynamics of the reaction intermediates and their role on the catalytic activity is also presented, along with a discussion on the role of solvent (acetonitrile) and of small amounts of water, which have been shown to have a dramatic effect on rates of H2 production.
ASJC Scopus subject areas
- Chemical Engineering(all)