Acetonitrile Transition Metal Interfaces from First Principles

Acetonitrile
is among the most commonly used nonaqueous solvents
in catalysis and electrochemistry. We study its interfaces with multiple
facets of the metals Ag, Cu, Pt, and Rh using density functional theory
calculations; the structures reported shed new light on experimental
observations and underscore the importance of solvent–solvent
interactions at high coverage. We investigate the relationship of
potential of zero charge (PZC) to metal work function, reporting results
in agreement with experimental measurements. We develop a model to
explain the effects of solvent chemisorption and orientation on the
PZC to within a mean absolute deviation of 0.08–0.12 V for
all facets studied. Our electrostatic field dependent phase diagram
agrees with spectroscopic observations and sheds new light on electrostatic
field effects. This work provides new insight into experimental observations
on acetonitrile metal interfaces and provides guidance for future
studies of acetonitrile and other nonaqueous solvent interfaces with
transition metals.