  Using molecular simulation and continuum dielectric theory, we consider how
electrochemical kinetics are modulated as a function of twist angle in bilayer
graphene electrodes. By establishing an effective connection between twist
angle and the screening length of charge carriers within the electrode, we
investigate how tunable metallicity can result in modified statistics of the
electron transfer energy gap. Constant potential molecular simulations show
that the activation free energy for electron transfer is an increasing function
of the screening length, or decreasing function the density of states at the
Fermi energy in the electrode, and subsequently a non-monotonic function of
twist angle. We find the twist angle alters the density of states, which tunes
the number of thermally-accessible channels for electron transfer, as well as
the reorganization energy by altering the stability of the vertically excited
state through attenuated image charge interactions. Understanding these effects
allows us to cast the Marcus rate of interfacial electron transfer as a
function of twist angle, in a manner consistent with a growing body of
experimental observations.
