In this feature article we discuss recent advances and challenges in measuring, analyzing and interpreting
the electrostatic potential development at crystal/electrolyte interfaces. We highlight progress
toward fundamental understanding of historically difficult aspects, including point of zero potential estimation
for single faces of single crystals, the non-equilibrium pH titration hysteresis loop, and the origin
of nonlinearities in the titration response. It has been already reported that the electrostatic potential is
strongly affected by many second order type phenomena such as: surface heterogeneity, (sub)surface
transformations, charge transfer reactions, and additional potential jumps at crystal face edges and/or
Schottky barriers. Single-crystal electrode potentials seem particularly sensitive to these phenomena,
which makes interpretation of experimental observations complicated. We hope that recent theory developments
in our research group including an analytical model of titration hysteresis, a perturbative surface
potential expansion, and a new surface complexation model that incorporates charge transfer processes
will help experimental data analysis, and provide unique insights into the electrostatic response of nonpolarizable
single-crystal electrodes
