In the simplest version, a photoelectrochemical (PEC) cell consists of a semiconducting light absorber and an electrolyte solution. The functions of the light absorber include photon absorption, as well as charge generation, separation, and transport towards the liquid/solid interface (i.e. electrolyte/semiconductor). The liquid electrolyte is a concentrated solution that provides the reactant (e.g. water), and connects electrically the anodic and cathodic reaction sites by enabling ionic transport. Typically, liquid electrolytes are strongly acidic or basic in order to improve the ionic conductivity and to decrease polarization losses. However, these conditions create an aggressive environment, which can have an adverse effect on the stability of the photoactive material.^1,2