An all-solid photoelectrochemical cell for the photooxidation of organic vapours under ultraviolet and visible light illumination

An all-solid photoelectrochemical cell has been tested in the photooxidation of methanol vapours as a proof-of-concept for the application of electrochemically enhanced photocatalysis in air treatment. The cell was based on a Nafion^®-impregnated microporous membrane that served as the solid polymer electrolyte. The working and reference electrodes (a TiO₂/WO₃-coated stainless steel mesh and AgCl-coated Ag wire, respectively) were adhered with the addition of a Nafion^® solution onto one face of the membrane, while the counter electrode (a plain stainless steel mesh) was attached to its opposite face. The use of an electrosynthesized TiO₂/WO₃ photoelectrode allowed the utilization of both UV and visible light. The device was tested by constant potential photoamperometry in air streams saturated with water or water–methanol vapours and the obtained photocurrent increased with increasing methanol levels, confirming the photoelectrochemical oxidation of methanol vapours under UV and visible light illumination.