A method and apparatus for the generation and collection of an aqueous peracid solution at the cathode of a PEM electrolyzer. The electrochemical process introduces carboxylic acid (such as distilled table vinegar, lactic acid, citric acid or combinations) to the anode and a source of oxygen to the cathode. The PEM electrolyzer has a gas diffusion cathode having a cathodic electrocatalyst that is capable of hydrogen peroxide generation. The peracid solution is generated at the gas diffusion cathode and the solution is very pure and may be used for disinfecting or sterilizing various items or solutions. In a second embodiment, the carboxylic acid may be provided directly to the cathode, such as in the form of an acid vapor.