Abstract: In the disclosed electrochemical cell for the production of an alkaline solution of peroxide, especially on-site production, the electrolyte is divided into an aqueous alkaline catholyte and an aqueous alkaline anolyte, and the cathode is a gas-diffusion electrode. The active material of the electrolyte side of the gas-diffusion cathode comprises a particulate catalyst support material having a surface area of about 50 to about 2000 m.sup.2 /g, and, deposited on the particles of this support material, 0.1 to 50 weight-%, based on the weight of the active layer, of gold or gold alloy particles having an average size >40 but less than about 200 .ANG.. These gold or gold alloy particles are substantially selectively catalytic for the reduction of oxygen to peroxide (e.g. HOO.sup..crclbar.). The electrolyte flow patterns are designed to avoid loss of peroxide resulting from oxidation at the anode. In the operation of the cell, a product with a hydroxyl:perhydroxyl ratio lees than 2:1 can be obtained.