electrolyze

Electrolyze is a verb meaning to subject a substance to electrolysis: to drive a chemical reaction that would not occur spontaneously by passing an electric current through it, usually with an electrolyte and electrodes. In electrolysis, an external power source pushes electrons into or out of species in an electrolyte. Cations migrate to the cathode, where reduction occurs; anions migrate to the anode, where oxidation occurs. The overall reaction decomposes the substance or causes a non-spontaneous transformation as charge is transferred.

Electrolytes are typically aqueous solutions or molten salts that contain ions. The electrodes can be inert (such as platinum or graphite) or reactive, depending on the chemical system. The products depend on the electrolyte composition and electrode potentials; overpotentials and competing reactions influence efficiency and selectivity.

Common examples include the electrolysis of water, which produces hydrogen at the cathode and oxygen at the anode; the electrolysis of molten sodium chloride, which yields sodium metal at the cathode and chlorine gas at the anode; and electrolytic metal deposition, such as copper plating or refining.

Historically, early experiments in electrolysis were performed in the early 19th century by Nicholson and Carlisle, with further theoretical development by Michael Faraday, who formulated laws linking the amount of substance transformed to the electric charge transferred. Modern processes such as the Hall–Héroult method for aluminium and various electroplating, refining, and chemical production technologies rely on controlled electrolysis.

Applications include metal refining (electrorefining), electroplating, industrial production of chlorine and caustic soda, hydrogen production, and wastewater treatment. Safety concerns include handling corrosive electrolytes, toxic or flammable gases, and high electrical energy requirements.