Improvement on efficiencies of dilute alkaline water electrolyzer using membranes

For production of hydrogen, nearly 100% current efficiency and about 50% energy efficiency have been achieved by using PVA-AAc and PVA-AAc-AAm membranes. FTIR analyses of fresh and used membranes as well as AAS analyses of anolyte and catholyte confirm that membranes prevent transportation of Fe ions from anode to cathode resulting in better current and energy efficiencies for production of hydrogen and oxygen. PVA-AAm membrane has been found to be unsuitable as AAm reacts and decomposes to AAc during electrolysis in dilute KOH solution. The ratios of production rates of hydrogen to oxygen reach the steady state value of 2 in 2 h which confirms the consumption of oxygen by undesired reactions at initial stages.