A comparison of cathodes for zero gap alkaline water electrolysers for hydrogen production

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Description/Abstract

Selected coatings on nickel or stainless steel micromeshes have been examined as electrocatalysts for hydrogen evolution in conditions mimicking those found in zero gap alkaline water electrolysers. Voltammetry in 4 M NaOH at a temperature of 333 K, shows that Pt, NiMo and RuO2 are the coatings of choice giving a superior performance particularly at higher current densities. NiMo and RuO2 coatings also give stable performance during a 10 day electrolysis in a laboratory, zero gap, alkaline water electrolysis cell with a hydroxide conducting membrane; when combined with a NiFe(OH)2 coated anode, a current density of 1 A cm−2 is achieved with a cell voltage of ∼2.1 V. Pt catalyses H2 evolution efficiently at short times of electrolysis but cells with a Pt cathode show an increase in cell voltage from 2.05 V to 2.23 V during the first two days of operation.