Ni and Ni-Pd nanostructures electrodes for water-alkaline electrolyses

Hydrogen production by water electrolysis (WE) is a very promising technology because it is a pollution free-process specially if renewable energy are employed. Up to day, the cost of hydrogen production by WE is higher than other available technologies, making WE not competitive. Many efforts have been made to improve WE performance, through the use of electrodes made of transition metal alloys (Pt2Mo, TiPt) as a cathode or pyrochlore type oxide (Tl2RuxIr2-xO7) as an anode [1]. In the field of water-alkaline electrolyzer, the development of cheap nanoporous nickel electrodes with high electrocatalytic features is one of the potential approaches to increase the WE performance [2]., A facile method for obtaining nanostructured electrodes is template electrosynthesis. Through this method, we have fabricated electrodes formed of Ni nanowires that have a very high surface area. In a preliminary work, we have shown that alkaline electrolyzer assembled with IrO2 nanoparticles covering Ni nanowires, acting as an anode, and a Ni sheet, acting as cathode, shows very good and stable performance also at room temperature [3]. In this work, the attention was focused on the fabrication of electrodes for hydrogen evolution reaction (HER). In particular, through metal displacement deposition, we have deposited nanoparticles of Pd on Ni nanowires electrodes with the aim to enhance the electrocatalytic performance of Ni nanowires shown in Figure 1. The results on the growth and characterization of nanostructured composite electrodes will be presented and discussed. Preliminary test on the electrolyzer performances, carried out at constant current in 30% w/w aqueous solution of potassium hydroxide, will be also reported.