Title : Performance of nanostructured Ni alloy electrodes for hydrogen and oxygen evolution reaction in water-alkaline electrolyzer
Abstract:
Incentives toward the Hydrogen Economy offer a very interesting scenario for the coming years. Considerable research efforts are focusing on the efficient and economical production of carbon-free hydrogen production processes. In this context, the development of electrolyzers producing high-purity hydrogen with high efficiency and low-cost electrode/electrocatalyst materials is of high importance. Electrode materials play a key role in affecting electrolyzer performance, and considerable efforts have been made in recent years to obtain highly efficient and inexpensive catalytic materials.
In this work, template electrosynthesis is used to fabricate Ni alloy nanowires featuring a very high surface area characterized by high electrocatalytic activity. We found that water-alkaline electrolyzers with Ni nanowires electrodes covered by different electrocatalysts have good and stable performance at room temperature as well. To obtain different alloy compositions, NWs electrodeposition bath concentration was varied by tuning the amount of different concentrations of metals in the deposition solution and by adjusting electrodeposition parameters (current density and deposition time). Ni foam (NF) and Ni sheet (NS) differently functionalized by the same electrocatalist have been used for comparison. The main results concerning the fabrication process of nickel alloy nanowires electrodes for both hydrogen and oxygen evolution reaction will be presented and the performance in alkaline conditions discussed. For each electrode, electrochemical and electrocatalytic tests aimed to establishing the performance of the electrolyzers were carried out. In addition, an innovative alkaline electrolyzer is presented based on the use of nanostructured electrodes to tests simulating real operation. The lab-scale electrochemical reactor was made by a 3D printer and the electrolysis results from the cell operated in 30% w/w KOH aqueous solution were compared with those from a conventional one employing planar electrodes and identical conditions.
Audience Take Away:
- The fabrication process of nanostructured electrodes obtained by electrochemical deposition will be explained.
- Template electrodeposition can provide several advantages for the fabrication of highly complex structures of appropriate geometry.
- Electrochemical deposition in template is a facile method for fabricating either two- or one-dimensional nanostructured materials because it allows to easily adjust the fundamental parameters controlling their final features.
- Electrochemical processes are, usually, cheap and environmental friendly and they can be easily scaled-up from lab to industrial
