Among the various approaches to produce sustainable and clean fuels alternative to fossil fuels, splitting of water into hydrogen and oxygen using sunlight is one of the more promising. The development of industrial electrode materials focuses on low cost, high efficiency and long lifetime.
Stainless steel or Nickel based electrodes are usually employed for practical applications. However, although these show a high initial electrocatalytic activity, under long time operation they experience extensive deactivation. On the other hand, Platinum is the best know catalyst for Hydrogen production since it requires very small overpotentials and it is very stable. Since it is quite expensive, a good approach may consist in using a very thin Pt layer deposited on less noble metal electrodes. In this paper we use Ni foam electrodes functionalized with a thin Pt layer, deposited by spontaneous galvanic displacement. We show that the proposed method has several advantages compared to other deposition techniques. First, it is a simple, low cost deposition method that does not require expensive equipments. It is also scalable and, as it will be shown, it allows to obtain uniform coverage of the 3D structured Ni foam electrode.
We compare different deposition techniques and show that spontaneous galvanic displacement can be properly optimized in order to obtain very uniform Ni coverage. We show that, thanks to the high uniformity, Pt covered Ni foam electrodes exhibit superior stability upon long term stress. An experimental method is also proposed to evaluate the amount of Pt. Optimal results in terms of stability and current are obtained with 0.015 mg/cm2 of noble metal per electrode. Such a value is about one order of magnitude lower than the typical values employed in Proton Membrane Exchange electrolyzers, therefore making the proposed approach very promising for efficient hydrogen production.