Lucía Mendizabal, Antía Villamayor, Eva G-Berasategui, Tekniker, Basque Research and Technology Alliance, Eibar, Spain
The development of cost-effective components for PEM electrolyzers plays a crucial role in the transformation of renewable energy into hydrogen. To achieve this goal, it is essential to address the scarcity and high cost of platinum group metals (PGMs) used in PEM electrolysis. Reducing the quantity of these expensive materials is necessary to make PEM electrolysis a more affordable technology without compromising cell performance. Platinum is the most active catalyst for driving hydrogen evolution reaction (HER) and it has been proved that is possible to reduce its amount without reducing the cell efficiency. Taking this into account, it is important to find a robust automated industrial manufacturing process that not only reduces the amount of platinum required but also avoids the waste of catalyst. The most commonly used method for developing Pt HER (hydrogen evolution reaction) electrodes involves mixing Pt nanoparticles with carbon black powder using wet chemical impregnation which results in high surface area catalysts. However, chemical synthetic approaches have several drawbacks, such as complex reaction pathways, the formation of byproducts, and challenges in scaling up for industrial production.
To address these issues, physical vapor deposition (PVD) techniques, specifically magnetron sputtering, offer a promising solution. Magnetron sputtering allows the production of highly pure thin films in a single-step process without generating any unwanted byproducts. Additionally, magnetron sputtering is a well-established industrial and automated technique for thin film deposition, making it an attractive alternative for manufacturing PEM catalytic materials on a large industrial scale.
This research work has two main objectives to solve the aforementioned issues. First, the development of three ultralow loading Pt electrodes for HER to confirm that reducing the amount of catalyst does not negatively affect the catalytic activity. And second, to do so using an industrial technique like magnetron sputtering, enabling the possibility of electrode fabrication in an automated one-step process diminishing the waste of Pt without producing byproducts.
Three types of nanoparticled electrodes with ultralow platinum loading 0.1, 0.066, and 0.052 mg/cm² were developed through magnetron sputtering. The electrodes showed remarkable overpotentials as low as 8 mV at 10 mA/cm² for the hydrogen evolution reaction (HER), proving that the performance of the electrodes remained as good as, or even better than the commercial electrodes while using at least four times less platinum (0.3 mg/cm² Pt/C commercial electrode).