Magnetron-Sputtered Electrocatalysts for Enhanced Alkaline Water Electrolysis

The rapid development of the modern society has bring problems related with global energy crisis, where the growing energy demand has putting pressure or non-renewable energy sources, resulting in substantial greenhouse gas emissions. In this way, electrochemical water splitting for green hydrogen production through renewable electricity is considered to be a promising alternative way to mitigate energy scarcity and also for the decarbonization of industrial processes. Among the available water electrolysis technologies, alkaline water electrolysis stands out for its technological maturity but is hindered by its low current density1, largely attributed to the limitations of Ni-based electrodes. To address this challenge, our study focuses on optimizing the activity and stability of Ni-based electrocatalysts. We employed confocal magnetron sputtering to physically modify Ni felts with thin films of various metal alloys (i.e. NiFe, CoFe), followed by a chemical phosphorization post-treatment. The results reveal that all sputtered electrocatalysts exhibited enhanced electrochemical activity compared to pristine Ni felts for both half-reactions of water splitting, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Notably, the OER activity was significantly improved after the phosphorization step, with NiFe−P demonstrating superior performance. On the case of HER, the phosphorization process does not improve the catalysts activity. This work underscores the potential of physical vapor deposition techniques combined with chemical modifications to develop advanced electrodes for both current and emerging electrochemical conversion technologies. [1] Acc. Chem. Res. 2024, 57, 4, 558–567