All-carbon 3D-structured electrodes by direct ink writing as electrocatalyst supports for alkaline freshwater and...

Water splitting is a key technology for green hydrogen production, yet important challenges persist, particularly as large-scale expansion is expected, with seawater electrolysis emerging as a promising alternative to mitigate freshwater limitations. Among these challenges, the development of active, selective, and long-term stable electrocatalysts is crucial. The design of the catalyst support plays a pivotal role, and three-dimensional (3D) supports offer unique opportunities to enhance performance and optimize electrochemical reactor configurations. In this study, we demonstrate the use of 3D-structured all-carbon electrodes by Direct Ink Writing (DIW) as versatile supports for electrocatalyst preparation. NiCo-CeO₂/3D-Gr and NiFe/3D-Gr were synthesized by electrodeposition and employed as hydrogen evolution reaction and oxygen evolution reaction catalysts, respectively. Both electrodes exhibited excellent electrocatalytic behavior in alkaline and alkaline-saline media. Overall water splitting was conducted at 100 mA cm^-2 for 200 h, achieving voltages below 2 V and exceptional stability. This work highlights the potential of 3D-structured all-carbon electrodes by DIW as a platform for advanced electrocatalyst development, offering tunable architectures and a pathway for future optimization.