2024

Givirovskaia Daria; Givirovskiy Georgy; Laitinen Ville; Park Yuri; Amin Parsa; Rehman Aafaq; Rezaei Nima; Repo Eveliina

Metal-organic frameworks (MOFs), with their highly coordinated structure, high porosity, and tunability have piqued vast scientific attention as a promising platform for creating high-efficiency electrocatalysts for water electrolysis. However, the conventional methods of creating MOF-derived electrocatalysts are time- and energy-consuming and often lead to significant aggregation of metal particles and the formation of non-homogeneous porous structures. In this research, we leverage the potential of the MOF-template-directed fabrication approach, combined with microwave heating and laser-assisted post-treatment, to develop a facile, scalable, and versatile strategy for electrocatalyst synthesis. Specifically, hierarchically structured Ni-based MOF-74 was rapidly synthesized from the Ni hydroxide nanosheet arrays deposited onto a Ni foam substrate using microwave-assisted synthesis. Subsequently, the obtained structures were treated using a focused laser to create MOF-74(Ni)-derived composite electrocatalyst featuring encapsulated nickel oxide nanoparticles. The resulting electrocatalyst exhibited high efficiency and stability for facilitating the oxygen evolution reaction (OER) under alkaline conditions. The outstanding electrocatalytic performance of the developed material enables it to reach a current density of 50 mA cm-2 at an overpotential of 318 mV. High electrocatalytic activity can be attributed to its distinctive morphology, which offers numerous exposed active sites for water splitting. The experimental data gathered in this study is anticipated to be of significant value for the synthesis of other MOF-derived composite materials featuring hierarchical structures. Furthermore, the study emphasized the importance of using a combination of microwave heating and laser-assisted post-treatment of MOFs to achieve a sustainable and efficient process for electrocatalyst synthesis.