On the electrochemical deposition of metal-organic frameworks

The electrochemical deposition of Metal-Organic Frameworks (MOFs) is an interesting technique to synthesise adherent, microporous layers on top of conductive substrates. The technique can be subdivided in two approaches: anodic and cathodic deposition. While the mechanism of the cathodic approach has already been well investigated, at least for MOF-5, up to now not much is known about the anodic approach. In this paper, a four-step mechanism is proposed to better understand the anodic deposition, and the same MOF used for the investigation, HKUST-1, is also deposited cathodically to compare the two approaches. This study focuses on how nucleation starts and proceeds, on the influence of the potential applied, the stresses in the growing layers, and the origin of defects like delamination and MOF detachment. The study is followed by critical considerations on the methods and on the technique, together with suggestions and guidelines to synthesise new MOF layers.