Flash synthesis for conformal monolithic coatings of the Zr-based metal-organic framework (UiO-66-NH2) on non-modified surfaces: Applications in thin-film electrode systems

Abstract

Synthesis of conformal coatings of MOFs, especially water stable ones, on different surfaces is of paramount interest due to their potential applications including electrocatalysis, sensing, and separation. Despite previous efforts that resulted in successful deposition of thin-films of MOFs on flat surfaces, a rapid, low cost, and atom-efficient synthesis of such thin-films is still challenging. Herein we report a flash synthesis to produce conformal coatings of the water-stable UiO-66-NH2 on different flat or patterned surfaces, including Si and Au-coated Si wafers, glass slides, TLC silica plates, carbon-coated and FTO-coated electrodes. The flash synthesis presented herein is accomplished within ten minutes reaction time, utilizing minimal amounts of solvent and reagents, and thus is a greener synthesis to attain conformal coatings of such MOF on solid surfaces. The versatility of the approach is demonstrated by successful conformal coatings of the UiO-66-NH2 on Si, Au, glass, silica, as well as carbon surfaces, all achieved through drop-casting on the respective substrate at 100 °C for 10 min. The utility of such thin layer coating of microporous solids in supercapacitor applications, thin layer chromatography, as well as detection of heavy metal ions in aqueous solutions is also demonstrated.