Design and fabrication of a new three dimensional Co-MOF@Sponge composite for highly selective visual sensing of inorganic acid gases

Integration of metal-organic frameworks (MOFs) and functional materials is leading to the creation of new multifunctional composites which exhibit new properties that are superior to those of the individual components through the collective behavior of the functional units. This is a rapidly developing interdisciplinary research area [1, 2]. In this work a new three-dimensional Co-MOF@sponge composite has been prepared via immobilization of a novel Co-MOF on a porous melamine formaldehyde sponge (MFS). The composite has been used for visual detection of inorganic acid gases HCl, HNO3, and H2SO4. In order to obtain an effective colorimetric MOF probe, the MOF was grown as a thin layer on the porous structure of melamine formaldehyde sponge using layer-by-layer growth of the metal nodes and organic linkers. The structure of the MOF and composite has been characterized by FT-IR, PXRD, CHN, SEM, and EDX mapping techniques. The results show high performance of the Co-MOF@sponge composite for selective visual sensing of inorganic acid gases by the naked eye.