Simultaneous electrosynthesis of Cu-BTC and Zn-BTC metal-organic frameworks on brass

In some applications of metal-organic frameworks (MOFs) such as in separation and sensing membranes, to achieve high performance, it would be desirable to create hetero-systems combining two different MOFs. In this study, for the first time, Cu-BTC/Zn-BTC MOF films were synthesized simultaneously on a brass alloy using the electrochemical method at room temperature and in a short time. The characterization of the MOF was performed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) theory, and scanning electron microscopy (SEM). The effect of solvent, synthesis time, and voltage on Cu-BTC/Zn-BTC MOF manufacture was investigated. The ratio of water to ethanol affects crystal size and morphology. Increasing the volume percent (v/v%) of water in the solvent mixture leads to larger crystals, and in the 50 v/v% of water, a fibrous morphology was observed. Longer synthesis times resulted in denser and intergrown films. Increasing the applied potential from 1 to 10 V resulted in different morphologies and smaller crystals. The results showed that Cu-BTC/Zn-BTC MOF films were synthesized, and by adjusting the influencing parameters, the morphology, size, and product density of the substrate are tunable.