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

Abstract

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.