Potential-Tunable Metal–Organic Frameworks: Electrosynthesis, Properties, and Applications for Sensing of Organic Molecules

Properties of metal–organic frameworks (MOFs) are determined by metal centers, organic ligands, and applied synthesis methods. For electrosynthesis of MOFs, the applied potential is expected to play a key role in determining the morphology, thickness, electrochemical properties, and applications of MOFs. Herein, Cu-BTC (H3BTC: 1,3,5-benzenetricarboxylic acid) films are electrosynthesized at different cathodic potentials. They feature different morphologies, thicknesses, and amounts of active copper centers, although they do show similar bonding properties, chemical compositions, phase purity, crystallinity, and surface electronic states of copper centers. Using nicotine amide adenine dinucleotide, the sensing application of these Cu-BTC films is explored, showing potential-dependent catalytic ability. Further monitoring of six other organic compounds (herein xanthine, hypoxanthine, diethylstilbestrol, estradiol, sunset yellow, and tartrazine) reveals the morphology and thickness of Cu-BTC films and the amount of copper centers inside these Cu-BTC films determines the accumulation or sensing ability of Cu-BTC films. Highly sensitive detection of these molecules individually and simultaneously is achieved with Cu-BTC electrosynthesized at −1.30 V. Electrosynthesized Cu-BTC films are thus excellent electrode materials for sensitive sensing of various analytes.