Structural Transition in the Growth of Copper Terephthalate Metal–Organic Frameworks: Understanding the Effect of the Synthetic Protocol and Its Impact on Electrochemical Behavior

SARA L. RODRÍGUEZ; ORTEGA-MORENO GABRIELA; MANUEL SÁNCHEZ-SÁNCHEZ; JOSE LUIS FERNÁNDEZ; J.M. ZAMARO

Coatings

MDPI

Lugar: Basel; Año: 2023 vol. 13

2079-6412

Some copper-based metal–organic frameworks show promise for use as electrocatalystsbecause they allow for an electrode configuration in which copper species with redox and electronconducting properties are immobilized in a three-dimensional arrangement. This work shows that the synthesis of copper terephthalates (Cu-BDCs) can lead to rigid structures of the copper hydroxyterephthalate-type or flexible structures that are isoreticular to the MOF-2 type, depending solely on the synthesis route. Here, a detailed analysis of the syntheses of the crystals is carried out employing protocols with different solvents as well as conventional or microwave-assisted solvothermal methods. All solids were fully characterized by a combination of characterization techniques, such as FE-SEM, T-XRD, TGA, and FTIR, and their electrochemical redox responses were also evaluated by cyclic voltammetry. A correlation between the Cu-BDCs structures and their electrochemical behaviors was established and a new version of an electroactive copper hydroxyterephthalate was synthesized by a microwave method in 3 h with a dimethylformamide-free protocol. This Cu-BDC was obtained as dispersed nanoflakes with a high amount of copper sites and the capacity to be reversibly electroreduced-oxidized and showed catalytic activity in the oxygen reduction reaction (ORR).