Encapsulation of platinum nanoparticles into a series of zirconium-based metal-organic frameworks: Effect of the carrier structures on electrocatalytic performances of composites

Investigations of the effects of different carriers on electrocatalytic properties of materials are important for heterogeneous systems. Here, we describe the development of composites based on platinum nanoparticles (Pt NPs) incorporated into three Zr-based MOFs, namely, UiO-66, UiO-67 and UiO-68. Three kinds of Zr-MOFs are composed of inorganic Zr-6(mu(3)-O)(4)(3-OH)(4) bricks connected through dicarboxylic ligands of different lengths. The surface morphology and microstructure of Pt@UiO-66/67/68 hybrid materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption-desorption measurements. Hydrazine (N2H4) is chosen as probe molecule to evaluate the electrocatalytic properties of materials due to their rich oxidation process. Cyclic voltammetry (CV) and chronoamperometry (CA) have been used to investigate the electrocatalytic properties of as-fabricated sensors for electrochemical oxidation of N2H4. These studies reveal that N2H4 shows different oxidation mechanisms and electrocatalytic performances at Pt@UiO.66/67/68 modified electrodes. Under the optimal conditions, Pt@UiO-66-2 composite exhibits the best electro-oxidation properties for N2H4. These findings may induce an awareness of the effect of the MOFs carrier structures on the electrochemical performances of composites.