Nanocarbon derived from ZIF-8 as an enhanced electro-catalyst for oxygen reduction reaction

초록

Metal organic frameworks (MOFs) are one of the well-known crystalline materials. The MOFs have been applied in various fields such as gas adsorption, drug delivery, and catalysis owing to high-porosity and uniformly formed active sites on metal clusters. MOFs have also attracted considerable attention as an electro-catalyst for oxygen reduction reaction (ORR) because of its designable framework structures comprised of metal cluster and organic ligands. In this study, ZIF-8 was adopted as a precursor for constructing nanocarbon by carbonization. During carbonization, thiourea as dopant source was added to form additional N, S doped sites on the nanocarbon. Carbonization time and temperature were carefully controlled to optimize catalytic properties. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses were carried out to compare the change in physical property of prepared samples between before and after carbonization. Pore characteristics of the materials were assessed by nitrogen sorption isotherms measured at 77 K. Electrochemical properties were investigated by linear-sweep voltammetry (LSV) and cyclic voltammetry (CV) on a potentiostat using a rotating disk electrode (RDE).