Surfactant Intercalated Mono-metallic Cobalt Hydrotalcite: Preparation, Characterization, and its Bi-functional Electrocatalytic Application

Abstract

A series of surfactants are intercalated into mono-metallic hydrotalcite type α-Co(OH)2 through ion exchange method to produce organic-cobalt hydrotalcite (HT-SDS, HT-TMA and HT-SL). The resultant material maintains its inner laminate structure with increased interlayer spacing. FT-IR spectroscopic studies and powder XRD analysis revealed the successful intercalation of SDS into the interlayers of α-cobalt hydroxides. TEM and N2 sorption studies further demonstrate the intercalation of organic surfactant in the interlayer spacing of CoHT. XPS studies indicated the presence of surface exposed cobalt in both Co2+ and Co3+ oxidation states. Furthermore, the applicability of these intercalated materials in electrocatalytic applications specifically for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline medium is explored. Among the various investigated materials, sodium dodecyl sulphate (SDS) intercalated material exhibited better performance in terms of higher catalytic current at a lower overpotential value. Moreover, the kinetic parameters associated with electrocatalysis are determined, and the mechanism behind OER and ORR is elucidated. These results clearly demonstrate the potential bi-functional utility of such layered materials for electrocatalytic applications.