Interface Engineering of ZIF-67 derived Heterostructured CeO2@Co3O4 Polyhedron Promoted by Reduced Graphene Oxide for Enhanced Oxygen Evolution Reaction

Owing to decrease the energy consumption for water-splitting at large-scale and to expedite the slower kinetics, the construction of heterostructure towards the formation of a highly effective and dynamic electrocatalyst for oxygen evolution reaction (OER) is a vital requirement. Cobalt oxide-based electrocatalysts with conductive supporting material have shown promising electrochemical properties and are well-known to be remarkably effective in various energy applications. In the present work, we developed a heterostructure of reduced graphene oxide (rGO) promoted and CeO2 introduced polyhedral Co3O4 derived from Zeolitic-imidazolate framework-67 (ZIF-67) template (CeO2@Co3O4/rGO-2) via simple in-situ growth synthesis approach followed by pyrolysis-calcination strategy. The as-prepared CeO2@Co3O4/rGO-2 electrocatalyst displayed an outstanding improvement in the electrocatalytic performance due to the robust electron interaction amongst CeO2@Co3O4/rGO-2, which offers extraordinary interfacial electron transfer, strong synergistic interaction that is endowed with a large number of active sites and oxygen vacancy generation caused by the influence of CeO2. The CeO2@Co3O4/rGO-2 electrocatalyst reveals a much lower onset potential of ∼1.42 V vs. RHE and a smaller Tafel slope of 32 mV/dec under an alkaline environment for OER. The CeO2@Co3O4/rGO-2 electrocatalyst demonstrates a good electrochemical stability performance in 1.0 M KOH. These achieved outcomes deliver a worthy approach for developing an electrocatalysts derived from cobalt-based MOF to facilitate water splitting as well as other energy applications.