Electrodeposited graphene@Co3O4 nanosheets for oxygen evolution reaction

With the increasing demand for renewable and clean energy, highly efficient and low-cost electrocatalysts for oxygen evolution reaction (OER) have attracted great interest in the field of hydrogen energy. In this work, we report a novel strategy to prepare graphene (Gr, rather than graphene oxide)-supported highly efficient catalyst for OER. Gr-supported Co3O4 free-standing nanosheets (Gr@eCo3O4) are fabricated by electrodeposition. SiO2 is used as a template for co-electrodeposition, and is further etched by alkali. Gr provides large electrochemical surface area and abundant catalytically active sites, as well as enhances the conductivity of Co3O4. Meanwhile, the charge transfer kinetics of OER is improved on Co3O4 electrodeposited on Gr. Gr@eCo3O4 exhibits superior OER performance with a Tafel slope of 45 mV dec−1 at 10 mA cm−2. [Display omitted] •Electrodeposition of Gr@eCo3O4 nanosheets with SiO2 as a template.•Co3O4 is tightly bonded to Gr and the size of Co3O4 is small.•Electrons interaction and charge transfer in Gr@eCo3O4 nanosheets.•Electrodeposited Gr@eCo3O4 nanosheets exhibit highly efficient catalytic activity.