Graphite-graphene architecture stabilizing ultrafine Co3O4 nanoparticles for superior oxygen evolution

Tremendous strides have been made in active and stable electrocatalysts of oxygen evolution reaction (OER) for water splitting to produce hydrogen. Nevertheless, the electrocatalysts with highly exposed active sites, fast electron/charge and mass transfer capabilities and long-term stability are still requisite. An efficient strategy of electrochemical activation is presented to fabricate the graphite-graphene Janus architecture and further stabilize the ultrafine Co3O4 nanoparticles for OER. The wrinkled and cross-linked graphene sheets that are in-situ formed and firmly bonded on the conductive graphite foil, act as pillared spacer for fast mass transport and anchoring sites for nucleation and growth of uniform distributed Co3O4 active species. The interlayer graphite contributes to the fast charge transfer as conductive substrate/framework. Benefitting from these merits, the resultant electrocatalyst achieves the outstanding OER performance with small overpotential (301 mV at 10 mA cm−2), low Tafel slope (47 mV dec−1) and long-term durability in basic medium.