Composite nanoarchitectonics of ZIF-67 derived CoSe2/rGO with superior charge transfer for oxygen evolution reaction

Abstract

The poor conductivity and electronic structure of transition metal chalcogenide electrocatalysts turn to be the hurdles as the appropriate successors of noble metal electrocatalysts for oxygen evolution reaction (OER). The conductivity can be adjusted by introducing graphene to construct hetero interface, in which the stacking of graphene remains a challenge. Herein, CoSe2 anchored on reduced graphene oxide (rGO) composites were prepared using zeolitic imidazolate frameworks-67 (ZIF-67) and graphene oxide (GO) as precursors. Without iR-correction, CoSe2 anchored on rGO composites with a superior OER performance just demands a low potential of 296 mV to reach the current density of 10 mA cm−2, which is lower than that of pure CoSe2 (348 mV). The interfacial interaction between CoSe2 and rGO adjusts the electronic structure of cobalt ions and optimizes the filling of eg orbital as well as the bonding strength between cobalt ions and oxygen intermediate species, ameliorating the intrinsic OER activity. Meanwhile, the employment of ZIF-67 with a three-dimensional structure alleviates the coverage of active sites caused by the accumulation of graphene, which is also responsible for the excellent OER activity.