Two flowers per seed: Derivatives of CoG@F127/GO with enhanced catalytic performance of overall water splitting

In this work, cobalt glycerate ([email protected]) nanosheets grown on the surface of graphene oxide (GO), i.e. [email protected]/GO, have been synthesized with the assistance of nonionic surfactant Pluronic F127 via a hydrothermal method. After calcination, [email protected]/GO is transformed into one derivative, Co nanoparticles coated with a trace amount of carbon (Co-C) on GO (Co-C/GO). The Co nanoparticles consist of an atypical core–shell structure, in which the core and the shell are both Co. Co-C anchored on GO can avoid the nanoparticles aggregation and expose more active sites for hydrogen evolution reaction (HER) to significantly improve the catalyst activity of HER. [email protected]/GO is phosphatized to form the other derivate, cobalt pyrophosphate coated with a small amount of carbon (Co2P2O7-C) on GO (Co2P2O7-C/GO). Co2P2O7-C/GO composite owns a large electrochemical active surface area (ECSA) and fast rate towards oxygen evolution reaction (OER). Furthermore, the two derivatives of [email protected]/GO, i.e. Co-C/GO and Co2P2O7-C/GO as twin flowers, are assembled into an overall water splitting electrolytic cell with a cell voltage of 1.56 V to deliver a current density of 10 mA cm−2.