Oxygen vacancies engineering by coordinating oxygen-buffering CeO2 with CoOx nanorods as efficient bifunctional oxygen electrode electrocatalyst

CeO2 decorated CoOx rod-like hybrid, supported onto holey reduced graphene (CoOx/CeO2/RGO) composite, was fabricated via a surfactant-assisted route. Its corresponding electrocatalytic performance towards oxygen reduction/evolution reactions (ORR and OER) was systematically investigated in alkaline electrolyte. Structural, morphological and compositional studies revealed changes in electronic and surface properties when CeO2 was introduced as an oxygen buffer material. The oxygen vacancies effectively enhanced the electrocatalytic activity, while the synergistic effect of co-catalyst CeO2, CoOx active-centers, and defective graphene with many voids facilitate the charge/mass transfer, making CoOx/CeO2/RGO an efficient and stable bifunctional electrocatalyst for OER/ORR with Delta E = 0.76 V (Delta E = E-10 mA cm(-2), OER - E-1/2,E- ORR). This parameter is 70 mV and 270 mV lower than CoOx/RGO and the benchmark Pt/C, respectively. In addition, the OER/ORR bifunctionality of CoOx/CeO2/RGO composite outperforms that of Pt/C catalyst in a H-2-O-2 micro fuel cell platform. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

The study fabricated a CeO2 decorated CoOx/RGO composite via a surfactant-assisted route and found that the introduction of CeO2 and oxygen vacancies effectively enhanced the electrocatalytic activity, leading to efficient and stable bifunctional electrocatalysis in alkaline electrolyte.