Tailoring electron transfer with Ce integration in ultrathin Co(OH)2 nanosheets by fast microwave for oxygen evolution reaction

Abstract The intrinsic activity of Co(OH)2 for oxygen evolution reaction (OER) may be elaborately improved through the suitable valence adjustment. Ce modification at electronic level is proved to be an efficient strategy owing to the flexible transformation of Ce3+/Ce4+. Herein, Ce0.21@Co(OH)2 with the optimized Ce doping have been fabricated to tailor the fast electron transfer for the enhanced activity and stability for OER. Firstly, the obtained core–shell structure composed of vertical loose Co(OH)2 sheets not only exposes a large number of active sites, but also provides channels for Ce doping. Secondly, the high pressure microwave with instantaneous heating can fast introduce Ce into Co(OH)2, obtaining Cex@Co(OH)2 with well dispersion and close integration. The intimated interaction between Ce and Co species may provide the “d–f electronic ladders” for accelerating electron transfer of the catalytic surface. Meanwhile, Ce promotes the formation of Co-superoxide intermediate and/or the release of oxygen, which is considered to be the rate-determining step for OER. The electrochemical measurements confirmed the low overpotential of 300 mV at 10 mA cm−2 and great stability of Ce0.21@Co(OH)2 for OER. This work demonstrates a meaningful approach to realize the tuned electronic structure through metal doping.