Electrospinning Ru doped Co3O 4 porous nanofibers as promising bifunctional catalysts for oxygen evolution and oxygen reduction reactions

Enhancing the catalytic activity for oxygen evolution and oxygen reduction reactions is critical for rechargeable metal-air batteries. Herein, coral-like Ru-doped cobalt oxide nanofibers are prepared by electrospinning and subsequent heat treatment, which reduce the charge transfer resistance of cobalt oxide and optimize its active sites. Moreover, the large specific surface area and rich porosity of the one-dimensional nanomaterials prepared by the electrospinning method markedly improved the catalytic activity. Under the same catalyst load, Ru-doped cobalt oxide nanofibers have an overpotential of 300 mV, which is smaller than that of ruthenium oxide. In the oxygen reduction reaction, the positive half-wave potential of Ru-doped cobalt oxide nanofibers and Pt/C is the same (0.81 V). This work combines the strategies of doping and the advantages of electrospinning nanofibers to make a breakthrough in the catalytic activity of doped cobalt oxide nanofibers, and provides a new basis for the design of one-dimensional nanofiber bifunctional catalysts.