Photocatalytic properties of Co/Co3O4 films recycled from spent Li-ion batteries

• Published in: Ionics 2018-07, Vol.24 (7), p.2167-2173
• Main Authors: Falqueto, J. B., Magnago, L. B., Rocha, A. K. S., Pegoretti, V. C. B., Dixini, P. V. M., Celante, V. G., Lelis, M. F. F., Freitas, M. B. J. G.
• Format: Article
• Language: English
• Subjects: Azo dyes; Banded structure; Catalysis; Charge density; Chemistry; Chemistry and Materials Science; Cobalt oxides; Condensed Matter Physics; Degradation; Discoloration; Electrochemistry; Energy Storage; Hydrogen peroxide; In situ leaching; Leaching; Lithium-ion batteries; Optical and Electronic Materials; Reaction kinetics; Rechargeable batteries; Renewable and Green Energy; Short Communication; Ultraviolet radiation
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-018-2614-3

Cobalt recycled from spent Li-ion batteries has been used in the catalysis of azo dye. Metallic cobalt with a compact hexagonal structure was recycled by electrodeposition after leaching a solution of Li-ion battery cathode and applying a potential of − 1.1 V, with charge density = 15 C cm −2 and pH = 2.7. This cobalt, with H 2 O 2 0.27 mol L −1 , was used for degradation of azo dye. H 2 O 2 transformed Co in situ into Co 3 O 4 with a spinel-type structure. Co 3 O 4 was confirmed by Raman spectrum bands in the region of 450 and 700 cm −1 . The kinetics of the degradation reactions are of first order. Discoloration efficiency of 85% was reached after 210 min under UV radiation. Formation of Co 3 O 4 in situ is an innovative and efficient method to solve two problems: Li-ion battery recycling and azo dye discolorization.