Preparation of Nanoporous Cobalt-Iron Alloys From Samarium-Cobalt Magnet Scraps and the Performance Evaluation as the Oxygen Evolution Reaction Electrocatalysts

Samarium-cobalt (SmCo) magnets are available for critical use in aircraft, microwaves, magnetic couplings, missiles, and electrical engineering products. This work presents a new method for adeptly transforming SmCo scraps into oxygen evolution reaction (OER) catalysts, while recovering valuable elements. The SmCo scrap is directly electrochemically dealloyed in molten chloride to separate Pr, Sm, Cu, Fe, and Zr. The reaction process of SmCo scraps during dealloying is investigated by combining electrochemical techniques, ICP, XRD, and SEM-EDS. The valuable components Pr, Cu, Fe, and Zr are recovered with efficiencies exceeding 96%. The SmCo scraps formed a porous Co-Fe alloy after dealloying, and the porous alloy is found to be a candidate for OER catalysts. The relationship between dealloying parameters on the surface area and pore width of porous Co-Fe alloys is investigated. Both galvanostatic and potentiostatic methods are found to be suitable for preparing porous Co-Fe alloys with different characteristics.