Abstract <p>Cobalt catalysts are fundamental in the chemical industry in accelerating reactions due to their resistance to oxidation and thermal stability. However, over time, they lose effectiveness and are discarded, generating environmental waste. Traditionally, the recovery of these catalysts involves methods that emit CO₂, worsening environmental problems. This study used hydrogen (H₂) as a reductant in the pyrometallurgical recovery of metallic cobalt from spent catalysts, avoiding CO₂ emissions. Different temperatures and flow rates were tested, and it was observed that sintering influences the reduction rate. The reduction process occurred in two distinct steps: first, cobalt(III) was reduced to cobalt(II), followed by reduction to metallic cobalt. The SEM–EDS, XRF, and XRD techniques confirmed the effectiveness of the process, and kinetic studies indicated that diffusion in the solid–gas layer is the main mechanism controlling the reactions. The reduction route with H₂ proved to be an efficient, simple, and applicable method for recycling exhausted mixed cobalt oxide (Co₃O₄) catalysts compared to methods proposed in the literature, as the use of H₂ avoids the emission of CO₂ during the recovery process. This aspect is relevant to growing global concerns about reducing the carbon footprint and increasing environmental sustainability.</p> Graphical Abstract <p></p>