Synergistic effects in Iridium-Decorated metal oxide nanotubes as advanced anodic catalysts for sustainable lead recovery process

The study of performance and economical Iridium-derived electrocatalysts for the acidic oxygen evolution reaction (OER) is a formidable obstacle for hydrometallurgy and water splitting. The sluggish oxidation mechanism of water molecules leads to high polarization, intensifying the competitive anodic oxidation process between Pb 2+ and H 2 O, resulting in low recovery rates and high energy consumption in lead hydrometallurgy. This study presents an Ir-doped Co-based catalyst (IrCoO x @CNT) through the in-situ growth of ZIF-67 on carbon nanotubes (CNTs), followed by ion exchange and thermal oxidation to realize the preferential catalytic oxidation of water molecules. The unique composite leverages the synergistic effects between highly dispersed Ir–Co active sites and conductive CNT network, and the formed electronic structure modulation of the Ir–Co dual sites lowers the overpotential of the OER process while raising the thermodynamic barrier for Pb 2+ →Pb 4+ oxidation. The catalyst exhibits a low overpotential of 166 mV at 10 mA cm −2 (90°C) and remarkable long-term stability in 1 M Methylsulfonic acid (MSA) to achieve reducing energy consumption to 422.52 kWh t −1 (Pb) by completely suppressing PbO 2 by-product formation, further revealed the incorporation of Ir into the Co 3 O 4 lattice enhances catalytic activity and acid resistance, while the CNT framework ensures rapid electron transport and prevents nanoparticle aggregation. This study presents a scalable strategy for practical application in sustainable metal recovery and hydrogen processes. • IrCoO x @CNT was obtained by in-situ growth, ion exchange and thermal oxidation sequential process. • It demonstrates synergistic effects between Ir–Co active sites and CNT conductive network. • Incorporating Ir into the Co 3 O 4 lattice enhances catalytic activity and acid resistance. • It shows super low overpotential of 166 mV@10 mA cm −2 in acidic media (90°C) with excellent stability. •It efficiently suppress PbO 2 formation and reduces energy consumption to 422.5 kWh t −1 (Pb).