Fabrication of a highly active β-PbO2-Co3O4 electrode for zinc electrowinning by pulse electrodeposition: Characterization and catalytic performance analysis

Abstract

High oxygen evolution overpotential and low corrosion resistance are regarded as the main drawbacks of anode materials in zinc electrowinning. To improve the electrocatalytic activity of oxygen evolution reactions (OER) and reduce energy consumption in zinc electrowinning, a Co3O4 nanoparticle-modified PbO2 anode was prepared on a Ti substrate with Sn-SbOX as an interlayer through pulse electrodeposition. The surface morphology, phase composition, and electrochemical properties of the as-prepared anode were systematically investigated. The introduction of Co3O4 nanoparticles refined the crystal size of PbO2 and increased the surface roughness of the anode. Electrochemical tests suggested the excellent electrocatalytic activity of the Co3O4 nanoparticle-modified PbO2 anode. Density functional theory (DFT) calculations revealed that Co3O4 nanoparticles reduced the OER free energy (1.58 eV) and that pulse electrodeposition reduced the PbO2 crystal size and increased the active surface area of the anode. In the simulated zinc electrowinning test, an improved current efficiency (90.6 %) was achieved, and the low energy consumption (2,508.29 kW·h) for zinc production per ton was significantly reduced as compared with that for the conventional Pb-0.75 %Ag anode. The lifetime of the modified electrode is increased by approximately 36.8 %. This provides a reference for the design and development of anode materials with high oxygen evolution activity and strong corrosion resistance in zinc electrowinning systems.