Mn3O4@C micro-flakes modified Ti/TiH2/-PbO2 anode for accelerating oxygen evolution reaction in zinc electrowinning

Ti-based PbO2 electrodes must currently address the high overpotential and low corrosiveness of the anodic oxygen evolution reaction (OER) during zinc electrowinning. In this study, a composite electrode composed of Ti/TiH2/beta-PbO2_Mn3O4@C (0.6 g L-1) was fabricated using Ti/TiH2 generated by electrochemical reduction of Ti/TiO2 prepared by laser ablation as an intermediate layer, co-deposited beta-PbO2, and Mn3O4@C micro-flakes prepared by high-temperature pyrolysis-oxidation as the active layer. In a zinc electrowinning test solution (50 g L-1 ZnSO4 mixed with 150 g L-1 H2SO4), the oxygen evolution and corrosion behavior of the obtained Ti/ TiH2/beta-PbO2_Mn3O4@C composite anodes were systematically investigated. Ti/TiH2/beta-PbO2_Mn3O4@C (0.6 g L-1) exhibited a low overpotential of 493 mV, a low Tafel slope of 73.6 mV dec_ 1, a low icorr of 2.320 x 10_ 5 A cm_ 2 and voltage stability of 1.65 V vs. RHE for up to 72 h in stability tests, with an overall performance outperformed most of the reported Ti-based PbO2 electrode materials. The outstanding catalytic activity is primarily attributable to the low resistance and porous interlayer of TiH2 nanosheets, which speeds up the rate of electron transfer. The addition of Mn3O4@C micro-flakes to the active layer enhances the composite electrode's OER performance and corrosion resistance.