Corrosion resistance mechanism of a novel porous Ti/Sn-Sb-RuOx/β-PbO2 anode for zinc electrowinning

Highlights: • A porous β-PbO₂ electrode is prepared by adding Sn-Sb-RuO_x interlayer. • The pores with diameters ranging between 50–180 μm. • The porous β-PbO₂ electrode prepared by electrodepositing at 20 mA/cm² demonstrate good activity and high stability. • The lifetime reaches 96 h at 1 A/cm² in 1 g/L C1⁻ and 150 g/L H₂SO₄ solution. - Abstract: Sn-SbO_x, Sn-Sb-RuO_x, and β-PbO₂ coatings were successfully deposited on a titanium substrate by using the thermal deposition and electrodeposition methods, and their electrochemical properties were investigated in detail. The Sn-Sb-RuO_x interlayer played a very important role in enhancing the stability of the PbO₂ coating electrodeposited at a low current density. The scanning electron microscopy results showed that the cracks in the Sn-Sb-RuO_x coating were larger than those in the Sn-SbO_x coating. Moreover, the Ti/Sn-Sb-RuO_x/β-PbO₂ coating had many large pits with pore diameters in the range of 50–180 μm and pore depths of 2 was investigated by cyclic voltammetry. Compared to the compact β-PbO₂ anode, the porous β-PbO₂ anode showed superior electrocatalytic activity and electrochemical stability. A service life of 96 h was achieved for this anode under the accelerated-life-test conditions at a current density of 1 A/cm² in a solution of 150 g/L H₂SO₄ and 1 g/L Cl⁻.