Two-step facile synthesis of Co3O4@C reinforced PbO2 coated electrode to promote efficient oxygen evolution reaction for zinc electrowinning. Issue 17 (6th April 2022) - Jiang, Wenhao
Abstract : We synthesized a PbO2 -coated electrode consisting of three layers, with Pb–0.6%Sb alloy as the substrate, α-PbO2 as the intermediate layer, and the outermost β-PbO2 -Co3 O4 @C as the active layer for boosting OER activity. Abstract : The conventional Pb–Ag alloy possesses a high oxygen evolution reaction overpotential, poor stability, and short service life in acidic solutions, making it an unsuitable sort of anode material for the zinc electrowinning process. Therefore, a layered carbon-covered cobalt tetroxide (Co3 O4 @C)-reinforced PbO2 -coated electrode is fabricated via a facile two-step pyrolysis-oxidation and subsequent electrodeposition process. As a result, the reinforced PbO2 -coated electrode exhibits a low OER overpotential of 517 mV at 500 A m −2 and a Tafel slope of 0.152 V per decade in a zinc electrowinning simulation solution (0.3 M ZnSO4 and 1.53 M H2 SO4 ). The reduced overpotential of 431 mV at 500 A m −2 compared to traditional Pb–0.76%Ag alloy leads to improved energy savings, which is attributable to the presence of Co3 O4 @C to refine the grain size and thus increase the effective contact area. Moreover, the reinforced PbO2 -coated electrode has a prolonged service life of 93 h at 20 000 A m −2 in 1.53 M H2 SO4 . Therefore, an accessible and efficient strategy for preparing a coated electrode to improve OER performance for zinc electrowinning is presented in this research.