Constructing of Pb–Sn/α-PbO2/β-PbO2-Co2MnO4 composite electrode for enhanced oxygen evolution and zinc electrowinning

Abstract

Developing a highly efficient and stable electrode for oxygen evolution reaction (OER) in harsh conditions (∼1.63 M H2SO4) is desirable but still challenging. Herein, the paper describes Co2MnO4 modifying β-PbO2 (Pb–Sn/α-PbO2/β-PbO2-Co2MnO4) via thermal decomposition and subsequent electrodeposition. Consequently, the synthesized electrode presents a layer structure, where Pb–Sn alloy serves as the matrix, α-PbO2 functions as mid-layer to enhance the binding force between the matrix and β-PbO2, and β-PbO2-Co2MnO4 acts as active layer for OER. In addition, the obtained quasi–three–dimensional Pb–Sn/α-PbO2/β-PbO2-Co2MnO4 electrode exhibits the lowest overpotential of 571 mV for 50 mA cm−2 and a small Tafel slope of 207.1 mV dec−1 in 1.63 M H2SO4 electrolyte. Moreover, it shows the smallest corrosion rate of 0.13 mg cm−2 h−1 and the longest accelerated service life of 59 h at 2 A cm−2. Furthermore, it is used as an anode for zinc electrowinning, in which the cell voltage and power consumption for producing one–ton zinc are lower by 230 mV and 304.2 kW h as compared with the benchmark electrode of Pb-0.76%Ag alloy. Hence, this paper provides the strategy to design and construct non-precious, high–performance catalysts for electrolysis and other applications.