Facile synthesis MnCo2O4 modifying PbO2 composite electrode with enhanced OER electrocatalytic activity for zinc electrowinning

In industrial zinc electrowinning, the anodic oxygen evolution reaction (OER) has sluggish kinetics leading to ultrahigh overpotential and energy consumption. Herein, a sandwich-like MnCo2O4 modifying PbO2 composite electrode was fabricated via chemical-bath-deposition and electrodeposition. Consequently, the synthesized PbO2 electrode exhibits low Tafel slope of 0.17 V per decade and an operating potential of 1.68 V vs. SCE for 500 A m(-2) in a simulated solution containing 150 g L-1 H2SO4 and 50 g L-1 Zn2+. Compared with traditional Pb-0.76Ag alloy, the overpotential at 500 A m(-2) decreased by 357 mV, which ascribe to the incorporation of MnCo2O4 minoring crystal grain size and charge transfer resistance and enlarging active surface area. Furthermore, the composite electrode shows robust durability as long as 95 h at 15,000 A m(-2) in 0.5 M H2SO4 electrolyte. Hence, this study offers a facile synthesis route to prepare composite electrodes for zinc electrowinning and provides deep insight into the relationship among modifying substances, microstructures, and electrocatalytic activity.

Automated summary

A sandwich-like MnCo2O4 modifying PbO2 composite electrode was successfully fabricated for zinc electrowinning, exhibiting low Tafel slope and operating potential in a simulated solution, along with robust durability in electrolyte. This study provides a facile synthesis route for composite electrodes and deep insight into the relationship among modifying substances, microstructures, and electrocatalytic activity in zinc electrowinning.