Hierarchical mesoscale assembly of PbO2 on 3D titanium felt/TiO2 nanotubular array electrode for anodic decolourisation of RB-5 dye

Hierarchical PbO₂ nanoparticles (NPs) were grown by hydrothermal method on TiO₂ nanotubes (NTs) at 3D titanium felt, which is simple and scalable method. TiO₂ NTs were formed on titanium felt by anodising at 25 °C in environmentally friendly methanesulphonic acid solution. The growth of PbO₂ on the TiO₂ NTs depended on immersion time during hydrothermal synthesis and followed a LaMer-Dinegar burst kinetic model of nucleation and growth. PbO₂ formation began with rapid nucleation, followed by mesoscale assembly due to organic capping of poly(vinylpyrrolidinone). The electrochemical performance of 3D electrode was recorded in pH 3 sodium sulphate solutions containing Reactive Black 5 (RB-5) azo dye at 25 °C. The resulting hierarchical 3D electrode achieved 98% decolourisation after 50 min of anodic oxidation with a first order batch decay rate of 0.0875 min⁻¹.