Optimization of Ti/TiO₂ Nanotube/Nano PbO₂ Anodes for Enhanced Electrocatalytic Degradation of Methylene Blue: Pulse vs Direct Current Approaches

This study focused on examining how the presence of a TiO 2 nanotube (NT) interlayer and decreasing particle size affects the electrochemical performance and service life of PbO 2 -coatings on a titanium substrate. The Ti/TiO 2 -NT/ β -PbO 2 and Ti/PbO 2 electrodes were synthesized using direct current with particle size of 3 μm and optimized current density values, while the Ti/TiO 2 -NT/nano β -PbO 2 electrodes with β -PbO 2 particle size of 35 nm were synthesized using a simple pulse electrodeposition method and optimized duty cycle. The results of cyclic voltammetry demonstrated that the Ti/TiO 2 -NT/nanoPbO 2 electrode exhibited a larger electrochemically active surface area, voltammetry charge values of 3.06 mC cm −2 , and a lower charge transfer resistance of 9.47 Ω.cm 2 compared to the Ti/TiO 2 -NT/microPbO 2 and Ti/PbO 2 , which had values of 9.26 and 14.62 mC cm −2 and 61.58 Ω.cm 2 , and 8900 Ω.cm 2 , respectively. Accelerated service life tests showed that the Ti/TiO 2 /nanoPbO 2 electrode (55 h) had a better service life than those of Ti/TiO 2 -NT/microPbO 2 and Ti/PbO 2 electrodes (50 and 18 h respectively). Moreover, the Ti/TiO 2 -NT/nano β -PbO 2 electrode showed the highest performance in degrading methylene blue in simulated wastewater by bulk electrolysis, with a removal efficiency of approximately 100% at optimal current density (60 mAcm −2 ), surpassing the efficiency of the Ti/TiO 2 -NT/microPbO 2 (76%) and Ti/PbO 2 electrodes (53%).