A facile route to synthesize a Tint-RuO₂ electrocatalyst for electro-generated active chlorine production

This study aimed to fabricate a novel TiNT-RuO₂ electrocatalyst to produce active chlorine with the capacity to oxidize recalcitrant organic matter. Titanium oxide nanotubes (TiNTs) were first grown via Ti foil anodization in potentiostatic mode in an ethylene glycol solution containing H₂O and NH₄F and then annealed at 450°C in air. RuO₂ nanoparticles were deposited on the TiNTs using a hybrid strategy that included pulsed electrodeposition of the Ru nanoparticles, followed by thermal treatment. X-ray diffraction (XRD) only revealed peaks related to metallic Ti and anatase (TiO2) for the TiNTs, whereas additional peaks associated with the tetragonal RuO₂ structure were shown for TiNT-RuO₂. Scanning electron microscopy showed a well-organized structure for the TiNTs with an average inner diameter of approximately 185 nm for the NTs, while RuO₂ nanoparticles (size <10 nm) were homogenously deposited on the walls and around the openings of the TiNTs. TiNT-RuO₂ preferred the active chlorine formation over oxygen evolution owing to the presence of the RuO₂ nanoparticles. Rapid degradation testing revealed complete elimination of picloram (PCL) in 2 h when 10 mA cm⁻² was imposed on the TiNT-RuO₂, whereas 48% of the 2,4-dichlorophenoxyacetic acid (2,4-D) was removed under the same conditions using the electro-generated active chlorine on the TiNTs.