Decolourisation of reactive black-5 at an RVC substrate decorated with PbO2/TiO2 nanosheets prepared by anodic electrodeposition.

Reticulated vitreous carbon (RVC) substrates were coated with a composite of PbO₂ and titanate nanosheets (TiNS) by anodic electrophoretic depostion. The structure and morphological characteristics of the coating were evaluated by field emission scanning electron microscopy (FESEM) and Raman spectroscopy. The TiNS/PbO₂/RVC coating contained the anatase phase and showed a well-defined, microporous morphology with hydrophilic character along the length and thickness of the RVC struts. Electrochemical and photocatalytic activity of the coatings facilitated RB-5 dye degradation as a model organic pollutant in wastewater. The electrochemical decolourisation involves the generation of hydroxyl free radicals over the TiNS/PbO₂/RVC anode composite surface, whereas photocatalytic decolourisation was driven by the synergetic photocatalytic effect imparted by the photoinduced holes and free electron acceptors. The photocatalytic properties of the TiNS/PbO₂ coating were achieved by calcination at 450 °C for 60 min in air which converted the titanate phase to anatase and modified its surface area. This enabled 98% electrochemical decolourisation of the RB-5 dye solution (measured by visible absorption at 597 nm) in a time of 60 min.ᅟ<graphic></graphic> [ABSTRACT FROM AUTHOR]