Enhanced photoelectrocatalytic degradation of methylene blue using TiO2/silver nanowires composites

Silver nanowires (AgNWs) were synthesized using the polyol method and utilized to fabricate transparent conductive films. A bilayer TiO₂/AgNWs structure was employed for the photoelectrocatalytic degradation of methylene blue (MB). While TiO₂ photocatalysis for MB degradation did not suffer from overpotential issues, applying a bias voltage significantly enhanced catalytic activity. Compared to ITO conductors, AgNWs demonstrated superior photoelectrocatalytic performance, likely due to their increased interfacial contact and rapid charge transport within the TiO₂ matrix, effectively suppressing electron–hole recombination. The application of an external voltage further improved catalytic efficiency by promoting charge separation and generating additional hydroxyl radicals. The active surface area and sheet resistance were influenced by the thickness of the TiO₂ layer, impacting electron transport and charge recombination rates. MB degradation under anodic conditions was more efficient than under cathodic conditions, as the anodic electrode effectively extracted excited electrons, enhancing charge separation. Although bias voltage improved the catalytic activity of TiO₂/AgNWs catalysts, it did not change the reaction order and the ratio of residual carbon.