Photocatalytic degradation of methylene blue by a cocatalytic PDA/TiO₂ electrode produced by photoelectric polymerization

Abstract

<p>This study reports a new method for photocatalysts to degrade organic dyes on organic semiconductors.</p>

Photoelectrochemical Enzyme Biosensor Based on TiO2 Nanorod/TiO2 Quantum Dot/Polydopamine/Glucose Oxidase Composites with Strong Visible-Light Response

“…After the PDA was loaded, R a of the composite material was substantially reduced, indicating that photopolymerization could potentially enable the polymer film material to grow uniformly anywhere on the electrode surface (Figure 2G−I). 26 The aforementioned data all indicate that PDA was evenly loaded onto the electrode surface.…”

Band Gap Engineering toward Semimetallic Character of Quinone-Rich Polydopamine

“…However, when the pH of electropolymerization was neutral or slightly alkaline, the emergence of several peaks is observed in the visible and NIR range, with a simultaneous decrease of the absorption edge. The origin of these peaks is either from the presence of discrete energy levels introduced into the system through electropolymerization or the geometry-dependent scattering observed in several works. , Moreover, the enhancement of the spectral signal in the visible range is larger compared to the other works reporting modification of TiO 2 with PDA. , …”

“…51,52 Moreover, the enhancement of the spectral signal in the visible range is larger compared to the other works reporting modification of TiO 2 with PDA. 48,53 The described effects also have a profound influence on the photoelectrochemical activity (Figure 4d,e). LSV curves recorded under cyclic dark−light exposure during polarization show that there is an increase in photocurrents after modification of pure nanotubes in the potential range from −0.2 to +1.0 V. This improvement is observed only when PDA is polymerized at a pH of 7.5 or greater.…”

“…Similar coverages were obtained with photo-electropolymerization of dopamine on TiO 2 nanorods. 48 Moreover, a set of SEM pictures of various areas of the sample at 27,49,50 �suggests the formation of PDA consisting mostly of catecholic units such as DA, LDC, and DHI. This is in agreement with the overall reaction scheme, where the presence of H + ions shifts the reaction toward catecholic products (eq 3)…”

“…This effect, attributed to the absorption by discrete levels of PDA, is greater than previously observed in the literature for TiO 2 |PDA junctions. 48 Presumably, the key factor explaining the difference is hydrogenation before PDA deposition. Although this information is insufficient to conclude that PDA is stable after UV light exposure, another set of studies have been performed to verify this issue and have been exhaustively discussed in the Supporting Information.…”