Improved Photocatalytic Activity of Polysiloxane TiO₂ Composites by Thermally Induced Nanoparticle Bulk Clustering and Dye Adsorption

Abstract

Fine control of nanoparticle clustering within polymeric matrices can be tuned to enhance the physicochemical properties of the resulting composites, which are governed by the interplay of nanoparticle surface segregation and bulk clustering. To this aim, out-of-equilibrium strategies can be leveraged to program the multiscale organization of such systems. Here, we present experimental results indicating that bulk assembly of highly photoactive clusters of titanium dioxide nanoparticles within an in situ synthesized polysiloxane matrix can be thermally tuned. Remarkably, the controlled nanoparticle clustering results in improved degradation photocatalytic performances of the material under 1 sun toward methylene blue. The resulting coatings, in particular the 35 wt % TiO2-loaded composites, show a photocatalytic degradation of about 80%, which was comparable to the equivalent amount of bare TiO2 and two-fold higher with respect to the corresponding composites not subjected to thermal treatment. These findings highlight the role of thermally induced bulk clustering in enhancing photoactive nanoparticle/polymer composite properties.

Self-Cleaning Bending Sensors Based on Semitransparent ZnO Nanostructured Films

“…The use of a light source offering similar intensity and spectral composition to natural sunlight is fundamental to testing the photocatalytic efficiency of the investigated systems under indoor conditions simulating real-life scenarios. The MB photodegradation kinetics was evaluated by monitoring the decay of absorbance intensity at λ = 664 nm, as already shown in our previous work . As reported in Figures S11 and S12, with the increase of irradiation time, the decrease of the absorption peak intensity was observed in the investigated samples, i.e., ITO, seeded ITO, seedless ZnO, and seeded ZnO, in the absence or in the presence of bending.…”

“…The MB photodegradation kinetics was evaluated by monitoring the decay of absorbance intensity at λ = 664 nm, as already shown in our previous work. 65 As reported in Figures S11 and S12 , with the increase of irradiation time, the decrease of the absorption peak intensity was observed in the investigated samples, i.e., ITO, seeded ITO, seedless ZnO, and seeded ZnO, in the absence or in the presence of bending. It was found that the photocatalytic degradation rate can be modeled by a pseudo-first-order kinetic model in which the rate constant ( k ) is evaluated by the linear regression model expressed by ln( C / C 0 ) = kt , where C 0 is the concentration after adsorption/desorption equilibrium and C is the concentration after a given exposure at 1 sun irradiation time of the MB aqueous solution ( Figure 8 c).…”

Fabrication of a Covalent Organic Framework-Based Heterojunction via Coupling with ZnAgInS Nanosphere with High Photocatalytic Activity

“…Photocatalysis, as a sunlight-driven green technique, has been identified as one of the most promising solutions for removal of organic pollutants. − Generally, a superior photocatalyst requires sufficient sunlight absorbance, particularly in the visible-light range, and the effective separation and utilization of the photogenerated charge carriers. To this point, many photocatalysts have been developed for the degradation of organic pollutants.…”

Blue light activated photodegradation of biomacromolecules by N-doped titanium dioxide in a chitosan hydrogel matrix

“…Titanium dioxide (TiO 2 ) and related materials are currently among the most effective photocatalysts, and they are widely exploited in several fields such as photovoltaics [1][2][3], cultural heritage [4][5][6], and environmental treatments [7][8][9]. Indeed, upon irradiation TiO 2 -based materials can induce photocatalysis, a light-triggered process consisting in the activation of a cascade of photochemical reactions mediated by highly reactive radical species.…”