Synthesis and Photocatalytic Activity of Cerium-Modified CdS-TiO2Photocatalyst for the Formaldehyde Degradation at Room Temperature

Synthesis and photocatalytic activity of a lanthanum doped CoFe2O4/TiO2 nanocomposite for photodegradation of methylene blue organic dye

In this study, a 0.2CoFe2O4/0.8TiO2-5%La nanocomposite was synthesized by a co-precipitation and a hydrothermal method and then was applied as a high activity photocatalyst for degradation of methylene blue under visible light irradiation. The 0.2CoFe2O4/0.8TiO2-5%La material was characterized by X-ray diffraction, Raman spectra, scanning electron microscope/transmission electron microscope and UV-Vis techniques. The photocatalytic activity of the material was initially investigated through the decomposition of methylene blue. The synthetic 0.2 CoFe2O4/0.8 TiO2-5% La showed excellent photocatalytic activity for degradation of methylene blue under visible light irradiation. Methylene blue could be degraded by more than 99.14% after only 50 min.

Composite CdS/TiO2 Powders for the Selective Reduction of 4-Nitrobenzaldehyde by Visible Light: Relation between Preparation, Morphology and Photocatalytic Activity

A series of composite CdS/TiO2 powders was obtained by nucleation of TiO2 on CdS nanoseeds. This combination presents the appropriate band edge position for photocatalytic redox reactions: visible light irradiation of CdS allows the injection of electrons into dark TiO2, increasing the lifetimes of separated charges. The electrons have been used for the quantitative photoreduction of 4-nitrobenzaldehyde to 4-aminobenzaldehyde, whose formation was pointed out by 1H NMR and ESI-MS positive ion mode. Concomitant sacrificial oxidation of 2-propanol, which was also the proton source, occurred. The use of characterization techniques (XRD, N2 adsorption-desorption) evidenced the principal factors driving the photocatalytic reaction: the nanometric size of anatase crystalline domains, the presence of dispersed CdS to form an extended active junction CdS/anatase, and the presence of mesopores as nanoreactors. The result is an efficient photocatalytic system that uses visible light. In addition, the presence of TiO2 in combination with CdS improves the stability of the photoactive material, enabling its recyclability.

Thermally treated zeolitic imidazolate framework-8 (ZIF-8) for visible light photocatalytic degradation of gaseous formaldehyde

The development of wide-spectrum responsive photocatalysts for efficient formaldehyde (HCHO) removal is highly desired yet remains a great challenge. Here we successfully converted zeolitic imidazolate framework-8 (ZIF-8), one of the most well-studied metal-organic frameworks (MOFs), from routine ultraviolet-driven to novel broad-spectrum-driven photocatalyst via a facile thermal treatment. The isocyanate groups (-N[double bond, length as m-dash]C[double bond, length as m-dash]O) formed in the thermally treated ZIF-8 (ZIF-8-T) is crucial in enabling the superior photocatalytic performance in formaldehyde degradation. Specifically, the best-performing ZIF-8-T sample showed around 2.1 and 9.4 times the HCHO adsorption amount and the solar photocatalytic degradation rate, respectively, of pristine ZIF-8. In addition, ZIF-8-T exhibited visible light (λ ≥ 400 nm) photocatalytic HCHO degradation performance, photo-converting 72% and nearly 100% of 20 ppm and 10 ppm HCHO within 1 hour, respectively. This work affords new insights and knowledge that inspire and inform the design and development of MOF-based photocatalysts with broad-spectrum responses for efficient air purification operations.

Preparation and characterization of Fe3O4@SiO2@TiO2–Co/rGO magnetic visible light photocatalyst for water treatment

With its low cost, high photocatalytic activity, high chemical stability and easy magnetic separation, Fe₃O₄@SiO₂@TiO₂–Co/rGO magnetic photocatalyst has a good application potential.