Decomposition Of Gaseous Acetaldehyde Research Articles

Visible light photocatalytic activity induced by Rh(III) modification on the surface of BiOCl

Using impregnation technique, a small amount of Rh(III) clusters has been grafted on the BiOCl microflowers. The samples are characterized by X-ray diffraction, scanning electron microscopy coupled with high energy distribution X-ray, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflectance spectroscopy. The photocatalytic activities are investigated by the decomposition of gaseous acetaldehyde under irradiation of visible light. The bare BiOCl microflowers exhibit the limited visible light photocatalytic activity because of its wide band gap. After surface modification of Rh(III) clusters, the Rh(III)-BiOCl samples show an enhanced photocatalytic activity for the decomposition gaseous acetaldehyde under visible light irradiation. It is found that the Rh(III) clusters play an important role for the visible light absorption, probably through the electron transfer between Rh(III) clusters and the BiOCl, as well as the redox reaction centers for the multi-electron reduction of O2.

Rapid removal and decomposition of gaseous acetaldehyde by the thermo- and photo-catalysis of gold nanoparticle-loaded anatase titanium(IV) oxide

Gold nanoparticles (NPs) with a mean particle size ranging from 2.1 to 7.4nm were loaded on anatase TiO2 particles (Au/TiO2) by the heating temperature-varied deposition precipitation technique. This study has shown that Au/TiO2 with Au particle size <3nm and TiO2 surface area >50m2g−1 can be a promising environmental catalyst for the rapid removal and decomposition of gaseous acetaldehyde in a closed space. The Au loading on TiO2 causes a drastic enhancement of the acetaldehyde adsorption in the dark, and the adsorption amount increases as the Au particle size decreases. This result originates from the thermocatalytic activity of Au/TiO2 for the oxidation of acetaldehyde to acetic acid under ambient conditions. The resulting acetic acid spontaneously moves to the TiO2 surface due to the great adsorptivity for the carboxyl group. Consequently, the acetaldehyde adsorption amount strongly depends on the TiO2 surface area in addition to the Au particle size. UV-light irradiation of acetaldehyde (or acetate)-adsorbed Au/TiO2 leads to the complete decomposition to carbon dioxide by the high photocatalytic activity of anatase TiO2.

Adsorption and Plasma Decomposition of Gaseous Acetaldehyde on Fibrous Activated Carbon

In this paper, adsorption and nonthermal plasma decomposition of gaseous acetaldehyde were studied using barrier-discharge plasma reactor, in which fibrous activated-carbon textile (ACT) was used as both an electrode and adsorbent. The acetaldehyde molecule was adsorbed on ACT depending on the concentration of gaseous acetaldehyde. When acetaldehyde concentration was 500 ppm or lower, the amount of adsorbed acetaldehyde was estimated by Henry's equation. The adsorbed acetaldehyde on ACT sheet was decomposed by the barrier-discharge plasma generated by applying high-voltage ac regulated by a neon transformer. When 200 ppm of acetaldehyde was fed continuously to the plasma reactor, 30, 45, and 120 ppm of acetaldehyde remained, with applied voltage of 13, 10, and 5 kVp, respectively. We also checked electric energy efficiency on the decomposition of acetaldehyde. Although 10 or 13 kVp of plasma has the same energy efficiency, 5 kVp of plasma was less effective for the decomposition because of unstableness of plasma generation. These results suggested that 10 kVp or more high-voltage ac is suitable for the decomposition of acetaldehyde by using ACT as the high-voltage electrode.

Decomposition of Gaseous Acetaldehyde Using Barrier Discharge Plasma with Fibrous Activated Carbon as an Electrode

Adsorption and nonthermal plasma degradation of gaseous acetaldehyde was studied in a novel plasma discharge reactor, in which fibrous activated carbon was used as both an electrode and adsorbent. After a sheet of fibrous activated carbon put onto a glass plate was saturated with 50 ppm of acetaldehyde gas, 10 kV of high voltage AC was applied to fibrous activated carbon. The barrier discharge was generated at around the sheet of fibrous activated carbon. Acetaldehyde adsorbed in the fibrous activated carbon was removed during the plasma treatment, and complete decomposition of acetaldehyde was achieved within 60 min. We also examined the recycle of fibrous activated carbon. After complete degradation of adsorbed acetaldehyde in fibrous activated carbon with discharge was finished, the fibrous activated carbon could be reusable for the adsorbent and degradation with discharge. The fibrous activated carbon used in our study was able to reuse at least five times without any significant decrease of adsorption ability. These results suggested that continuous treatment with spontaneous adsorption and nonthermal plasma degradation of VOCs is possible by using fibrous activated carbon as the high voltage electrode.

Aerogel processing of MTi 2O 5 (M = Mg, Mn, Fe, Co, Zn, Sn) compositions using single source precursors: synthesis, characterization and photocatalytic behavior

Oxide semiconductor photocatalysts based on TiO 2 (band gap of 3.2 eV) are normally used to destroy organics under UV irradiation. Currently we have been focused on the aerogel synthesis of nanocrystalline photocatalysts that will destroy organic compounds such as acetaldehyde using visible and UV radiations. Herein we report the results of our attempts to synthesize mixed metal oxides of the type MTi 2O 5 (M = Mg, Mn, Fe, Co, Zn, and Sn). The preparation method involves the formation of a single source precursor by the condensation reaction of Ti(OPr n ) 4 with M(OAc) 2, followed by their (M[O Ti(OPr n ) 3] 2) hydrolysis and drying under supercritical conditions by a modified aerogel process. Product compositions, oxide structure types, and morphology were characterized by powder X-ray diffraction, scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDXA), and BET surface area measurements. Only for Mg, the stoichiometry MgTi 2O 5 with pseudo-brookite structure type was obtained, while the composites MTiO 3/TiO 2 were obtained for M = Fe, Co and Zn. Photocatalytic behavior of these composite oxides were tested by the decomposition of gaseous acetaldehyde under UV light (320 nm < λ < 400 nm). Of these, CoTiO 3/TiO 2 showed an interesting catalytic behavior; it decomposed acetaldehyde in the dark, at room temperature. Other mixed metal oxides such as MgTi 2O 5, and composites such as FeTiO 3/TiO 2 and ZnTiO 3/TiO 2 decomposed acetaldehyde only under UV light (not under visible light or in the dark). The photocatalytic activity was compared with the reference degussa P25 TiO 2 photocatalyst.

Preparation of Transparent TiO2 Thin Film Photocatalyst and Its Photocatalytic Activity

Abstract Transparent TiO2 thin films with high photocatalytic activity were prepared on glass substrates via the sol-gel method from tetraisopropyl titanium ethanol solution containing polyethylene glycol and diethylene glycol. Transparency of these TiO2 thin films was 80% in the visible region. Photocatalytic activity of the TiO2 thin films was studied using the decomposition of gaseous acetaldehyde. We found that the quantum yield with those films was similar to that with one of the most photoactive commercial TiO2 powders, Degussa P-25.

Thermal Decomposition of Certain Gaseous Organic Compounds

IN a letter in NATURE of March 30, I asked for suspension of judgment regarding a difference of opinion between Mr. Hinshelwood and his colleagues on one hand, and myself and my co-workers on the other, with regard to the possibility of measuring the rate of chemical reaction in the thermal decomposition of gaseous acetaldehyde by observing the rate of increase of pressure at constant volume, and also as to the mechanism of the chemical process involved. Mr. Hinshelwood has published an account of his latest work on this subject, and Mr. R. V. Seddon and I have carried on our own work to a point at which publication is possible. We believe that our results support our views on the case.