Photocatalytic Decomposition Of NO Research Articles

The Photocatalytic Decomposition of Nitric Oxide on the Silver(I) Ion-exchanged ZSM-5 Catalyst

Abstract UV irradiation of the Ag+/ZSM-5 catalyst prepared by an ion-exchange method in the presence of NO led to the photocatalytic decomposition of NO into N2, N2O and NO2 at temperatures as low as 298 K. Investigations of in-situ XANES, ESR, and DRS of the Ag+/ZSM-5 catalyst as well as the effective wavelengths of the irradiated UV light indicated that the excited state of the Ag+ ion included within the zeolite cavities plays a significant role in the photocatalytic decomposition of NO molecules.

Approach to photocatalysis at the molecular level Design of photocatalysts, detection of intermediate species, and reaction mechanisms

The characterization of the Cu +/ZSM-5 catalysts prepared via reduction of ion-exchanged Cu 2+/ZSM-5 samples and highly dispersed Ti-oxide catalysts anchored on Vycor glass has been undertaken by in-situ photoluminescence, EPR, XAPS (XANES and FT-EX-AFS), and FT-IR spectroscopy. UV-irradiation of the Cu +/ZSM-S catalyst in the presence of NO leads to the direct photocatalytic decomposition of NO into N 2 and O 2 at normal temperatures. UV-irradiation of the highly dispersed anchored Ti-oxide catalyst in the presence of CO 2 and H 2O also leads to the evolution of CH 4, CO, and CH 3OH at normal temperatures. The clarification of the coordination structure of the active surface sites and the direct detection of the reaction precursors and intermediate species in these photocatalytic systems contributed significantly in characterizing the molecular scale reaction mechanisms. Based on these results, the design of highly concentrated and efficient photocatalysts has successfully been achieved by application of the sol-gel method.

Photocatalytic decomposition of dinitrogen oxide on Cu-containing ZSM-5 catalyst

Photodecomposition of dinitrogen oxide (N2O) into N2 and O2 on Cu-exchanged ZSM-5 zeolite (ion-exchange degree, 145 %), degassed at 723 K, proceeds catalytically at 278 K. The dependence of the decomposition rate on the wavelength of the irradiated light reveals the importance of the excitation of monovalent Cu ions (<300 nm) in the photocatalytic decomposition of N2O. The rate of decomposition can be expressed by the rate equation: r=a[N2O]//([N2O]+b[O2]½), where a and b are constants, and a is proportional to the light intensity.The desorption of O2 from the surface is not a rate-determining step in the photodecomposition or the thermal decomposition of N2O on the zeolite which occurs with an apparent activation energy of 37 ± 3 kJ mol–1.

Photocatalytic Decomposition of N2O at Room Temperature

Abstract Decomposition of N2O into N2 and O2 at room temperature was demonstrated on a Pt/TiO2 photocatalyst in the presence of water vapor. The photocatalytic activity was enhanced by the participation of photocatalytic decomposition of water.

Approach to De-NOx-ing Photocatalysis. Photocatalytic Decomposition of NO on Cu+/SiO2 Catalyst Prepared via Ion-exchange Method

Abstract Cu2+ ions supported onto SiO2 (Cu2+/SiO2) prepared by an ion-exchange method are reduced to Cu+ ions when the Cu2+/SiO2 sample is evacuated above 573 K. Cu+/SiO2 catalyst decomposes NO photocatalytically and stoichiometrically at 275 K. The excited state of the Cu+ ions plays a significant role in the photocatalytic decomposition of NO on the Cu+/SiO2 catalyst.