Photocatalytic Conversion of Nitric Oxide on Titanium Dioxide: Cryotrapping of Reaction Products for Online Monitoring by Mass Spectrometry

Abstract

Details of coupling a catalytic reaction chamber to a liquid nitrogen-cooled cryofocuser/triple quadrupole mass spectrometer for online monitoring of nitric oxide (NO) photocatalytic reaction products are presented. Cryogenic trapping of catalytic reaction products, via cryofocusing prior to mass spectrometry analysis, allows unambiguous characterization of nitrous oxide (N 2 O) and nitrogen oxide species (i.e., NO and nitrogen dioxide (NO 2)) at low concentrations. Results are presented, indicating that the major photocatalytic reaction product of NO in the presence of titanium dioxide (TiO 2) P25 and pure anatase catalysts when exposed to ultraviolet (UV) light (at a wavelength of 365 nm) is N 2 O. However, in the presence of rutile-rich TiO 2 catalyst and UV light, the conversion of NO to N 2 O was less than 5% of that observed with the P25 or pure anatase TiO 2 catalysts.

Hierarchical synthesis of corrugated photocatalytic TiO2 microsphere architectures on natural pollen surfaces

“…(For interpretation of the references to colour in text, the reader is referred to the web version of this article.) storage of NO(g) includes oxidation steps [11,34,43,44] involving the formation of NO 2 (g), where the eventual storage of NOx species on the catalyst surface may occur in the form of chemisorbed NO, NO 2 /NO 2 − , N 2 O, and NO 3 − . Thus, maximizing the oxidative NOx storage at the solid state, while simultaneously minimizing the gas phase release of toxic NO 2 (g) requires optimization of the chemical, electronic and surface structure of the photocatalysts.…”

“…One of the most abundant renewable energy sources that can be exploited in heterogeneous catalysis applications in an environmentally friendly and economical manner is the solar energy. Thus, there exists an immense demand to develop novel photocatalytic materials using innovative synthetic methodologies [6][7][8][9][10][11].…”

Core‐crown Quantum Nanoplatelets with Favorable Type‐II Heterojunctions Boost Charge Separation and Photocatalytic NO Oxidation on TiO2

“…Thus, N 2 and/or N 2 O formation can readily be ruled out in the current study. [17] It is apparent in Figure 7b that photocatalytic NO x abatement action continues after this initial stage during the entire duration of the activity test. Thus, total NO x abatement effect can be calculated by integrating the relevant concentration traces for the entire duration of the PHONOS test.…”

“…In this regard, photocatalytic oxidative NO x storage (PHONOS) [12][13][14][15][16][17][18] presents an appealing alternative as it can store airborne NO x in the solid state under ambient conditions after the point of NO x discharge to the atmosphere. This approach requires the presence of only sunlight, water and oxygen (all of which are abundantly present in the atmosphere) and a photocatalytically active material.…”

Room‐Temperature Photocatalytic Decomposition of N2O over Nanobelt‐Like Bi2MoO6

“…Nevertheless, it has to be acknowledged that TiO 2 could only be initiated under the excitation of ultraviolet light (λ < 387.5 nm), which on account of a large band gap energy (∼3.2 eV). Moreover, the relatively poor solar efficiency and slow reaction rate further hinder its wide application ,. Consequently, much effort have been devoted to reducing the recombination of photogenerated electron‐hole pairs by extending the light absorption from UV to visible light region .…”