Download [UPDATED] Media 777 HALIM Bin

The inadequate understanding of plasma chemistry probably lies in the lack of analytical studies able to provide molecular information: thus UV Vis absorption and emission spectroscopies have been employed for a number of years in the study of plasma, as may be expected given the inevitable emission of light from plasma. Such studies give useful information on excited species (see, for example, [22,23,24,25,26]). However, as an analogy, the field of electrochemistry underwent a paradigm shift in the 1980s with the advent of, in particular, in situ FTIR spectroscopy with its ability to provide molecular information and hence determine the identity of adsorbed and solution intermediates and products [27, 28]. It is generally recognised that emission spectroscopy and the standard analytical techniques currently employed in NTP research need to be complemented by methods able to provide molecular information such as FTIR spectroscopy [1]. Thus, the field of NTP plasma catalysis is at a similar stage of development as electrochemistry was in the mid-1980s: whilst the plasma/catalyst surface has not been investigated extensively with in situ FTIR, such studies have started to appear. There are a number of studies on the downstream analysis of the exhaust from NTPs, see for example [29], but actual studies of the plasma glow with IR spectroscopy [30] or of the catalyst surface in contact with a plasma is only a recent phenomenon. Thus, the quality of the information that can be obtained from in situ FTIR is exemplified by the work of Li et al. on the deposition of Si from hexamethyldisiloxane plasma [31], Rivallan and colleagues on the conversion of IPA at Al2O3 [32], Stere et al. [33] on the hydrocarbon-assisted NOx removal from simulated diesel fuel over silver-based catalysts, Rodriguez et al. [34] on the conversion of IPA at Al2O3, CeO2 and TiO2 and Jia and Rousseau on the plasma-assisted reaction of acetone at CeO2 [35]. These studies employed the Diffuse Reflectance approach [33, 34], transmission through the catalyst as a wafer [32, 35] or passed the IR beam through the plasma glow above the solid surface [30]. Rivallan et al. [36] employed step scan FTIR spectroscopy to study the gas phase reduction of CO2 in a tube reactor (i.e. they did not study the catalyst/plasma interface): however, they saw no reaction products or intermediates just the loss of CO2, although they did achieve a time resolution of ca. 400 μs.

Download media 777 HALIM bin

041b061a72