Reductive desorption

Figure 8.4 Cyclic voltammograms of one to five layers of bis-bipyridinum cyclophane (1) cross-linked AuNPs at an ITO electrode showing adsorption (oxidation) and desorption (reduction) of oxygen at the NP surface corresponding to surface area. 1.0 M H2S04, scan rate = 50 mV s 1. Inset Calibration curve is the number of AuNPs cm 2 (n) versus number of layers.4 (Reprinted with permission from A. N. Shipway et al., ChemPhysChem 2000,1, 18-52. Copyright Wiley-VCH Verlag GmbH Co. KGaA.)...

One of the most important properties of these OMS and OL systems is their ability to lose and recover oxygen.92, 3,94,95 Temperature programmed desorption, reduction, Oxidation, and studies of lattice oxygen mobility and structural stability studies have been done on a variety of systems. A review of these and similar open framework structures has recently been submitted. 96... 

Major reactions, including adsorption/desorption, reduction-oxidation (redox), precipitation, and dissolution have to be considered when the EO flow passes through the barrier. For the target contaminant in solution, Cr(VI), the dominant reaction... 

Temperature programmed desorption, reduction, oxidation and flow chemisorption for the characterisation of heterogeneous catalysts. Theoretical aspects, instrumentation and applications... 

Termination, desorption (reduction by surface hydride giving an aikane or by hydride elimination giving an olefin)... 

FIGURE 8.32 Cyclic voltammogram of nanoscale Pt on Vulcan carbon in deaerated 0.1 M HCIO4 showing the potential regions for adsorption and desorption/reduction at potentials more positive than 0.6 V, and H... 

Fig. 4.3 Experimental setups for temperature-programmed desorption, reduction and oxidation, (a) The reactor is placed inside the furnace which is connected with temperature programmer. Detection of evolved gas(es) is performed by monitoring the variations in thermal conductivity of gas mixture, (b) The TPD apparatus equipped with mass spectrometer as a detector [5]...

Thermal Desorption. Thermal desorption is an innovative treatment that has been appHed primarily to soils. Wastes are heated to temperatures of 200 to 600°C to increase the volatilization of organic contaminants. Volatilized organics in the gas stream are removed by a variety of methods including incineration, carbon adsorption, and chemical reduction. 

U.S. EPA, Eco Eogic International Gas-Phase Chemical Reduction Process, The Thermal Desorption Enit Applications Analysis Report, EPA/540/AR-94/504, Washington, D.C., 1994. 

The adsorption of carbon monoxide retards the reduction reaction with the rate constant k, followed by the desorption reaction with a rate constant k in the overall rate equation... 

Hydrogenation of aromatics under mild conditions gives mainly the all-cis isomer as if hydrogen addition takes place from only one side of the molecule (23,24). Reductions under more vigorous conditions may give other isomers by isomerization of the initially formed all-cis product. Under mild conditions, other isomers are accounted for by desorption and readsorption in a new orientation of intermediate olefins, as well as by double-bond migration in the... 

The ionic current intensity corresponding to the peak at 169 amu was analyzed under isothermal and polythermal conditions [383]. It was found that in a gaseous atmosphere, the intensity changes are in correlation with the CO content and in negative correlation with the C02 content. The presence of CO in vacuum systems equipped with heating elements is usually related to thermo-cycling and desorption of CO by nickel atoms [386]. Based on the above, the presence of NbF4+ ions in mass spectra is most probably related to the niobium reduction process, which can be represented as follows ... 

Characterization is an important field in catalysis. Spectroscopy, microscopy, diffraction and methods based on adsorption and desorption or bulk reactions (reduction, oxidation) all offer tools to investigate the nature of an active catalyst. With such knowledge we hope to understand catalysts better, so that we can improve them or even design new catalysts. 

Figure 4.20. Experimental set-ups for temperature programmed reduction, oxidation and desorption. Upper left The reactor is inside the oven, the temperature of which can be increased linearly with time. Gas consumption by the catalyst is monitored by the change in thermal conductivity of the gas mixture it is essential to remove traces of water, etc. because these would affect the thermal conductivity measurement. Lower-left ...

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