Xe lamp

The photocatalytic decomposition of water was carried out in a closed gas circulation system connected to a high-vacuum line. About 200 mg of a powdered catalyst was dispersed in pure distilled water and irradiated through a water filter with an Xe lamp operated at 400 W. Hydrogen and oxygen evolved in the gas phase were analyzed by a gas chromatograph which was directly connected to the reaction system. 

Photolysis Procedure. The solvent-cleaned Kevlar-29 fabric swatch (2.5 cm x 18 cm) was placed around the outside quartz tube inside the photolysis chamber, which was subsequently evacuated, before - - 02 (99%) was introduced to 0.2 atm. The photolysis chamber was preheated to the specified photooxidation temperature, before the Hg-Xe lamp was turned on. The temperature, which was held constant in the chamber by adjusting the air flow around the lamp, was monitored by a thermocouple placed next to the fabric sample inside the chamber. After the photooxidation had continued for the specified... 

A > 320 nm) from500 W Xe lamp at 40-50°C. Under these conditions n-hexadecane (C16H34) was converted to a mixture of H2 and C02 as follows ... 

Similar results have been reported for DMA/PEMA (14). Figure 11 shows data for DSAE/PPSQ. Although the same effect is present, it is quantitatively different. The reduction in T is about a factor of 3 for a film initially bleached to T=32%, while for DPA about the same reduction is seen with T(initial) = 8% thus it is apparently less severe for DSAE. The most interesting result is that DMA/PEMA, when irradiated under N2 at 260 nm (+/-8nm FWHM bandwidth) by an Hg-Xe lamp, shows absolutely no change in transmittance with a dose of 100 J/cm2 (15). Thus the antibleaching is an intensity dependent effect that is absent at low intensities and occurs only with the excimer laser (typically -0.1-1 mJ/cm2 in -35 nsec). 

These lamps show moderately good color rendering properties, the very broad spectrum being one of their main utilities. For instance, high-pressure Xe lamps or deuterium lamps are commonly used in optical spectroscopy techniques. 

In research laboratories, different types of light sources are used instead of solar radiation. In most cases the simulated spectrums have considerable deviation from the solar spectrum. Based on equation (3.6.9) Murphy et al [109] analyzed the maximum possible efficiencies for different materials according to their band gap in the case of solar global AM 1.5 illumination and xenon arc lamp, see Fig. 3.21. For example, anatase titania with a bandgap of 3.2 eV has a maximum possible efficiency of 1.3% under AM 1.5 illumination, and 1.7% using Xe lamp without any filter. For rutile titania these values are 2.2% and 2.3% respectively. 

Spray pyrolysis of ethanolic solutions of Fe(acetylacetone)3 or FeCls between 370°C and 450°C onto a glass substrate are reported for the fabrication of a-Fe20s thin-film photoanodes [75]. Upon illumination by a 150 W Xe lamp samples consistently demonstrate photocurrents of 0.9 mAcm , IPCE values up to 15%, and robust mechanical stability with no signs of photocorrosion for the undoped samples. With simultaneous multiple doping of 1% A1 and 5% Ti, an IPCE of 25% can be reached at 400 nm. Zn doping is known to induce p-type character in Ee20s thin film electrodes [76]. 

Pulse radiolysis was performed using e from a linear accelerator at Osaka University [42 8]. The e has an energy of 28 MeV, single-pulse width of 8 nsec, dose of 0.7 kGy, and a diameter of 0.4 cm. The probe beam for the transient absorption measurement was obtained from a 450-W Xe lamp, sent into the sample solution with a perpendicular intersection of the electron beam, and focused to a monochromator. The output of the monochromator was monitored by a photomultiplier tube (PMT). The signal from the PMT was recorded on a transient digitizer. The temperature of the sample solution was controlled by circulating thermostated aqueous ethanol around the quartz sample cell. Sample solution of M (5 x 10 -10 M) was prepared in a 1 x 1 cm rectangular Suprasil cell. 

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