No abstract

X-ray photoelectron spectroscopy has been used to investigate the composition of both the surface of DeNO, catalysts (Ti: Mo: V = 92 : 6 : 2 and Ti : W : V = 85 : 10: 5 at.%) and the material deposited from the flue gas. In spite of the charging of the surface in the spectrometer, it was possible to perform both qualitative and quantitative analysis. The deposits primarily contain Ca, Si, 0, S, As, P and N. Oxidation numbers of Ca, Si, Ti, Mo, W, S and N were determined from chemical shifts in combination with line widths. There are, however, problems with the determination of the oxidation state of As owing to an influence of the exciting Al Ka radiation on the oxidation state. Nevertheless, As seems to exist both as As3+ and As5+.