Abstract
The effect of UV illumination on the stability of Rh dicarbonyl on TiO2 and on the surface interaction of NO + CO gas mixture on TiO2 and Rh/TiO2 catalysts was examined with FTIR spectroscopy. Photolysis of Rh1(CO)2 over TiO2 caused the decomposition of this complex, and the formation of Rhx–CO and Rh2(CO)3 surface compounds. Illumination of the NO + CO/TiO2 system at 200 K produced a new band at 2212 cm−1, which is attributed to the Ti–NCO species. This species is not observed in the absence of illumination even after extended adsorption time. Coadsorption of NO + CO gas mixture on Rh/TiO2 gave an absorption band at 2160–2175 cm−1, not detected after adsorption of NO and CO separately. This band is assigned to the vibration of NCO bonded to the Rh. UV illumination dramatically enhanced the surface concentration of Rh–NCO surface species at both 200 and 300 K. It is assumed that the extent of the electron transfer from TiO2 to the Rh is enhanced due to the photoelectrons which leads to the greater probability of the surface dissociation of NO, the key step in the formation of NCO surface complex.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have