THIOPHENE ADSORPTION STUDIES ON CLEAN AND HYDROGEN-PREADSORBED MOS2(100) SURFACE

It is known from temperature-programmed desorption studies that the bi nding energy of thiophene over Mo/gamma-Al2O3 and Co-Mo/gamma-Al2O3, h ydrodesulfurization catalysts, is lower in the presence of hydrogen. T he adsorption of thiophene on clean and hydrogen-adsorbed MoS2 was mod elled using extended Huckel tight binding band structure calculations. In the eta(1) adsorption configuration the calculations show a lower binding energy for adsorption on the hydrogen-preadsorbed surface simi lar to that observed experimentally. The lowering is due to an increas ed occupancy of the Mo density of states in the presence of hydrogen.