화학공학소재연구정보센터
Catalysis Letters, Vol.53, No.3-4, 193-198, 1998
Modification of the alumina-supported Mo-based hydrodesulfurization catalysts by tungsten
The incorporation effect of tungsten as an activity-promotional modifier into the Ni-promoted Mo/gamma-Al2O3 catalyst was studied. Series of W-incorporated catalysts with different content of tungsten were prepared by changing the impregnation order of nickel and tungsten onto a base Mo/gamma-Al2O3. Catalytic activities were measured from the atmospheric reactions of thiophene hydrodesulfurization (HDS) and ethylene hydrogenation (HYD). The HDS and HYD activities of the WMo/gamma-Al2O3 catalysts (WM series) initially increased and subsequently decreased with increasing content of tungsten as compared with those of their base Mo/gamma-Al2O3. The maximal activity promotion occurred at the W/(W + Mo) atomic ratio 0.025. For the Ni-promoted Mo/gamma-Al2O3 catalysts, the effect of W incorporation was greatly dependent on the impregnation order of tungsten. The catalysts prepared by impregnating Ni onto the WMo/gamma-Al2O3 catalysts showed the same trend of activity promotion as for the WM series, while those by impregnating W onto a NiMo/gamma-Al2O3 catalyst resulted in lower activities than their base NiMo/gamma-Al2O3 catalyst. To characterize the catalysts, temperature-programmed reduction and low-temperature oxygen chemisorption were conducted. The effects of W incorporation on the NiMo-based catalysts were discussed in reference to those on the CoMo-based catalysts.