Support effect in the hydrodesulfurization of thiophene over rhodium sulfide

The effect of support on thiophene hydrodesulfurization activity over rhodium sulfide was studied. The loading was 5 wt% and the supports were (surface areas S BET in m2 g−1 in parenthesis): C (1100), Nb2O5 (99), ZrO2 (108), TiO2 (140), SiO2 (289), MgO (300) and 11 Al2O3 (77–279). The activity at 400 °C decreased in the order (relative activity in parenthesis): C (4.44), Al2O3 (0.98–0.32), Nb2O5 (0.54), ZrO2 (0.50), TiO2 (0.48), SiO2 (0.26), MgO (0.19), commercial CoMo/Al2O3 (1.00). The activity did not correlate with S BET, point of zero charge PZC of the support and the ratio S/Rh in the presulfided catalysts. The broad range of activities of Rh/Al2O3 illustrate that secondary factors such as S BET, texture, PZC, impurities and additives might be as important as the principal type of the support.