Carbon Formation and Active Site of Alumina Supported Platinum Catalyst in Steam Methane Reforming Containing Sulfur

Effect of sulfur poisoning on Pt/α-Al2O3 catalysts in steam methane reforming (SMR) was investigated using dimethyl sulfide (DMS). SMR with and without 10 ppm DMS addition was performed over 0.1-2.0 wt% Pt/α-Al2O3 catalysts. Catalyst deterioration occurred at an early stage, but not inactivation in the presence of DMS. Moreover, after the supply of DMS was stopped, the activity was completely restored. DMS in the reaction gas also caused severe sintering of the Pt particles and promoted carbon formation on the 1.0-2.0 wt% Pt catalysts. On the other hand, carbon formation did not occur on the 0.1 wt% Pt catalysts. The Pt sintering and carbon formation behaviors were independent of the SMR activity. These results suggest that three different active sites are formed on the Pt/α-Al2O3. The first is a SMR active site not affected by DMS. The second is an active site that loses activity due to DMS, but completely regenerates after the supply of DMS is stopped. The third is not an active site of SMR but where sintered Pt accelerates methane decomposition to produce carbon.