Preferential oxidation of carbon monoxide in excess hydrogen over platinum catalysts supported on different-pore-sized mesoporous silica

Preferential oxidation (PROX) of carbon monoxide in excess hydrogen has been studied on low Pt loading (0.5–1 wt%) catalysts supported on a series of FSM-type mesoporous silica materials. A support effect has been observed, in which the catalytic activities are closely related with the pore diameter of the support, despite their similar specific surface areas. Pt nanoparticles supported on mesoporous silica with 4.0 nm pore diameter possess the highest CO conversion over a wide range of reaction temperature, i.e. ca. 100% CO conversion in 298–423 K. As a comparison, the Pt particles in small pore supports (1.8 nm) exhibit poor performance under the same reaction conditions, which is barely comparable to the Pt catalysts on amorphous silica. The discrepancy in the mesoporous silica is proposed to be related with the different activities of surface silanols in various supports.

Graphical abstractPreferential oxidation of carbon monoxide has been studied over low loading of Pt catalysts supported on FSM-type mesoporous silica materials with different pore diameters. Despite the same Pt loading (1 wt%) and similar specific surface areas (∼1000 m2 g−1), the catalysts exhibit different catalytic activities in the reaction. These results are informative for preparing lower Pt loading catalysts and for gaining more understanding of the catalytic role of mesoporous silica.Figure optionsDownload full-size imageDownload as PowerPoint slide