Synthesis of spherical-like Pt–MCM-41 meso-materials with high catalytic performance for hydrogenation of nitrobenzene

Spherical-like Pt–MCM-41 meso-materials, including Pt–MCM-41, Pt–Al–MCM-41, and Pt–La–MCM-41, as well as MCM-41, were synthesized by a “one-step” approach with orthosilicate (TEOS) as silica source and cetyltrimethylammonium bromide (CTAB) as a template in the presence of suitable H2SO4 (or HCl) at 0 °C. The samples were characterized by XRD, N2 sorption, FTIR, SEM, TEM, ICP-AES, and XPS techniques. The results show that the metallic cations (such as Al3+ and La3+) were hard to be incorporated into the synthesized samples under strong acidic conditions. However, H2PtCl6 can be introduced almost 100% in the as-synthesized Pt-containing meso-materials, and H2PtCl6 in the samples can be decomposed mostly into metallic Pt accompanied by part Pt2Si and few Pt oxides during the calcination at 550 °C to remove the template. In the catalytic hydrogenation of nitrobenzene, the calcined Pt–MCM-41 meso-materials, like the corresponding reduced samples, exhibit high catalytic activities with an excellent selectivity to aniline, which are much better than those of the reduced Pt/MCM-41 prepared by the incipient wetness method.

Pt–MCM-41 synthesized in the presence of H2SO4 (or HCl) at 0 °C has spherical-like morphology. TEM image of as-synthesized Pt–MCM-41 indicates that it is composed of spherical-like particles with different nano-sizes.Figure optionsDownload high-quality image (65 K)Download as PowerPoint slide