Synthesis of carbon–titania composite and its application as catalyst support

We reported the synthesis of a promising carbon–titania composite material, C/TiO2, and its application as the catalyst support in citral hydrogenation. The composite was synthesized by methane decomposition over formed TiO2 using Ni–Cu as a catalyst. C/TiO2 synthesized was subsequently employed to prepare its supported palladium catalyst, Pd/C/TiO2. The textural and structural properties of C/TiO2 and Pd/C/TiO2 were characterized by BET, SEM/EDS, TEM, ICP-AES, XRD and TG-DTG. The catalytic properties of Pd/C/TiO2 were evaluated in selective hydrogenation of citral to citronellal. Results revealed that the addition of a little promoter Cu in composite synthesis helped to the improvement in textural and structural properties of C/TiO2. The optimal composite prepared had a BET surface area of 60 m2 g−1 and 97% of its pore space were mesopore. It contained 38% of carbon composed of 90% of carbon nanofibers and 10% of amorphous carbon. Pd/C/TiO2 prepared held the similar textural and structural properties as C/TiO2 did. Although the comparatively lower catalytic activity caused by the lower palladium dispersion, Pd/C/TiO2 exhibited the high citronellal selectivity (90%) at 90% citral conversion, which was attributed to the elimination of internal diffusion limitations due to its mesoporous structure.

Graphical abstractSEM images of the carbon-titania composite (the surface and the cross section of the material, respectively).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► C/TiO2 composite was prepared by methane decomposition over formed TiO2. ► C/TiO2 contained 38% of carbon composed of CNFs (90%) and amorphous carbon (10%) ► 97% of the pore space in Pd/C/TiO2 catalyst was mesopore ► Pd/C/TiO2 catalyst exhibited high selectivity to citronellal in citral hydrogenation.