Influence of the support and the preparation methods on the performance in citral hydrogenation of Pt-based catalysts supported on carbon nanotubes

Pt-based catalysts supported on multi-wall carbon nanotubes were developed to study the influence of the support surface composition on the catalytic performance in the selective hydrogenation of citral to the corresponding unsaturated alcohols. Supports with different oxidative and thermal treatments were characterized and used to prepare Pt and PtFe catalysts. Three factors seem to be important to obtain an adequate catalytic phase: the size of the Pt metallic particles, the interaction of the Pt particles with the support, and the presence of a second metal as promoter. The results indicated that the Fe content in these catalysts and a low amount of oxygenated groups on the support surface, which produce an optimized Pt particle size, have a fundamental role over the selectivity of the reaction to unsaturated alcohols. In fact, the combination of these effects in the [Pt/CN]–N2700 catalyst gives a very high selectivity (about 96%) to unsaturated alcohols.