Mesoporous sulfur-decorated Pt-Al2O3 for dehydrogenation of perhydro benzyltoluenes: Activity-favorable adsorption of reaction species onto electron-deficient Pt atoms

The addition of sulfur to supported Pt catalysts often regulates Pt defect sites causing side reactions, where the interaction between Pt and sulfur depends on catalyst preparation methods. Herein, we report the solvent-deficient precipitation (SDP) to afford mesoporous sulfur-decorated Pt-Al2O3 catalysts with different sulfur contents. In the dehydrogenation of perhydro benzyltoluenes, the degree of dehydrogenation shows the volcano-shaped dependence on the sulfur content at the maximum with 0.21 wt% sulfur. The best performance catalyst is robust in recycle runs owing to negligible Pt growth and sulfur loss. The sulfur added lowers the electron density of Pt atoms because of the favorable contact between Pt and sulfur species by the SDP method compared to the conventional impregnation. The electron-deficient Pt atoms weaken the adsorption of aromatic products and induce appropriate H-2 adsorption. Thus, the titled catalyst is tolerant to the dehydrogenation products and less selective to the side product methylfluorene. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

The addition of sulfur to supported Pt catalysts has an impact on Pt defect sites and side reactions, which is influenced by the catalyst preparation methods. In this study, mesoporous sulfur-decorated Pt-Al2O3 catalysts with different sulfur contents were prepared using the solvent-deficient precipitation (SDP) method. The dehydrogenation of perhydro benzyltoluenes showed a volcano-shaped dependence on the sulfur content, with the maximum dehydrogenation achieved at 0.21 wt% sulfur. The best performing catalyst exhibited excellent recyclability due to negligible Pt growth and sulfur loss. The SDP method facilitated favorable contact between Pt and sulfur species, resulting in a reduction in electron density of Pt atoms. This electron-deficient Pt atoms weakened the adsorption of aromatic products and facilitated appropriate H-2 adsorption. As a result, the titled catalyst exhibited tolerance towards dehydrogenation products and lower selectivity towards the side product methylfluorene.