Catalytic insights into perhydro-benzyltoluene dehydrogenation: Probing surface characteristics revealed by DRIFTS study.

The enhancement of dehydrogenation activity in liquid organic hydrogen carriers (LOHC), such as perhydro-benzyltoluene (H 12 -BT), has been attributed to the addition of various promoters and support modifications into platinum (Pt)-based heterogeneous catalysts. Comprehensive understanding of surface sites predominantly catalyzing the dehydrogenation process is crucial for further enhancing catalytic performance. In this contribution, an in-depth quantitative CO diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFTS) study on Pt-based catalysts with varying contents of sulfur, known to be effective in dehydrogenation reactions, is performed to unveil the active sites involved in the H 12 -BT dehydrogenation. Furthermore, while challenges associated with the adsorption step of reactants and products potentially deteriorate catalytic activity, these processes remain open questions for H 12 -BT dehydrogenation. To shed light on these aspects, we conducted in situ DRIFTS experiments utilizing H 12 -BT and H 0 -BT, its dehydrogenated counterpart, to determine the adsorption strength between these molecules and the different catalyst surfaces, influenced by the electron-deficiency effect due to the addition of sulfur. Additionally, our study investigates the correlation between sulfur-induced catalyst surface characteristics and the formation of methane through the demethylation process. [Display omitted] • Sulfur deposition increases metal dispersion by altering the particle distribution across the catalyst beads. • At a sulfur content of 0.13 wt%, the degree of dehydrogenation reaches 97 % over 50 h. • CO-DRIFTS suggest a rigorous correlation between dehydrogenation activity and the density of step Pt sites. • Sulfur addition boosts perhydro-benzyltoluene adsorption while suppressing benzyltoluene adsorption. • Demethylation reaction is restricted as sulfur loading increases due to the decline in strong Lewis acidic sites. [ABSTRACT FROM AUTHOR]