Enhanced activity of a WOx-incorporated Pt/Al2O3 catalyst for the dehydrogenation of homocyclic LOHCs: Effects of impregnation sequence on Pt–WOx interactions

Abstract

This study focused on the development of catalysts for the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT) and perhydro-benzyltoluene (H12-BT), which are promising liquid organic hydrogen carriers (LOHCs). The reaction was performed at a low temperature to ensure hydrogen purity and catalyst durability, and the incorporation of WOx into Pt/Al2O3 was investigated to improve the low-temperature activity of the Pt/Al2O3 catalyst. WOx-incorporated Pt/Al2O3 catalysts with superior performance compared to that of the Pt/Al2O3 catalyst were developed by controlling the amount of incorporated WOx and the impregnation sequence of metals during catalyst preparation. TEM, chemisorption, and XPS analyses assisted in confirming the changes in the structure and electron density of the active material in accordance with the impregnation sequence and the amount of incorporated WOx; moreover, these factors were found to influence the catalyst performance. The electron-donating ability of W was determined according to the impregnation sequence of the metals, and confirmed by XPS analysis and the experimental reaction results. A DFT study on a hypothetical model containing WOx confirmed the donation of electrons from W to Pt, which was consistent with the experimental results. In addition, the H12-BT dehydrogenation on the investigated catalyst was kinetically more favorable compared to that on the Pt/Al2O3 catalyst, resulting in an enhancement of the dehydrogenation activity.