Mechanical Understanding of the Roles of Crystal Facets and the Aqueous Solution for the Hydrogenation of LGO to Cyrene with the Pd/Pt Catalysts

Abstract

Hydrogenation of biomass-derived levoglucosenone (LGO) into versatile dihydroleveglucosenone (Cyrene) is one of the most attractive biomass transformations due to its widespread application in chemical synthesis. LGO hydrogenation is commonly catalyzed by Pd/Pt catalysts, with the reaction being influenced by their crystal facets and reaction environment. Regrettably, the current understanding of the hydrogenation mechanism of LGO to Cyrene over these catalysts is limited. Herein, the catalytic hydrogenation mechanism of LGO to Cyrene on Pd/Pt catalysts was systematically studied based on the first principle calculations. Particularly, the roles of exposed crystal facets and the aqueous solution have been discussed. The hydrogenation of LGO begins with the absorption of its C═C bond, and the optimal pathways over Pd/Pt catalysts vary depending on different crystal facets. In addition, Pd(101) exhibits superior catalytic activity for LGO hydrogenation than that of Pt(111) when comparing the optimal facets of Pb and Pt catalysts (19.50 versus 185.05 kJ mol^⁻¹). H₂O chiefly affects the hydrogenation reactions by forming a hydrated derivative with LGO, altering the hydrogenation pathway for Cyrene production. This work can provide a theoretical basis for developing high-performance catalysts and exploring new ways to realize the efficient hydrogenation of LGO to Cyrene.