Regulation of Pt Loading on Co/Al₂O₃ Catalysts for Selective Hydrogenation and Hydrogenolysis of 5-Hydroxymethylfurfural to 2,5-Bis(hydroxymethyl)furan and 2,5-Dimethylfuran

Selective hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-dimethylfuran (DMF) were explored by regulating the nanosized Pt on Co/Al2O3 catalysts. Characterization results revealed that the catalyst acidity was influenced by adjusting the Co/Pt composition, while the addition of more Pt loading on Co/Al2O3 catalysts resulted in a facilitation of H-2 reduction process. Lower size of catalyst particles was obtained for the Co-Pt system in comparison to the monometallic Co/Al2O3 catalyst. Additionally, the structural characterizations by XRD, XANES, and XPS established the co-existences between metallic Pt0/Co0 and oxophilic PtO2/CoOx, acting as the active components for the reactions. Operated under a full HMF conversion, the Co1Pt0.050Al catalyst with high Pt loading gave >99.9 % BHMF selectivity at 40 C-degrees; whereas, an 86.7 % of DMF selectivity was noticeable over low Pt loading of the Co1Pt(0.013)Al catalyst at 160 C-degrees. This investigation evidenced that the selective production of BHMF or DMF towards hydro-conversion of HMF was relied on the amount of Pt contents on Co/Al2O3 catalyst, in which the metal sizes and acidity had meaningful effects on the hydrogenation and hydrogenolysis processes.