Zn-modified Co/N-C catalysts for adjustable conversion of 5-hydroxymethylfurfural to furan-based chemicals

5-Hydroxymethylfurfural (HMF) serves as a significant biomass platform molecule, and its selective conversion to produce furan-based chemicals is of great significance for biomass refining. Herein, a zinc-modified cobalt catalyst supported by nitrogen-carbon material (Zn1Co3/N-C) was prepared and showed an adjustable performance in the selective hydrogenation or hydrogenolysis of HMF to produce two important furan-based chemicals, 2,5-bis(hydroxymethyl)furan (BHMF) or 2,5-dimethylfuran (DMF). The catalyst's outstanding performance can be attributed to its ability to utilize a synergistic mechanism involving metal-acid interactions. This mechanism is achieved by introducing a second metal element (Zn), which in turn modifies the electronic structure of the initial metal surface and adjusts the acid content. By regulating the reaction temperature, the selectivity of 93.7% for BHMF or 93.5% for DMF were achieved with almost complete conversion of HMF. The results of catalyst characterization reveal that the Co metal sites and the ZnO acid sites play a key role in the hydrogenation of CO bonds and the hydrogenolysis of C-O bonds. This study unveiled the mechanism underlying the impact of both the acid quantity and the electronic structure of the metal surface on catalytic performance through the utilization of the zinc-modified catalyst's activity.