Calcium decorated Copper@Nitrogen-Doped carbon towards highly selective hydrogenation of biomass derived furfural

Abstract

In the present research, calcium decorated copper@nitrogen-doped carbon (marked as Cu1Cax@CN) derived from biomass was constructed for highly selective hydrogenation of bio-based furfural (FFR), which remarkably favored furan ring hydrogenation for tetrahydrofurfuryl alcohol (THFA) formation via regulating the hydrogenation path. Remarkably, the in-situ generated basic sites from N- and Ca-containing species were beneficial to the good metal dispersion as well as the chemical activation of aldehyde and C=C groups, thus favoring the FFR-to-THFA transformation. The optimal basic density-to-copper mass ratio in a range of 3.0 ∼ 4.0 was attained, in consideration of THFA generation. The as-prepared Cu1Ca0.87@CN catalyst could afford full FFR conversion as well as 75.6 % THFA yield under 3 MPa H2 atmosphere, which also exhibited excellent stability and could be recycled four times without any deactivation. In addition, the basic sites in the as-prepared Cu1Cax@CN samples were capable of activating both the C=O and C=C bonds, and the activation of C=O bond took precedence over that of C=C bond, especially in the case of relative low temperatures. Plausible reaction mechanism for FFR-to-THFA transformation under the synergistic effect of active Cu0 center and basic sites was proposed in detail.