Understanding the promotional effects of trace doped Zn in Co/NC for efficient one-pot catalytic conversion of furfural to 2-methyl-tetrahydrofuran

Abstract

2-methyl-tetrahydrofuran (2-MTHF) is a promising biofuel or fuel additive with excellent burning property, a versatile new-style solvent in organic synthesis, and an important medical intermediate. In this work, a one-pot selective conversion of furfural (FA) into 2-MTHF was carried out over Zn doped Co/NC catalysts. The Zn-Co/NC-1 catalyst with trace Zn dopant (0.38 wt%) exhibited the best performance (yield of 2-MTHF: 93.8%). According to the characterizations, it was found that the Zn not only incorporates into the carbon support but also partially dopes into Co nanoparticles. Subsequently, theoretical calculations demonstrated that the doping of Zn in carbon support can effectively enhance the electron transfer from the support to the metallic Co particle, leading to the electron-rich Co surface. The presence of Zn was found to promote the dissociation of hydrogen and to lower the diffusion barrier of hydrogen atom, in favor of the hydrogenation/hydrodeoxygenation processes. Furthermore, the Zn doped models exhibit much lower barrier in breaking C–OH bond of FOL, resulting in higher activity for hydrodeoxygenation of FOL. These theoretical results are consistent with the in situ FT-IR analysis of adsorption substrates and intermediates over Zn doped catalyst. This work reveals the mechanism of dopant Zn tailoring the electronic structure and catalytic performance of active sites, providing a deep insight into the design of economical and high-performance catalysts for hydrogenation/hydrodeoxygenation of biomass feedstocks.