Understanding the reaction route of selectively converting furfural to furan over the alkali-induced Co-Mo2C heterostructure

Using furfural (FA) as raw material to produce furan (FF) seems to be an efficient and sustainable strategy. Herein, a catalyst (Co-Mo2C/CN) with Co-Mo2C heterostructure prepared by in-situ modulation of the molybdenum phase with NaOH was applied in the conversion of FA to FF. The heterostructure brought an enhanced electron transfer from Co to Mo2C, which promoted the hydrogen dissociation over the Co sites. It gave 72.21% yield of furan at optimum conditions (180 °C and 2 MPa). According to the kinetic study, we proposed a unique reaction route for FA conversion to FF. Firstly, FA is hydrogenated to furfural alcohol, then furfural alcohol is hydrodeoxygenated to 2-methylfuran, finally FF is obtained via demethylation (rate-determined step). Furthermore, the selective adsorption of various substrates (via in situ FT-IR) over the Co-Mo2C/CN catalyst resulted in high selectivity to furan. This study not only provides a feasible strategy to construct non-noble metal heterostructure, but also gives a deep understanding of the reaction process of converting furfural to furan over the non-noble metal catalyst.