Revealing the inhibitory reduction effect of Zr species on CoO to enhance the stability for furfural hydrogenolysis to 2-methylfuran

Abstract

High selective hydrogenolysis of furfural to 2-methylfuran over a metal oxide-based catalyst is promising and challenging. In this paper, a Zr-modified CoO_x (Zr₁Co₆-325) catalyst was prepared via a simple co-precipitation/reduction and exhibited superior initial activity and remarkable circular stability during the hydrogenolysis of furfural (FUR) to 2-methylfuran (2-MF). As high as 71.2 % yield of 2-MF was achieved at 170 °C for 2 h and nearly no deactivation was found after five cycles, much better than those of reduced Co₃O₄ catalyst (Co₃O₄-250). Comprehensive studies demonstrated that the over-reduction of the CoO species during the reaction process was the main cause of catalyst deactivation. The introduction of Zr species, on the one hand, inhibited the over-reduction of CoO species during reaction processes, thereby enhancing the circular stability. On the other hand, the introduction of Zr species promoted the activation and dissociation of H₂ and therefore improved the activity. This research unveiled the stabilizing effect of Zr species on CoO, providing guidance for the design of high-stable CoO-based catalysts.