One-step efficient non-hydrogen conversion of cellulose into γ-valerolactone over AgPW/CoNi@NG composite

One-step efficient conversion of cellulose into value-added γ-valerolactone (GVL) is of great interest because it not only integrates complex tandem reactions in one-step, but also does not need additional hydrogen sources. To achieve this goal, it is crucial to fabricate high-performance catalyst that can accelerate both hydrolysis of cellulose and further transformation of generated stoichiometric levulinic acid (LA) and formic acid (FA) into GVL. CoNi nanoparticles encapsulated in N-doped thin graphene shell gave GVL yield as high as 55.9 % at 200 °C combined with Ag+-exchanged heteropolyacid (AgPW). This composite catalyst is highly resistant to the corrosion of LA and FA, and hence shows high catalytic stability. LA-adsorption FTIR spectra and DFT calculations indicate that LA and FA can penetrate through shell graphene layers into core CoNi sites via cracks. Compared to H2, FA can much more rapidly reduce LA because of its low dissociation energy barrier and high dissociation rate.