Selective Oxidation of Furfural to 2(5H)-Furanone and Maleic Acid over CuMoO4

Green synthesis of high-value furanone derivatives and C4 organic acids from renewable biomass is a promising yet challenging route. Herein, we report a suitable heterogeneous and recoverable bimetallic CuMoO4 catalyst for the selective oxidation of furfural to 2(5H)-furanone and maleic acid (MAc). The resulting CuMoO4 manifested excellent catalytic performance with a high furfural conversion of 99%, giving a 2(5H)-furanone yield of up to 66% or a MAc yield of over 74% by regulating the reaction conditions. The synergy of Cu and Mo species in CuMoO4 boosted the outstanding catalytic efficiency through the Mo6+–Mo5+–Mo4+ redox facilitated by the redox of Cu+/Cu2+. More importantly, the Mo species in CuMoO4 played a key role in activating the aldehyde group in furfural to facilitate hydrogen abstraction from the aldehyde group by CuMoO4 and the active SO4•– radical, which was from peroxymonosulfate (PMS). This work presents a sustainable process for the fabrication of bio-based polymer precursors and offers a bifunctional catalysis strategy for efficient oxidation.