LAUSR

The present study focuses on developing a stable basic MnOx support for Ru (RuMn) for the efficient oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) in water in the absence of an external base. A series of MnOx support, synthesized via hydrothermal approach using urea as precipitant, is prepared by thermally treating at various temperatures (300 - 800 °C) before doping Ru. The RuMn-2 (1wt% Ru, MnOx calcined at 400 °C), possesses a large number of basic sites (1.72 mmol/g) based on CO 2 -TPD analysis, affording an FDCA yield of 87% with TOF of 22 h -1 . TEM-EDX elemental mapping of RuMn-2 shows a high dispersion of Ru over the surface of MnOx, contributing to the efficient HMF oxidation. Moreover, XRD, XPS, and H 2 -TPR analyses indicate that the predominant MnO 2 phase (ε-MnO 2 ) plays a vital role in HMF oxidation. The RuMn-2 is recyclable for up to four runs without significant loss in the activity and retains its structural integrity.