Heterogeneous graphene oxide (GO)-based catalysts with sulfonic acid (SO₃H) functional groups (GO–SO₃H) were used for the selective decomposition of the hexose sugars, glucose and fructose into levulinic acid (LA), which has been used as a platform chemical for various value-added derivatives. The GO–SO₃H catalysts gave high yields of around 78% for LA and showed good reuse compatibility with reliable performance. The chemical transformation patterns for hexose sugar decompositions are affected by the temperature, the density of acid sites, and the type of catalyst. The high catalytic performance of GO–SO₃H was shown to result from the higher density of Brønsted acid sites in the GO, compared with the Lewis acid sites in other AC–SO₃H catalysts. The morphology, surface characteristics, and other physiochemical properties were evaluated using several characterization techniques.

A series of highly crystalline, porous, zirconium-based metal–organic frameworks (Zr-MOFs) with different ligand functionalities and porosities were applied for catalytic transfer hydrogenation of ethyl levulinate (EL) to form γ-valerolactone (GVL), using isopropanol as a hydrogen donor. The roles of the ligand functionality and the metal center of the Zr-MOFs were identified and reaction parameters optimized, for selective production of GVL. The maximum yield of GVL (up to 92.7%) was achieved in 2 h at 200 °C with UiO-66(Zr). Interestingly, zirconium trimesate (MOF-808) emerged as the most suitable candidate, with the highest GVL formation rate (94.4 μmol g⁻¹ min⁻¹) among the catalysts tested at 130 °C. It was also found to be effective in conversion of EL to GVL in an open system using the solvent refluxing method. Both the catalysts (UiO-66(Zr) and MOF-808) were recycled at least five times under their specified reaction conditions without a notable change in catalytic activity and product selectivity. Fresh and recycled catalysts were characterized in detail using X-ray powder diffraction (XRD), N₂ adsorption–desorption, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) in order to understand the stability and structural changes that occurred in the catalysts. Finally, a plausible reaction mechanism was presented on the basis of active sites present in catalysts confirmed by characterization results.

We present facile route for the shaping of MOFs (MIL-100(Fe), MIL-101(Cr), UiO-66(Zr), and UiO-66(Zr)_NH₂) using mesoporous ρ-alumina (MRA) as a binder.