A series of highly crystalline, porous, zirconium-based metal-organic frameworks (Zr-MOFs) with different ligand functionality and porosity were applied for catalytic transfer hydrogenation of ethyl levulinate (EL) to form γ-valerolactone (GVL), using isopropanol as a hydrogen donor. The role of ligand functionality and the metal center of the Zr-MOFs were identified and reaction parameters were optimized, for selective production of GVL. Maximum yield of GVL (up to 92.7%) was achieved in 2 h at 200 o 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/min) among the catalysts tested at 130 o C. It was also found 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 notable change in catalytic activity and product selectivity. Fresh and recycled catalysts were characterized in detail using X-ray diffraction (XRD), N2 adsorption-desorption, thermal gravimetric 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.

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Adsorption-driven heat transfer devices incorporating an efficient “adsorbent–water” working pair are attracting great attention as a green and sustainable technology to address the huge global energy demands for cooling and heating. Herein, we report the improved heat transfer performance of a defective Zr fumarate metal–organic framework (MOF) prepared in a water solvent (Zr-Fum HT). This material exhibits an S-shaped water sorption isotherm (P/P 0 = 0.05–0.2), excellent working capacity (0.497 mLH2O mL–1 MOF) under adsorption-driven cooling/chiller working conditions (T adsorption(ads) = 30 °C, T condensation (con) = 30 °C, and T desorption(des) = 80 °C), very high coefficient of performances for both cooling (0.83) and heating (1.76) together with a relatively low driving temperature at 80 °C, a remarkable heat storage capacity (423.6 kW h m–3 MOF), and an outstanding evaporation heat (343.8 kW h m–3 MOF). The level of performance of the resultant Zr-Fum HT MOF is above those of all existing benchmark water adsorbents including MOF-801 previously synthesized in the N,N-dimethylformamide solvent under regeneration at 80 °C which is accessible from the solar source. This is coupled with many other decisive advantages including green synthesis and high proven chemical and mechanical robustness. The microscopic water adsorption mechanism of Zr-Fum HT at the origin of its excellent water adsorption performance was further explored computationally based on the construction of an atomistic defective model online with the experimental data gained from a subtle combination of characterization techniques.