Metal-Organic Frameworks in Germany: from Synthesis to Function

Metal-organic frameworks (MOFs) are constructed from a combination of inorganic and organic units to produce materials which display high porosity, among other unique and exciting properties. MOFs have shown promise in many wide-ranging applications, such as catalysis and gas separations. In this review, we highlight MOF research conducted by Germany-based research groups. Specifically, we feature approaches for the synthesis of new MOFs, high-throughput MOF production, advanced characterization methods and examples of advanced functions and properties

Adsorption Refrigeration Technologies

This chapter introduces a comprehensive overview about the principles, challenges and applications of adsorption refrigeration systems (ARSs), as a promising sustainable solution for many of cooling and heating applications. In addition to the features and the basics of ARSs, the following topics have been covered such as characteristics of working pairs, trends in improving the heat and mass transfer of the adsorber; advanced adsorption cycles and performance and operational data of some adsorption refrigeration applications. In some details, the operating range and the performance of ARSs are greatly affected by the employed working adsorbent/refrigerant pairs. Therefore, the study, development and optimum selection of adsorbent/refrigerant pairs, particularly the composite adsorbents, can lead to improving the performance and reliability of ARSs. Regarding the enhancement of heat and mass transfer in the adsorbent bed, two methods are commonly used: one is the development of adsorbents through different coating technologies or new materials such as metal-organic frameworks, and the second is the optimization of the adsorber geometrical parameters and cycle modes. Finally, a brief on some adsorption chillers applications have started to find their share in markets and driven by solar or waste heats

Numerical and experimental evaluation of advanced metal-organic framework materials for adsorption heat pumps

In this study the potential of a number of metal-organic framework materials namely; MIL-101(Cr), MIL-100(Fe), CP0-27(Ni) and aluminium fumarate was investigated in various adsorption applications such as heat pump, water desalination and heat storage. The properties of MIL-101(Cr) in terms of thermal conductivity and water vapour capacity were further improved through synthesizing novel composites with graphene oxide (GrO) and calcium chloride (CaCl$_2$). Also, the adsorption isotherm shape and capacity of MIL-100(Fe) were tuned through synthesizing two core-shell mechanism composites. The core-shell composites of MIL-101(Cr)/MIL-101(Fe) and CP0-27(Ni)/MIL 100(Fe) were synthesized to use the advantage of the high-water vapour uptake of MIL-101(Cr) in the high relative pressure and of CP0-27(Ni) in the low relative pressure range. Also, integrating the MOF material as a coated layer instead of the granular form was investigated as an alternative for conventional packed adsorption beds. MIL-100(Fe) and aluminium fumarate were chosen to be experimentally tested in a two-bed adsorption system. The effect of various operating conditions such as chilled water inlet temperature, cycle time, adsorption bed cooling water inlet temperature, desorption bed heating water inlet temperature and condenser cooling water inlet temperature was investigated

Green Preparation of Aluminum-based Metal-organic Framework (Al-MOF) from Waste Plastic Bottles and Waste Aluminum Scraps

The vast use of polyethylene terephthalate (PET) drinking water bottles has increased dramatically worldwide in recent decades, inflicting severe consequences on the environment. According to the latest survey, a million plastic bottles are bought around the globe every minute. The non-biodegradable nature of PET materials has led to a huge accumulation of plastic in waste landfills. Among the current recycling methods used to solve this environmental problem is chemical recycling. In this method, PET bottles are converted back cleanly into their starting materials: terephthalic acid and ethylene glycol. This paper unveils the exploitation of recycling products from PET bottles and aluminium scraps in order to prepare a metal-organic framework (MOF) material. The characterization of the prepared MOF substance was carried out using different techniques such as IR, XRD, SEM and elemental analysis.                 &nbsp

Alcohol-Based Adsorption Heat Pumps using Hydrophobic Metal-Organic Frameworks

The building climate industry and its influence on energy consumption have consequences on the environment due to the emission of greenhouse gasses. Improving the efficiency of this sector is essential to reduce the effect on climate change. In recent years, the interest in porous materials in applications such as heat pumps has increased for their promising potential. To assess the performance of adsorption heat pumps and cooling systems, here we discuss a multistep approach based on the processing of adsorption data combined with a thermodynamic model. The process provides properties of interest, such as the coefficient of performance, the working capacity, the specific heat or cooling effect, or the released heat upon adsorption and desorption cycles, and it also has the advantage of identifying the optimal conditions for each adsorbent-fluid pair. To test this method, we select several metal-organic frameworks that differ in topology, chemical composition, and pore size, which we validate with available experiments. Adsorption equilibrium curves were calculated using molecular simulations to describe the adsorption mechanisms of methanol and ethanol as working fluids in the selected adsorbents. Then, using a thermodynamic model we calculate the energetic properties combined with iterative algorithms that simultaneously vary all the required working conditions. We discuss the strong influence of operating temperatures on the performance of heat pump devices. Our findings point to the highly hydrophobic metal azolate framework MAF-6 as a very good candidate for heating and cooling applications for its high working capacity and excellent energy efficiency

Towards high CO2 conversions using Cu/Zn catalysts supported on aluminum fumarate metal-organic framework for methanol synthesis

SUPPLEMENTARY MATERIAL : FIGURE S1: Individual elemental maps of 7Cu/3Zn/AlFum MOF. (a) Al K 1; (b) Cu K 1; and (c) Zn K 1; FIGURE S2: Individual elemental maps of 15Cu/6.4Zn/AlFum MOF. (a) Al K 1; (b) Cu K 1; and (c) Zn K 1; FIGURE S3: Derivative TGA plot of AlFum MOF. FIGURE S4: Derivative TGA plot of 7Cu/3ZnO/AlFum MOF; FIGURE S5: Derivative TGA plot of 15Cu/6.4ZnO/AlFum MOF.Green methanol is a viable alternative for the storage of hydrogen and may be produced from captured anthropogenic sources of carbon dioxide. The latter was hydrogenated over Cu-ZnO catalysts supported on an aluminum fumarate metal-organic framework (AlFum MOF). The catalysts, prepared via slurry phase impregnation, were assessed for thermocatalytic hydrogenation of CO2 to methanol. PXRD, FTIR, and SBET exhibited a decrease in crystallinity of the AlFum MOF support after impregnation with Cu-Zn active sites. SEM, SEM-EDS, and TEM revealed that the morphology of the support is preserved after metal loading, where H2-TPR confirmed the presence of active sites for hydrogen uptake. The catalysts exhibited good activity, with a doubling in Cu and Zn loading over the AlFum MOF, resulting in a 4-fold increase in CO2 conversions from 10.8% to 45.6% and an increase in methanol productivity from 34.4 to 56.5 gMeOH/Kgcat/h. The catalysts exhibited comparatively high CO selectivity and high yields of H2O, thereby favoring the reverse water-gas shift reaction. The selectivity of the catalysts towards methanol was found to be 12.9% and 6.9%. The performance of the catalyst supported on AlFum MOF further highlights the potential use of MOFs as supports in the heterogeneous thermocatalytic conversion of CO2 to value-added products.The Royal Society- Foreign, Commonwealth & Development Office (FCDO) Africa Capacity Building Initiative (ACBI) Programme, the Council for Scientific and Industrial Research (CSIR), the South African Department of Science and Innovation (DSI) for research activities under HySA Infrastructure and the South Africa—France PROTEA Programme..https://www.mdpi.com/journal/catalystsam2023Chemistr