https://cris.library.msu.ac.zw//handle/11408/298 Sat, 11 Apr 2026 10:16:41 GMT 2026-04-11T10:16:41Z https://cris.library.msu.ac.zw//handle/11408/6852 Title: Crystal engineering of robust metal-organic frameworks for applications in capture of carbon dioxide Authors: Gudyanga, Ishekudzwai Blessed Abstract: The atmospheric concentration of carbon dioxide gas (CO2) is of global concern given its continued rise. Burning of fossil fuel has increased since the beginning of the industrial revolution, which then increased the atmospheric CO2 concentration to > 400 ppm from 280 ppm. CO2 has an effect of trapping the sun’s heat, and is believed to be one of the cardinal contributors of global warming. In order to make improvements to the CO2 problem, carbon capture techniques have been proposed. MOFs are porous structures constructed from the coordinative bonding between metal ions and organic linkers or bridging ligands. Thus, having an enormous choices of metal clusters and organic linkers, MOFs possess a wide range of surface area, pore volume and functionality, and this has contributed to the consideration of them being versatile materials for storage, separation, and catalysis, etc. Therefore, there is need to synthesise MOFs which capture CO2 and convert it into useful chemicals such as methanol and formic acid for industrial application. Linker 2,2’-bipyridine-5,5’ dicarboxylic acid and ceric metal salt Ce(NO3)3·6H2O were used in this study. Two MOFs were synthesised by solvothermal method. These were characterised by TGA, PXRD, FTIR, Potentiostat Galvanostat and Gas Sorption. The two MOFs MSU-3 and MSU-4 were thermally and chemically stable. The thermal and chemical stability observed in the MOFs emanated from the presence of the rod secondary building unit, which are linked by the pyridyl carboxylate linker to give three dimensional structures. CO2 adsorption studies of the MOFs revealed a low uptake of the gas in comparison to those MOFs reported literature. MSU-3a and MSU-4a was tested for electroactivity. Also, resistivity was tested using electrical impedance spectroscopy. It was found out that both MOFs had a lower interfacial electron transfer resistance. Sun, 01 Jan 2023 00:00:00 GMT https://cris.library.msu.ac.zw//handle/11408/6852 2023-01-01T00:00:00Z Gudyanga, Ishekudzwai Blessed https://cris.library.msu.ac.zw//handle/11408/6625 Title: Copper-based metal-organic framework: synthesis, characterization and evaluation for the hydrogenation of furfural to furfuryl alcohol Authors: Moyo, Pamela S.; Mehlana, Gift; Matsinha Leah C.; Makhubela Banothile C. E. Abstract: A novel Cu-MOF was synthesized at room temperature from commercially available and inexpensive reagents. The pre-catalyst was characterized using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, inductively coupled plasma-optical emission spectroscopy, Fourier transform-infrared spectroscopy, powder X-ray diffraction, Brunauer-Emmet-Teller (BET) and scanning electron microscopy-energy dispersive X-ray spectroscopy. The Cu-MOF was characterized as microporous material with BET surface area and pore volume of 7.47 m2/g and 0.27 cm3/g, respectively, and is stable in most solvents. The MOF was evaluated as a heterogeneous catalyst for the hydrogenation of furfural to furfuryl alcohol (FA). Cu-MOF exhibited a high conversion of FF (76%) with selectivity towards FA (100%) at 140 °C, 50 bar for 24 h. The MOF was reused four consecutive times with a loss in catalytic performance. The decrease in catalytic activity could be attributed to the formation of inactive Cu(0) as revealed by HR-TEM and XPS studies. The HR-TEM of spent Cu-MOF showed a uniform particle size diameter of 3.5 nm. This work is significant in providing new strategies for the design and fabrication of highly selective MOF catalysts for the FF upgrading. Wed, 01 Jan 2025 00:00:00 GMT https://cris.library.msu.ac.zw//handle/11408/6625 2025-01-01T00:00:00Z Moyo, Pamela S. Mehlana, Gift Matsinha Leah C. Makhubela Banothile C. E. https://cris.library.msu.ac.zw//handle/11408/6624 Title: Understanding metal–organic framework densification: solvent effects and the growth of Colloidal Primary Nanoparticles in Monolithic ZIF-8 Authors: Pathak, Ayush; Alghamdi, Lana A.; Fernández-Catalá, Javier; Tricarico, Michele; Cazorla-Amorós, Diego; Jin-Chong Tan; Ángel Berenguer-Murcia; Mehlana, Gift; Andrew E. H. Wheatley Abstract: To commercialize metal–organic frameworks (MOFs), it is vital they are made easier to handle. There have been many attempts to synthesize them as pellets, tablets, or granules, though they come with innate drawbacks. Only recently have these been overcome, through the advent of self-shaping densified or monolithic MOFs (monoMOFs), which require minimal post-synthetic modification and avoid poor structural integrity, intractability, and pore collapse or blockage. ZIF-8 (zeolitic imidazolate framework-8) has emerged as a prototypical monoMOF in pure and in situ doped forms. Now its formation in solvent mixtures is studied to better understand the early stages of monolith formation and improve the scope of monoliths for hosting solvent-sensitive guests. Solvent-, temperature- and coagulant-dependent control over reaction kinetics induces variations in morphology that are explained by relating the nucleation and growth rates of primary nanocrystallites to the stability of colloidal dispersions during reaction. This yields mesoporous monoZIF-8 with mean pore size 16 nm, SBET >1400 m2 g−1, bulk density 0.76 g cm−3, and resistance to permanent deformation exceeding previous reports. While the study highlights the powerful manipulation of monoMOF characteristics, a new understanding of the growth and stability of primary nanocrystallites has consequences for colloid synthesis generally. Wed, 01 Jan 2025 00:00:00 GMT https://cris.library.msu.ac.zw//handle/11408/6624 2025-01-01T00:00:00Z Pathak, Ayush Alghamdi, Lana A. Fernández-Catalá, Javier Tricarico, Michele Cazorla-Amorós, Diego Jin-Chong Tan Ángel Berenguer-Murcia Mehlana, Gift Andrew E. H. Wheatley https://cris.library.msu.ac.zw//handle/11408/6608 Title: Closing the loop in the Carbon Cycle: Enzymatic reactions housed in Metal-Organic Frameworks for CO2 conversion to Methanol Authors: Moyo Praise K.; Mehlana Gift; Tshuma Piwai; Chikukwa Evernice S.; Makhubela Banothile C. E. Abstract: The preparation of value-added chemicals from carbon dioxide (CO2) can act as a way of reducing the greenhouse gas from the atmosphere. Industrially significant C1 chemicals like methanol (CH3OH), formic acid (HCOOH), and formaldehyde (HCHO) can be formed from CO2. One sustainable way of achieving this is by connecting the reactions catalyzed by the enzymes formate dehydrogenase (FDH), formaldehyde dehydrogenase (FALDH), and alcohol dehydrogenase (ADH) into a single cascade reaction where CO2 is hydrogenated to CH3OH. For this to be adaptable for industrial use, the enzymes should be immobilized in materials that are extraordinarily protective of the enzymes, inexpensive, stable, and of ultra-large surface area. Metal–organic frameworks (MOFs) meet these criteria and are expected to usher in the much-awaited dispensation of industrial biocatalysis. Unfortunately, little is known about the molecular behaviour of MOF-immobilized FDH, FALDH, and ADH. It is also yet not known which MOFs are most promising for industrial enzyme-immobilization since the field of reticular chemistry is growing exponentially with millions of hypothetical and synthesized MOF structures reported at present. This review initially discusses the properties of the key enzymes required for CO2 hydrogenation to methanol including available cofactor regeneration strategies. Later, the characterization techniques of enzyme-MOF composites and the successes or lack thereof of enzyme-MOF-mediated CO2 conversion to CH3OH and intermediate products are discussed. We also discuss reported multi-enzyme-MOF systems for CO2 conversion cognizant of the fact that at present, these systems are the only chance of housing cascade-type biochemical reactions where strict substrate channelling and operational conditions are required. Finally, we delve into future perspectives. Wed, 01 Jan 2025 00:00:00 GMT https://cris.library.msu.ac.zw//handle/11408/6608 2025-01-01T00:00:00Z Moyo Praise K. Mehlana Gift Tshuma Piwai Chikukwa Evernice S. Makhubela Banothile C. E.