The chemical industry contributes to 6% of global anthropogenic greenhouse gas (GHG) emissions. A handful of chemical processes (ammonia, nitric acid, methanol, olefins, aromatics, and chlor-alkali) ...account for 65% of those emissions. Decarbonization of the chemical industry will depend on addressing the intermittency of renewable electricity possibly via low-carbon hydrogen production using water electrolysis. A low-carbon power grid, which could happen in the next decade, would enable the chemical industry to reduce its GHG emissions by at least 35 percent. The remaining heat-based and direct emissions could be addressed by direct use of low-carbon electricity for heat or by generating hydrogen that can be used as a fuel and reducing agent coupled with CO
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capture and utilization efforts. Herein, we discuss how materials innovations could enable the transition to a lower carbon future when based on first-principles and economic realities.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We have examined the methane uptake properties of six of the most promising metal organic framework (MOF) materials: PCN-14, UTSA-20, HKUST-1, Ni-MOF-74 (Ni-CPO-27), NU-111, and NU-125. We discovered ...that HKUST-1, a material that is commercially available in gram scale, exhibits a room-temperature volumetric methane uptake that exceeds any value reported to date. The total uptake is about 230 cc(STP)/cc at 35 bar and 270 cc(STP)/cc at 65 bar, which meets the new volumetric target recently set by the Department of Energy (DOE) if the packing efficiency loss is ignored. We emphasize that MOFs with high surface areas and pore volumes perform better overall. NU-111, for example, reaches ∼75% of both the gravimetric and the volumetric targets. We find that values for gravimetric uptake, pore volume, and inverse density of the MOFs we studied scale essentially linearly with surface area. From this linear dependence, we estimate that a MOF with surface area 7500 m2/g and pore volume 3.2 cc/g could reach the current DOE gravimetric target of 0.5 g/g while simultaneously exhibiting around ∼200 cc/cc volumetric uptake. We note that while values for volumetric uptake are based on ideal single crystal densities, in reality the packing densities of MOFs are much lower. Finally, we show that compacting HKUST-1 into wafer shapes partially collapses the framework, decreasing both volumetric and gravimetric uptake significantly. Hence, one of the important challenges going forward is to find ways to pack MOFs efficiently without serious damage or to synthesize MOFs that can withstand substantial mechanical pressure.
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IJS, KILJ, NUK, PNG, UL, UM
Metal-organic frameworks--a class of porous hybrid materials built from metal ions and organic bridges--have recently shown great promise for a wide variety of applications. The large choice of ...building blocks means that the structures and pore characteristics of the metal-organic frameworks can be tuned relatively easily. However, despite much research, it remains challenging to prepare frameworks specifically tailored for particular applications. Here, we have used computational modelling to design and predictively characterize a metal-organic framework (NU-100) with a particularly high surface area. Subsequent experimental synthesis yielded a material, matching the calculated structure, with a high BET surface area (6,143 m(2) g(-1)). Furthermore, sorption measurements revealed that the material had high storage capacities for hydrogen (164 mg g(-1)) and carbon dioxide (2,315 mg g(-1))--gases of high importance in the contexts of clean energy and climate alteration, respectively--in excellent agreement with predictions from modelling.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Imine-linked microporous polymer organic frameworks (POFs) were synthesized via Schiff base condensation between 1,3,5-triformylbenzene and several readily available diamine monomers. Our facile, ...one-pot approach results in quantitative yields of POFs with the flexibility to incorporate several functional groups in their pores for tuning the interaction of their surface with different guest molecules. Synthesized POFs exhibit high specific surface areas (up to 1500 m2 g−1) as well as high isosteric heats of H2 adsorption (up to 8.2 kJ mol−1).
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It has long been established that the equilibrium properties of a water-oil-surfactant system governs the morphology of the emulsion formed-an inherently non-equilibrium system. In this work, we ...reinforce this concept and bring forward additional insights. Two types of 3-phase emulsions are examined, one obtained from suspension polymerization of silicone and acrylate in an aqueous phase and another obtained from mechanical dispersion of a silicone oil and a sunflower seed oil into an aqueous phase. We show that the specific emulsification process has an impact on the detailed structure of the final multiple droplets. In suspension polymerization, the complete miscibility of silicone with acrylate monomers prior to polymerization renders uniformity in the composition of the starting droplets; hence the final droplets after polymerization all have identical equilibrium tensions as well as relative volume ratios between the separated phases. Consequently, the final droplets have uniformly the same structure as predicted based on thermodynamics. On the other hand, the 3-phase emulsion formed from mechanical dispersion of two immiscible oils in water shows an overall morphology that is predicted by equilibrium tensions, however, a wide variation in the specific geometry is observed. This latter aspect reflects the randomness in drop break-up-and-recombination associated with the homogenization process, which results in variable volume ratio between the two immiscible oils among different droplets.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Complementary tetrahedral small molecule-DNA hybrid (SMDH) building blocks have been combined to form nucleic acid-based polymeric nanoparticles without the need for an underlying template or ...scaffold. The sizes of these particles can be tailored in a facile fashion by adjusting assembly conditions such as SMDH concentration, assembly time, and NaCl concentration. Notably, these novel particles can be stabilized and transformed into functionalized spherical nucleic acid (SNA) structures through the incorporation of capping DNA strands conjugated with functional groups. These results demonstrate a systematic, efficient strategy for the construction and surface functionalization of well-defined, size-tunable nucleic acid particles from readily accessible molecular building blocks. Furthermore, because these nucleic acid-based polymeric nanoparticles exhibited enhanced cellular internalization and resistance to DNase I compared to free synthetic nucleic acids, they should have a plethora of applications in diagnostics and therapeutics.
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A broad range of synthetically challenging-to-access small molecule–DNA hybrids can be readily synthesized in “one pot” and in high yields by coupling multi-azide cores to alkyne-modified DNAs on a ...solid support using click chemistry. The multi-functional products can be obtained in pure forms and on large scales (1 μmol) in a facile fashion. In addition, the distribution of the products can be controlled by changing the concentration of the azide core in solution and the strand-loading density on the solid-supports.
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To expand the utility of bis(terpyridine) metal connectivity, the selective symmetrical and unsymmetrical 4,4‘ ‘-functionalization (−CN, −Me, −CO2Me) of 4‘-(4-bromophenyl)-2,2‘:6‘,2‘ ‘-terpyridines ...was achieved using the Kröhnke synthesis. The final substituted 2,2‘:6‘,2‘ ‘-terpyridines along with their corresponding intermediates, 4a−c, were recrystallized and characterized by 1H NMR and 13C NMR as well as X-ray crystallography; COSY correlations were also conducted to permit definitive proton assignment.
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The reversible metal d-d orbital interaction and terpyridine interactions present new approaches to assemble structures that can be used as molecular switches. Their synthesis, physical properties, ...and supramolecular constructs are explored.
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Aqueous dispersions of graphene oxide are inherently unstable in the presence of electrolytes, which screen the electrostatic surface charge on these nanosheets and induce irreversible aggregation. ...Two complementary strategies, utilizing either electrostatic or steric stabilization, have been developed to enhance the stability of graphene oxide in electrolyte solutions, allowing it to stay dispersed in cell culture media and serum. The electrostatic stabilization approach entails further oxidation of graphene oxide to low C/O ratio (∼1.1) and increases ionic tolerance of these nanosheets. The steric stabilization technique employs an amphiphilic block copolymer that serves as a noncovalently bound surfactant to minimize the aggregate-inducing nanosheet–nanosheet interactions. Both strategies can stabilize graphene oxide nanosheets with large dimensions (>300 nm) in biological media, allowing for an enhancement of >250% in the bioconjugation efficiency of streptavidin in comparison to untreated nanosheets. Notably, both strategies allow the stabilized nanosheets to be readily taken up by cells, demonstrating their excellent performance as potential drug-delivery vehicles.
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