A new
facile method for synthesis of porous azo-linked polymers
(ALPs) is reported. The synthesis of ALPs was accomplished by homocoupling
of aniline-like building units in the presence of copper(I) bromide
and pyridine. The resulting ALPs exhibit high surface areas (SABET = 862–1235 m2 g–1),
high physiochemical stability, and considerable gas storage capacity
especially at high-pressure settings. Under low pressure conditions,
ALPs have remarkable CO2 uptake (up to 5.37 mmol g–1 at 273 K and 1 bar), as well as moderate CO2/N2 (29–43) and CO2/CH4 (6–8)
selectivity. Low pressure gas uptake experiments were used to calculate
the binding affinities of small gas molecules and revealed that ALPs
have high heats of adsorption for hydrogen (7.5–8 kJ mol–1), methane (18–21 kJ mol–1), and carbon dioxide (28–30 kJ mol–1).
Under high pressure conditions, the best performing polymer, ALP-1,
stores significant amounts of H2 (24 g L–1, 77 K/70 bar), CH4 (67 g L–1, 298 K/70
bar), and CO2 (304 g L–1, 298 K/40 bar).
In this article, we report the lowest-temperature CO oxidation catalyst supported on metal-organic frameworks (MOFs). We have developed a facile, general, and effective approach based on microwave irradiation for the incorporation of Pd nanoparticle catalyst within Ce-MOF. The resulting Pd/Ce-MOF material is a unique catalyst that is capable of CO oxidation at modest temperatures and also of efficient uptake of the product CO gas at low temperatures. The observed catalytic activity of this material toward CO oxidation is significantly higher than those of other reported metal nanoparticles supported on MOFs. The high activity of the Pd/Ce-MOF catalyst is due to the presence of Ce(III) and Ce(IV) ions within the metal-organic framework support. The Pd nanoparticles supported on the Ce-MOF store oxygen in the form of a thin palladium oxide layer at the particle-support interface, in addition to the oxygen stored on the Ce(III)/Ce(IV) centers. Oxygen from these reservoirs can be released during CO oxidation at 373 K. At lower temperatures (273 K), the Pd/Ce-MOF has a significant CO uptake of 3.5 mmol/g.
Heteroatom-doped porous carbons are generated through a one-step synthesis (including salt formation, carbonization and activation) using an organic monomer as the precursor.
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