Enlarging the range of viable nanoporous carbon precursors, namely by the acid treatment of low density biomass residues, can overcome issues related with the availability and quality of raw materials that have potential impact on cost and quality grade of the final product. Experiments Nanoporous carbons were prepared following a two-step process: H 2 SO 4 digestion/polycondensation of biomass waste (Agave sisalana, sisal) to obtain acidchars that were further activated with KOH or K 2 CO 3. Selected synthesized nanoporous carbons were tested for the removal of pharmaceutical compounds-ibuprofen and iopamidol-in aqueous solutions. Findings The structure and density of the acid-chars are highly dependent on the concentration of H 2 SO 4 used in the digestion and polycondensation steps. An adequate choice of the acid-char synthesis conditions, activating agent and contact method allowed to feature nanoporous carbons with specific surface areas ranging from 600 to 2300 m 2 g-1 and apparent densities reaching 600 kg m-3. The adsorption capacity of a sample obtained by KOH-activation for the removal of micropollutants from water was twice higher than the value attained by golden activated carbon (Cabot-Norit) commercialized for this specific purpose.

Layered cobalt oxide perovskites are important mixed ionic and electronic conductors. Here, we investigate LaBaCo 2 O 6−δ using in situ neutron powder diffraction. This composition is unique because it can be prepared in cubic, layered, and vacancy-ordered forms. Thermogravimetric analysis and diffraction reveal that layered and disordered samples have near-identical oxygen cycling capacities. Migration barriers for oxide ion conduction calculated using the bond valence site energy approach vary from E b ∼ 2.8 eV for the cubic perovskite to E b ∼ 1.5 eV for 2D transport in the layered system. Vacancy-ordered superstructures were observed at low temperatures, 350–400 °C for δ = 0.25 and δ = 0.5. The vacancy ordering at δ = 0.5 is different from the widely reported structure and involves oxygen sites in both CoO 2 and LaO planes. Vacancy ordering leads to the emergence of additional migration pathways with low-energy barriers, for example, 1D channels with E b = 0.5 eV and 3D channels with E b = 2.2 eV. The emergence of these channels is caused by the strong orthorhombic distortion of the crystal structure. These results demonstrate that there is potential scope to manipulate ionic transport in vacancy-ordered LnBaCo 2 O 6−δ perovskites with reduced symmetry.

The metal–organic framework CAU-10-NO2 [Al­(OH)­BDC-NO2] (CAU stands for Christian-Albrechts-University; H2BDC-NO2 is 5-nitroisophthalic acid) was observed to exhibit unexpected photochemical reactivity. Upon irradiation of the MOF with UV light with a wavelength of 365 nm (or with sunlight), guest molecules inside the pore system of the MOF can be oxidized and stable radicals are formed from the organic linker molecules. The reactivity toward different alcohols was studied by UV/vis spectroscopy and EPR spectroscopy. The amount of generated radicals depends on the size of the solvent molecules; however, as an exception, methanol shows a much lower reactivity than ethanol. DFT calculations were carried out to gain insights into these photochemical reactions. The results indicate that the nitro group is reduced to form a nitroso moiety. This was confirmed by means of NMR spectroscopy. The exact nature of the radical could not be revealed, but the results indicate that it could be a further reduced anionic nitroso radical. Methanol and ethanol can be distinguished using this photochemical reaction simply by the coloring of the irradiated MOF. Such a property is characteristic for a sensor; therefore, a synthesis procedure was developed to implement the MOF into a device by which the compound was directly grown onto gold substrates.

Scattering affects excitation power density, penetration depth and upconversion emission self-absorption, resulting in particle size –dependent modifications of the external photoluminescence quantum yield (ePLQY) and net emission. Micron-size NaYF4:Yb3+, Er3+ encapsulated phosphors (∼4.2 µm) showed ePLQY enhancements of >402%, with particle-media refractive index disparity (Δn): 0.4969, and net emission increases of >70%. In sub-micron phosphor encapsulants (∼406 nm), self-absorption limited ePLQY and emission as particle concentration increases, while appearing negligible in nanoparticle dispersions (∼31.8 nm). These dependencies are important for standardising PLQY measurements and optimising UC devices, since the encapsulant can drastically enhance UC emission.

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