Cu-Al spinel oxide, which contains a small portion of the CuO phase, has been successfully used in methanol steam reforming (MSR) without prereduction. The omission of prereduction not only avoids the copper sintering prior to the catalytic reaction, but also slows down the copper-sintering rate in MSR. During this process, the CuO phase can initiate MSR at a lower temperature, and CuAl2O4 releases active copper gradually. The catalyst CA2.5-900, calcined at 900 °C with n(Al)/n(Cu) = 2.5, has a higher CuAl2O4 content, higher BET surface area, and smaller CuAl2O4 crystal size. Its activity first increases and then decreases during MSR. Furthermore, both fresh and regenerated CA2.5-900 showed better catalytic performance than the commercial Cu-Zn-Al catalyst.

Zirconium-based metal−organic frameworks (Zr-MOFs) have attracted tremendous attention as promising candidates for removing toxic chemicals under ambient conditions in virtue of their remarkable thermal, mechanical, and chemical stability. Here, we demonstrate for the f irst time the enhanced performance of nanoporous dicarboxylic acid-functionalized MOF-808 analogues toward NO 2 removal under both dry and moist conditions. Based on a pK a -directed solvent-assisted ligand exchange (SALE) strategy, a series of dicarboxylic acid ligands, including isophthalic acid, 5-hydroxyisophthalic acid, 5-aminoisophthalic acid, 5-nitroisophthalic acid, and pyridine-3,5-dicarboxylic acid, were precisely incorporated into the MOF-808 framework via substitution of formate ligands. The assembled MOF-808 derivatives demonstrated good crystallinity, well-defined morphology, high porosities, and tunable dicarboxylic acid contents, with the maximum molar ratios of dicarboxylic acid ligands to 1,3,5-benzenetricarboxylic acids in frameworks larger than 1:1. The microbreakthrough tests showed that the 5-aminoisophthalic acid-modified MOF-808 (808-NH 2 IPA) exhibited a significant enhancement in NO 2 capacities and the most remarkable reduction in the release of toxic NO byproduct as compared to pristine MOF-808. Detailed removal mechanisms for NO 2 were developed on the basis of multiple ex-situ characterization techniques and in-situ infrared Fourier transform spectroscopy. The effects of humidity on the mechanisms were also discussed. The reactions between the amino groups and NO x , yielding nitramines, nitrosamines, and arenediazonium salts, were proposed to play a major role for the outstanding performance of 808-NH 2 IPA for dry NO 2 removal. The acid−base reaction between HNO 3 and the amino groups preponderated in the moist NO 2 removal process, with the anilinium nitrate species turning into the principal product.

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(1 − x)BiVO4–xYVO4 (x ≤ 0.65) ceramics were prepared using the solid state reaction method. Bi–O oscillations were proved to dominate the microwave dielectric polarizations.