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PKU-5 (Al 4 B 6 O 15 ) is potentially a solid acid catalyst, and it possesses an interesting open-framework composed of [AlO 6 ] and [B 2 O 5 ] groups. PKU-5 shows a high thermal stability, while no physical and chemical properties were investigated thus far, because of the difficulty in its synthesis. Cr-stabilized PKU-5 with the formula (Al 1− x Cr x ) 4 B 6 O 15 (0.08 ≤ x ≤ 0.14) can be easily prepared by annealing Cr-doped PKU-1 precursors. XRD and TEM experiments demonstrate Cr 3+ has been successively incorporated into the framework of PKU-5. NH 3 -TPD measurements indicate that the partial substitution of Al 3+ by Cr 3+ leads to a small change of acid sites in total amounts and distributions. Cr-PKU-5 shows a good catalytic activity for methanol dehydration from 300 to 450 °C. Other operation conditions, such as the Cr 3+ content, space velocity of methanol were also discussed in detail to evaluate its catalytic performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] MNb2O6 was prepared by a mild two-step hydrothermal method. [•] Their flower-like nanostructure morphology was studied by SEM and TEM. [•] High BET surface areas for MnNb2O6 (∼50m2/g) and ZnNb2O6 (∼100m2/g). [•] Band gap energies were estimated by UV–vis diffuse reflectance spectra. [•] Photocatalytic activities were evaluated under UV-light irradiation. [ABSTRACT FROM AUTHOR]

Abstract: CdB10O14(OH)4·H2O has been synthesized under boric acid flux condition and characterized by single-crystal X-ray diffraction, infrared spectra, and UV–vis reflectance spectroscopy. It crystallizes in the monoclinic space group P21/n with a =7.7277(8), b =18.95(2), c =9.8616(10)Å, β=91.454(1)°, V =1443.7(3)Å. The structure consists of [B10O16(OH)4] layers of 9-membered borate rings enclosing Cd2+ cations. Adjacent borate layers are interconnected via hydrogen bonding to form a 3D network. It possesses an unprecedented decaborate fundamental building block B10O20. The structure details are discussed together with Sr[B6O9(OH)2]·3H2O, Pb[B8O11(OH)4], Pr[B8O11(OH)5], and Nd[B9O13(OH)4]·H2O, which have correlated FBBs. The band structure calculations show its direct energy band gap of ∼4.68eV, in consistent with the estimated value (4.77eV) from UV–vis. In addition, dielectric constants and refractive indexes are also calculated. [Copyright &y& Elsevier]