[en] In the present paper, a diamine ligand possessing an electron-pulling group 2-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole (denoted as PPYO) and its corresponding Re(I) complex Re(CO)₃(PPYO)Br were synthesized and carefully characterized. The geometric structure of Re(CO)₃(PPYO)Br was analyzed by its single crystal XRD. Theoretical calculation on the crystal suggested that the first few electronic excitations owned a mixed character of metal-to-ligand-charge-transfer (MLCT) and ligand-to-ligand-charge-transfer (LLCT). By doping Re(CO)₃(PPYO)Br into a polymer host of poly(vinylpyrrolidone) with electrospinning technique, composite fibers were yielded. The photophysical feature comparison between bulk samples and composite fibers was performed, which suggested that both face-to-face π–π attraction in crystal and the immobilization in PVP matrix could repress the MLCT excited state geometric relaxation, leading to improved emissive parameters including emission blue shift, longer excited state lifetime and better photostability. -- Highlights: • A Re(I) complex owing oxadiazole group was synthesized and fully characterized. • Its geometric structure and electronic transitions were investigated. • Composite fibers were constructed by doping it into a polymer host. • The photophysical features of bulk sample and composite fibers were compared. • Improved performance was observed by restraining geometric relaxation

[en] Bi₂S₃/BiOBr nanocomposites with various weight percents of Bi₂S₃ were successfully prepared by a facile hydrothermal process at 433 K, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, energy dispersive X-ray spectroscopy (EDS), UV–vis diffuse reflection spectra (UV–vis DRS) and nitrogen physisorption studies. The UV and visible photocatalytic activities of the as-prepared Bi₂S₃/BiOBr samples were evaluated by the photo-degradation of methyl orange (MO) in an aqueous solution. The results showed that the photocatalytic activity of the Bi₂S₃/BiOBr samples was greatly enhanced, compared with that over pure Bi₂S₃ and BiOBr. The enhanced photocatalytic activities could be mainly attributed to the effective transfer of the photogenerated electrons and holes at the heterojunction interface of Bi₂S₃ and BiOBr, which reduced the recombination of electron–hole pairs, and the mechanism of photocatalytic activity enhancement was discussed.

[en] The crystal density and Mohs hardness of zinc cadmium thiocyanate (ZCTC), ZnCd(SCN)₄ have been measured at room temperature. The specific heat of the crystal is 699.5 J mol^-1 K^-1 at 300 K. The thermal expansion coefficient (TEC) along the a and c axes, respectively, is interpreted on the basis of crystal structure. The thermal decomposition process is characterized by thermogravimetry analysis and differential scanning calorimetry (TGA/DSC). The intermediates and final products of the thermal decomposition were identified by X-ray powder diffraction at room temperature. The high-temperature effect in air on the optical transmission of the crystal was also studied

[en] Hydrogen from coal-based syngas is usually purified by deep desulfurization and decarbonization scrubbing technologies. Such electricity consuming processes cost a large number of heat exchangers and compressors. In this study, a two-stage demonstration unit had been constructed and demonstrated to purify hydrogen (including useful nitrogen for ammonia synthesis) from on-site sideline shift gas mixture at Yangmei Fengxi ammonia plant. For the first stage, an 8-column hydrogen purification process by novel elevated temperature pressure swing adsorption (ET-PSA, operated at 180 to 220 °C) was developed and demonstrated to capture H₂S and CO₂ simultaneously by hydrophobic activated carbon (AC) to reduce the impurities compared to that of room temperature PSA. Working condition at elevated temperature was proved to be appropriate and stable for reversible H₂S removal by AC. The second stage was a temperature swing adsorption for deep purification of CO to 0.2 ppm by commercial CuCl monolayer dispersed zeolites (PU-1 synthesized by Beijing Peking University Pioneer Technology Co., Ltd.). In order to examine the standard of trace impurities such CO and H₂S in product H₂, the purified H₂ was offered to a 3 kW proton exchange membrane fuel cell (PEMFC) stack to prove that all carbon and sulfur impurities met the demand not only for ammonia synthesis, but for PEMFC as well. Besides, two novel PSA steps: high pressure steam rinse and low pressure nitrogen purge were adopted to improve H₂ recovery to above 93%. To demonstrate its stability, over 2500 h of operation had been carried out on the small-scale demonstration rigs by far.