Boosting photocatalytic performances of lamellar BiVO4by constructing S-scheme heterojunctions with AgBr for efficient charge transfer.

Successful construction of heterojunction can improve the utilization efficiency of solar light by broadening the absorption range, facilitating charge-carrier separation, promoting carrier transportation and influencing surface-interface reaction. Herein, visible-light-driven AgBr was deposited on the surface of lamellar BiVO4which was prepared by a facile hydrothermal process to improve charge carrier separation, and subsequent photocatalytic effectiveness. The catalyst with an optimal AgBr/BiVO4ratio exhibited a superbly enhanced photocatalytic decolorization ability (about 6.85 times higher than that of pure BiVO4) and high stability after four cycles. The unique photocatalytic mechanism of S-scheme carrier migration was investigated on the bases of radical trapping tests and photo/electrochemical characterizations. Results showed that the enhanced migration strategy and intimately interfacial collaboration guaranteed the effective charge carriers separation/transfer, leading to magnificent photocatalytic performance as well as excellent stability.

Planar Mn4O cluster homochiral metal-organic framework for HPLC separation of pharmaceutically important (±)-ibuprofen racemate.

A planar tetracoordinated oxygen containing a homochiral metal-organic framework (MOF) has been synthesized and characterized that can be used as a new chiral stationary phase in high-performance liquid chromatography to efficiently separate racemates such as pharmaceutically important (±)-ibuprofen and (±)-1-phenyl-1,2-ethanediol.

A nitrate nonlinear optical crystal Pb16(OH)16(NO3)16 with a large second-harmonic generation response.

A noncentrosymmetric nitrate, Pb16(OH)16(NO3)16, has been obtained using a hydrothermal method. It is constructed of [Pb4(OH)4](4+) cubanes and nitrate form the overall three-dimensional structure via weak Pb-O bonds. Powder second-harmonic generation (SHG) using the Kurtz-Perry technique shows that Pb16(OH)16(NO3)16 is type I phase-matchable, and the measured SHG coefficient was 3.5 times that of KH2PO4. The direction and magnitude of the dipole moments in PbOn polyhedra and [NO3](-) triangles of Pb16(OH)16(NO3)16 have been quantified using the bond-valence approach, which shows that the large SHG response originates from the cooperation of PbOn polyhedra and [NO3](-) triangles. The band structure and density of states as well as electron density difference are calculated on the basis of density functional theory.

Tuning the Microstructures of ZnO To Enhance Photocatalytic NO Removal Performances.

Effective removal of kinetically inert dilute nitrogen oxide (NO, ppb) without NO2 emission is still a challenging topic in environmental pollution control. One effective approach to reducing the harm of NO is the construction of photocatalysts with diversified microstructures and atomic arrangements that could promote adsorption, activation, and complete removal of NO without yielding secondary pollution. Herein, microstructure regulations of ZnO photocatalysts were attempted by altering the reaction temperature and alkalinity in a unique ionic liquid-based solid-state synthesis and further investigated for the removal of dilute NO upon light irradiation. Microstructure observations indicated that as-tuned photocatalysts displayed unique nucleation, diverse morphologies (spherical nanoparticles, short and long nanorods), defect-related optical characteristics, and enhanced carrier separations. Such defect-related surface-interface aspects, especially Vo″-related defects of ZnO devoted them to the 4.16-fold enhanced NO removal and 2.76 magnitude order decreased NO2 yields, respectively. Improved NO removal and toxic product inhabitation in as-tuned ZnO was disclosed by mechanistic exploitations. It was revealed that regulated microstructures, defect-related charge carrier separation, and strengthened surface interactions were beneficial to active species production and molecular oxygen activation in ZnO, subsequently contributing to the improved NO removal and simultaneous avoidance of NO2 formation. This investigation shed light on the facile regulation of microstructures and the roles of surface chemistry in the oxidation of low concentration NO in the ppb level upon light illumination.

Electrochemical treatment of 2, 4-dichlorophenol using a nanostructured 3D-porous Ti/Sb-SnO2-Gr anode: Reaction kinetics, mechanism, and continuous operation.

2, 4-dichlorophenol (2, 4-DCP) is considered to be a highly toxic, mutagenic, and possibly carcinogenic pollutant. This study is focused on the electrochemical oxidation of 2, 4-DCP on nanostructured 3D-porous Ti/Sb-SnO2-Gr anodes, with the aim of presenting a comprehensive elucidation of mineralization process through the investigation of influential kinetics, the reactivity of hydroxyl radical's and analysis of intermediates. High efficiency was achieved at pH of 3 using Na2SO4 electrolytes at a current density of 30 mA cm-2. Under the optimized conditions, a maximum removal of 2, 4-DCP of up to 99.9% was reached, whereas a TOC removal of 81% was recorded with the lowest ECTOC (0.49 kW h g-1) within 40 min of electrolysis. To explore the stability of the 3D-Ti/Sb-SnO2-Gr electrodes, a continuous electrochemical operation was established, and the consistent mineralization results indicated the effectiveness of the 3D-Ti/Sb-SnO2-Gr system concerning its durability and practical utilization. EPR studies demonstrated the abundant generation of OH radicals on 3D-Ti/Sb-SnO2-Gr, resulting in fast recalcitrant pollutant incineration. From dechlorination and the reactivity of the OH radicals, several intermediates including six cyclic byproducts and three aliphatic carboxylic acids were detected, and two possible degradation pathways were proposed that justify the complete mineralization of 2, 4-DCP.

A perfectly aligned 63 helical tubular cuprous bromide single crystal for selective photo-catalysis, luminescence and sensing of nitro-explosives.

A perfectly aligned 63 helical tubular cuprous bromide single crystal has been synthesized and characterized, which can selectively decompose negatively charged dyes of Methyl Orange (MO) and Kermes Red (KR), and the photocatalytic efficiency is higher than that of nanosized (∼25 nm) TiO2 and ZnO. The direction and magnitude of the dipole moments as well as the band structure were calculated to reveal high photocatalytic efficiency. Moreover, luminescence studies indicate that the CuBr tube materials show very strong yellowish green emissions in the solid state and emulsion even at room temperature, and exhibit extremely high detection sensitivity towards nitro-explosives via fluorescence quenching. Detectable luminescence responses were observed at a very low concentration of 20 ppm with a high quenching efficiency of 94.90%. The results suggest that they may be promising multifunctional materials for photo-catalysis, luminescence and sensing of nitro-explosives.