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Highlights: [•] Red-light-emitting La4Ti9O24:Eu3+ phosphor was obtained from sol–gel precursors. [•] Under 465nm excitation, the phosphor exhibits strong red emission at 613nm. [•] Doping with either Si4+ or Bi3+ enhances emission intensity of the phosphor. [•] The phosphor could be candidate for color mixing in white light-emitting diode. [ABSTRACT FROM AUTHOR]

Abstract: Flowerlike ZnO nanostructures composed of nanorods were synthesized by co-precipitation method using Zn(NO3)2·6H2O and (CH2)6N4 as reactants, polyethylene glycol 400 as surfactant. La2O3 was dispersed onto the obtained ZnO with a content of 0.5–2.0wt% to enhance the gas-sensing property. Gas-sensing results of the La2O3-doped ZnO to ethanol, acetone, ammonia and formaldehyde, respectively, reveal that response of La2O3-doped ZnO to a specified test gas is higher than that of no La2O3-doped. Response of 1.0wt% La2O3-doped ZnO to 200ppm acetone reaches 54.1 at the working temperature of 350°C, and the response time is only 8s, implying the potential for detection of low gas concentration. [Copyright &y& Elsevier]

To lessen the greenhouse effect, measures such as improving the recovery of crude oil and converting carbon dioxide (CO 2 ) into valuable chemicals are necessary to create a sustainable low-carbon future. To this end, the development of efficient new oil-displacing agents and CO 2 conversion has aroused great interest in both academia and industry. The Knoevenagel condensation and CO 2 cycloaddition are the key reactions to solve the above problems. Four Cu- or Zn-based molecular complexes built from different ligands possessing hydrophilic-hydrophobic layers and different dimensionalities were chosen as solid catalysts for this study. Structural analysis revealed the presence of hydrophilic-hydrophobic layers and open metal sites in the low-dimensional complexes. To obtain deep insight into the reaction mechanism, first-principles density functional theory (DFT) calculations were carried out. These calculations confirmed that in the Knoevenagel condensation reaction, the final formation of benzylidenemalononitrile is the rate-determining step (an energy barrier (Δ E ) value of 73.2 kJ mol -1 ). The zero-dimensional (0D) Cu molecular complex with unsaturated metal centers, hydrophilic and hydrophobic layers, exhibited higher catalytic activity (yield: 100%, temperature: room temperature, and time: 2 h) compared with one- and two-dimensional Cu complexes. In the presence of a 0D Zn complex co-catalyzed with Br - in the CO 2 cycloaddition reaction, the Δ E value reduces to 35.5 kJ mol -1 for the ring opening of styrene oxide (SO), which is significantly lower than Br - catalyzed (80.9 kJ mol -1 ) reactions. The roles of unsaturated metal centers, hydrophilic-hydrophobic layers and dimensionality in the Knoevenagel condensation and CO 2 cycloaddition were explained in the results of structure-activity relationships.