Amine-Functionalized Titanate Nanosheet-Assembled Yolk@Shell Microspheres for Efficient Cocatalyst-Free Visible-Light Photocatalytic CO₂ Reduction

Exploiting advanced semiconductor photocatalyst with superior activity and selectivity for the conversion of CO₂ into solar fuels and valuable chemicals is of worldwide interest. In this report, hierarchical amine-functionalized titanate nanosheets based yolk@shell microspheres were synthesized via one-pot organic amine mediated anhydrous alcoholysis of titanium­(IV) butoxide. The selected organic amine, diethylenetriamine, played multiple roles. First, it was essential for the crystallographic, morphological and textural control of the synthesized titanate nanoarchitectures. Second, it was crucial for the in situ functionalization of titanate nanosheets by concurrent interlayer intercalation and surface grafting, which gave rise to the strong visible-light absorption ability and high CO₂ adsorption capacity. As a consequence of the synergetic tuning in multilevel microstructures, an integrated engineering of the multifunctional modules of the titanate-based photocatalysts was achieved for efficient CO₂ reduction toward solar fuels

Micellization and Adsorption of Heterogemini Surfactants Containing a Hydroxyl Headgroup in Aqueous Solution

The micellization of a homologous series of heterogemini surfactants, C_<i>m</i>OhpNC_<i>n</i> (<i>m</i>, <i>n</i> = 10, 8; 12, 8; 14, 8; 16, 8; and 10, 14), in aqueous solution and their adsorption at the air/water interface have been investigated by surface tension, conductivity, and fluorescence techniques. The surface tension curves of C₁₆OhpNC₈ and C₁₀OhpNC₁₄ showed two break points, corresponding to the critical concentration of the premicellar aggregation and the general micellization, respectively. The results of conductivity and fluorescence spectra using pyrene as probe confirmed the premicellization behavior in the two cases. This indicated that these surfactants have strong aggregation ability in the solution. The micelle formed nearby the <i>cmc</i> displayed only a small aggregation number but a large ionization degree. The <i>C</i>₂₀ that characters the efficiency in surface tension reduction was quite small in comparison with those of conventional surfactant and even smaller than those of symmetric gemini surfactants such as 12-s-12 homologous. The special molecular packing of C_<i>m</i>OhpNC_<i>n</i> in aqueous solution was closely related to the intermolecular hydrogen bonding and a weak electrostatic repulsion

Performance and Mechanism of Piezo-Catalytic Degradation of 4‑Chlorophenol: Finding of Effective Piezo-Dechlorination

Piezo-catalysis was first used to degrade a nondye pollutant, 4-chlorophenol (4-CP). In this process, hydrothermally synthesized tetragonal BaTiO₃ nano/micrometer-sized particles were used as the piezo-catalyst, and the ultrasonic irradiation with low frequency was selected as the vibration energy to cause the deformation of tetragonal BaTiO₃. It was found that the piezoelectric potential from the deformation could not only successfully degrade 4-chlorophenol but also effectively dechlorinate it at the same time, and five kinds of dechlorinated intermediates, hydroquinone, benzoquinone, phenol, cyclohexanone, and cyclohexanol, were determined. This is the first sample of piezo-dechlorination. Although various active species, including h⁺, e^–, •H, •OH, •O₂^–, ¹O₂, and H₂O₂, were generated in the piezoelectric process, it was confirmed by ESR, scavenger studies, and LC-MS that the degradation and dechlorination were mainly attributed to •OH radicals. These •OH radicals were chiefly derived from the electron reduction of O₂, partly from the hole oxidation of H₂O. These results indicated that the piezo-catalysis was an emerging and effective advanced oxidation technology for degradation and dechlorination of organic pollutants

Porous Fluorinated SnO₂ Hollow Nanospheres: Transformative Self-assembly and Photocatalytic Inactivation of Bacteria

Highly porous surface fluorinated SnO₂ hollow nanospheres (SnO₂(F) HNS) were produced in high yield by a hydrothermal treatment of stannous fluoride in the presence of hydrogen peroxide. Two important processes in terms of oriented self-assembly and in situ self-transformation were highlighted for the formation of as-prepared SnO₂(F) HNS, which were largely relying on the directing effects of selected specific chemical species in the present synthesis system. Significantly, these SnO₂(F) HNS showed considerable activity in photocatalytic inactivation of a surface negatively charged bacterium, Escherichia coli K-12, in aqueous saline solution. The dominant reactive species involved in the inactivation process were also identified