In situ regulation of oxygen vacancies of porous TiO ₂ at atomic scale with promoting photocatalytic efficiency.

N-substituted metal-coordinated cross-linking polybenzimidazole pyridine sulfone, as novel class of high-performance functional polymers, has been obtained by the coordination of N-substituted polybenzimidazole pyridine sulfone (Py-N-PBIS) ligand with varying content of metallic ion (Co²⁺, Ni²⁺, Zn²⁺). The structures of the polymers are characterized by means of fourier transform infrared spectroscopy (FT-IR) and ¹H nuclear magnetic resonance (¹H NMR) spectroscopy, the results show good agreement with the proposed structures. Thermogravimetric analysis measurements exhibit that the metal coordination polymers possess good thermal stability with high thermal decomposition temperature (thermally stable up to 405–510°C). More importantly, the thermal decomposition temperature of Py-N-PBIS-(Co²⁺, Ni²⁺, Zn²⁺) can be nondestructively detected by taking advantage of the fluorescence quenching effect of metal coordination to 2,6-Bis(2-benzimidazolyl)pyridine structure.

The simple yet efficient and versatile fabrication of colloidal crystals was investigated based on the solidification-induced colloidal crystallization process with particle/water suspension as precursor. The resulting colloidal crystals were constituted by crystal grains with sizes ranging from several tens of micrometers to a few millimeters. Each of the grains had a close-hexagonal array of colloids, which endowed the bulk colloidal crystal powders with some specific optical properties. The freezing of water was shown as the major driving force to form colloidal crystal grains, which supersaturated the solution with nanoparticles and thus induced the formation and growth of colloidal crystal seeds. This process is intrinsically different from those conventional methods based on shearing force, surface tension, columbic interaction or magnetic interaction, revealing a new strategy to fabricate colloidal crystals in a convenient and efficient way.