A novel yellow emitting long-persistent phosphor Ca₂BO₃Cl:Eu²⁺,Dy³⁺ is developed. The incorporation of Dy³⁺ ions, which act as trap centers, largely extends the thermoluminescence characteristics and evidently enhances the persistent luminescence behavior of the phosphor. Both fluorescence and phosphorescence spectra of Ca₂BO₃Cl:Eu²⁺,Dy³⁺ reveal only one asymmetric broad emission band located at 580 nm, ascribed to the 5d–4f transitions of Eu²⁺ ions in two different sites. With the optimum doping concentration and sufficient excitation with UV light, the afterglow of samples can persist over 48 h above the recognizable intensity level (≥0.32 mcd m⁻²), a phenomenon that is infrequent and excellent. Furthermore, Ca₂BO₃Cl possesses an indirect bandgap of about 5.1 eV. Detailed processes and possible mechanism are studied and discussed.

A series of composites of nanocrystalline TiO₂ with exposed {001} facets and high quality graphene sheets (GS) were synthesized via a one-step hydrothermal reaction in an ethanol–water solvent. The obtained {001} facets-exposed TiO₂/GS photocatalysts were characterized by Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible (UV-vis) diffuse reflectance spectroscopy (DRS) and Electrical Impedance Spectroscopy (EIS). They showed a better photocatalyst properties than P25 and other normal TiO₂/GS composites, which could be explained on the basis of the formation of chemical Ti–O–C bond and the formation of nano-sized Schottky interfaces at the contacts between TiO₂ and GS. The influence of the exposed {001} facets on the photocatalytic activity was investigated. The result showed that positively charged dye molecules are preferentially adsorbed onto the TiO₂/GS composites due to the photogenerated charge gathered on GS. Overall, this work could provide new insights into the fabrication of TiO₂–carbon composites as high performance photocatalysts and facilitate their application in addressing environmental protection issues.

Graphene sheets were obtained through solvothermal reduction of colloidal dispersion of graphene oxide in benzyl alcohol. The graphene/rod-shaped TiO₂ nanocomposite was synthesized by this novel and facile solvothermal method. During the solvothermal reaction, both the reduction of graphene oxide and the growth of rod-shaped TiO₂ nanocrystals as well as its deposition on graphene occur simultaneously. The photocatalytic activity of graphene/rod-shaped TiO₂ and graphene/spherical TiO₂ nanocomposites was compared. In the photocatalytic degradation of methyl orange (MO), the graphene/rod-shaped TiO₂ nanocomposite with the optimized graphene content of 0.48 wt% shows good stability and exhibits a significant enhancement of photocatalytic activity compared to the bare commercial TiO₂ (P25) and graphene/spherical TiO₂ nanocomposite with the same graphene content. Photocurrent experiments were performed, which demonstrate that the photocurrent of the graphene/rod-shaped TiO₂ nanocomposite electrode is about 1.2 times as high as that of the graphene/spherical TiO₂ nanocomposite electrode. The photocatalytic mechanism of graphene/rod-shaped TiO₂ nanocomposite was also discussed on the basis of the experimental results. This work is anticipated to open a possibility in the integration of graphene and TiO₂ with various morphologies for obtaining high-performance photocatalysts in addressing environmental protection issues.

Anatase/rutile mixed titania nanotubes (TiO₂ NTs) precipitated with gold nanoparticles (Au NPs), i.e. Au/TiO₂, have been synthesized and investigated on visible photocatalysis properties. A deposition–precipitation (DP) method was adopted to reduce the gold precursor to Au NPs within the preformed TiO₂ NTs by the emulsion electrospinning technique. The optimal visible photocatalytic activity was found in the sample Au₃(DP₃₅₀)/TiO₂ with a loading of 3 wt% Au NPs and calcining at 350 °C. Through transmission electron microscopy, Au NPs of 4.16 nm diameter were observed at the interface between the anatase and rutile phases in the optimal Au₃(DP₃₅₀)/TiO₂ sample, and these joint active sites at the interface were beneficial for charge separation. The obtained optimal photocatalytic efficiency of Au₃(DP₃₅₀)/TiO₂ was ascribed to the synergistic effect of the enhanced visible absorption and the anatase/rutile mixed-phase composition, and the possible mechanism for this was discussed in detail.

We reported the synthesis of a novel red long-afterglow material Sr₂SnO₄:Sm³⁺. Comparing with the air-sintered sample, a significant enhancement in both the fluorescence and phosphorescence for the vacuum-sintered sample was observed. This improvement could be attributed to the increase of oxygen vacancies which act as the sensitizer and the electron traps for the effective energy transfer from Sr₂SnO₄ host to Sm³⁺. The defects act as traps were investigated with thermoluminescence. For the presence of deep stable traps able to immobilize the energy permanently at room temperature, the Sr₂SnO₄:Sm³⁺ could be considered as a potential storage phosphor as well.

The brand new LLP material Ca ₆ BaP ₄ O ₁₇ :Eu ²⁺ ,Ho ³⁺ exhibits about 0.13 cd m ⁻² initial LLP intensity and a 47 h afterglow.