Yb³⁺ and Er³⁺ co-doped Y₂Ce₂O₇ nanoparticles sintered at different temperatures were prepared by homogeneous co-precipitation method. The products were characterized by X-ray powder diffraction (XRD), energy-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The results indicated that the particle sizes and morphologies of the samples were heavily influenced by the sintering temperature. As temperature increased, the particle sizes became gradually larger and more agglomerate. The emissions including green and red upconversion emissions were investigated under 980 nm excitation. The emission intensities of the samples also depended on the sintering temperature. Two photon processes were mainly responsible for green and red upconversion emissions.

In this study, silver nanowires (AgNW$_s$) were prepared by the polyol method using silver nitrate (AgNO$_3$) asthe silver source and polyvinylpyrrolidone (PVP) as the structure-directing agent under different reaction conditions. Inorder to obtain AgNW$_s$ with good uniformity and electrical conductivity, the orthogonal experiment method was adopted to design an experimental scheme. The scanning electron microscope, energy-dispersive X-ray spectrometer, X-ray diffraction, UV-2550 UV–Visible spectrophotometer, transmission electron microscope, Fourier transform infrared and Raman spectra were combined to characterize synthesized AgNW$_s$. It can be concluded from experimental data that when the reaction temperature is 150$^{\circ}$C, the ratio of AgNO$_3$ to PVP is 1:3, the drop rate of PVP is 65 ml h$^{–1}$, with the existence of ferric chloride (FeCl3), and the AgNW$_s$ exhibit optimal morphology with the diameter ranging from 60 to 200 nm. The results in this study will provide experimental guide for controllable formation of AgNW$_s$.

The preparation of titanium dioxide fibres with high specific surface area as a catalyst carrier is of great significance for the subsequent development of TiO$_2$ fibres in the field of electrocatalysis. In this article, the electrospinning technology combined with sol–gel method was adopted to manufacture mesoporous TiO$_2$ fibres using tetrabutyl titanate as the titanium source, polyethylene pyriolanone as the polymer template and ethanol as the solvent. By means of cold field-emission scanning electron microscopy, transmission electron microscopy, desktop electron microscope (TM3030), energy dispersive X-ray spectroscopy, thermal analyzer, X-ray diffraction, X-ray photoelectron spectroscopy, porometer 3G specific surface area and pore size analyzer, the morphology characterization of TiO$_2$ fibre under different conditions was analysed and the optimal preparation parameters of mesoporous TiO$_2$ fibres was proposed.