Semiconductor doping can promote the photoelectrocatalytic application of semiconductor materials by constructing impurity energy levels and reducing the band gap. In this paper, we designed a preparation method for metal?doped semiconductor materials. The transition metal Co was combined with the anionic ligand of the metal?organic framework (MOF)MIL?125 through coordination. Then, the Co?doped TiO₂ was obtained through pyrolysis, and its performance in photocatalysis was studied. The results showed that the co?doped TiO₂ exhibits a high photocurrent density (9.87 μA/cm²), which is 3.8 times of the undoped TiO₂. Meanwhile, the degradation reaction rate constant also significantly increases from 0.041 min?1 before doping to 0.063 min?1 after doping. The incorporation of Co species not only extends the visible?light absorption edge of TiO₂ but also introduces well?defined impurity energy levels within its bandgap, thereby facilitating efficient separation and migration of photogenerated charge carriers while significantly suppressing electron?hole recombination.

Using sodium lignosulfonate and copper chloride dihydrate as raw materials, and activated carbon modified materials under different synthetic conditions were prepared by calcination under N₂ atmosphere by impregnation and activation. The structure and surface morphology of the prepared materials were studied by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other testing methods. Taking K₂Cr₂O₇ solution with mass concentration of 20 mg/L as the research object, the Cr(Ⅵ) content in the solution was detected by Diphenyl carbamide chromogenic method, and the adsorption capacity of the prepared activated carbon modified materials was calculated. According to the experimental results, when the proportion of copper is 20% and the calcination temperature is 700 ℃, the adsorption performance of the material is the best, and the adsorption capacity is 72.2 mg/g. The adsorption process conforms to the Langmuir monolayer adsorption and Pseudo-second-order kinetics.

In this work, the rutile mesocrystals TiO₂ were synthesized by hydrothermal method using layered titanate HTO (H_4x/3Ti_2-x/3□ _x/3O₄?nH₂O) as the precursor. By means of X?ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and other testing methods, the effect of reaction temperature on the synthesis of rutile?type mesoscopic TiO₂ crystal material by means of topological structure transformation was studied. The results reveal that rutile TiO₂ can be obtained under the condition of pH 0.5 of the reaction system, and with the gradual increase of the reaction temperature, the rutile?type mesoscopic TiO₂ crystal material is formed at 120 ℃. Taking Rhodamine B (RhB) as the pollutant model for degradation experiments, the photocatalytic activity of rutile mesocrystals TiO₂ is significantly higher than that of other samples. Experiments on dye?sensitized solar cells (DSSCs) show that the mesocrystals structure formed at 120 ℃ is conducive to the rapid migration of photogenerated carriers, thus obtaining high cell characteristics.

In this work, the HTO (H_4x/3Ti_2-x/3□ _x/3O₄·nH₂O) was used as the precursor raw material, and the nanoscale titanium oxide particles (ST01) were loaded on the surface of the HTO by water bath impregnation, and the TiO₂ homogeneous structure composite was topologically synthesized by calcination method. Using X?ray diffraction （XRD）, Raman spectroscopy (Raman) and other testing methods, the effect of calcination temperature on the phase transition process with titanium dioxide was studied in detail. The results indicate that the HTO can transfer to TiO₂（B）, anatase TiO₂ and rutile TiO₂ with increased temperatures, and the TiO₂ homophase composites are obtained with various structure and content of TiO₂. The degradation experiment was carried out with Rhodamine B （RhB） as the pollutant model. The photocatalytic activity of the sample at 600 ℃ is significantly higher than that of other samples, mainly because the separation efficiency of electrons and holes of the sample is the highest at this time, indicating that the structure and composition of homogeneous composite TiO₂ affect its photocatalytic activity. In addition, dye?sensitized solar cell （DSSCs） experiments show that the reason for the higher optoelectronic performance of the samples at 600 ℃ is that the two?dimensional sheet?like morphology facilitates the rapid migration of photogenerated carriers.