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The doctor blade coating method is used to prepare dye-sensitized solar cells (DSSCs) and dope the original titanium dioxide (TiO₂, P25) photoanode (PA) with single-layer graphene (G), graphene quantum dots (GQDs), and gold (Au) nanoparticles in this research. The results show that doping PAs with G, GQDS, and Au effectively increases the short-circuit current density ($J_{\mathrm{\text{sc}}})$, conversion efficiency ($\eta$), and decreases the internal structure impedance ($R_k$) of DSSCs. $J_{\mathrm{\text{sc}}}$ increases from 13.62 to 17.02, 15.22, 16.05 mA/cm², while $\eta$ (%) increases from 6.36 to 7.50, 7.08, 7.04% when doping G, GQDs, and Au, respectively. The analysis of Electrochemical Impedance Spectroscopy (EIS) reveals that the doping decreases $R_k$ from 11.28 to 8.36, 8.78, 8.54 $\mathrm{\Omega }$, respectively. Then, the titanium dioxide (TiO${}_2)$-doped G-GQDs, G-Au, and QDs-Au on DSSCs influence $J_{\mathrm{\text{sc}}}$ that increases to 5.45, 15.37, and 15.31 mA/cm², respectively. In this case, the values of $\eta$ are found to be 7.21%, 7.35%, and 7.00%, while those of $R_k$ are 8.44, 8.63, and 9.18 $\mathrm{\Omega }$. The values of $J_{\mathrm{\text{sc}}}$ and $\eta$ are highest but that of $R_k$ are lowest when doping with G, which proves that the photoanode of the DSSC effectively activates the photogenerated electrons in the film by doping single-layer graphene and TiO₂ captures its electrons through graphene. The decreasing electron–hole recombination rate allows the photogenerated electrons to be quickly transferred to the external circuit. As a result, the efficiency of DSSCs is improved.

Sn-doped TiO₂ nanomaterials were synthesized by sol–gel method. It was shown the phase compositions and phase transitions change with the introduction of different tin amounts (0.5–20mol.%). X-ray powder diffraction was used to study the effect of different tin amounts on the anatase–rutile phase transition. It was found that the introduction of ions increases the thermal stability of anatase modifications. The material’s photocatalytic activity was studied in reaction with a model pollutant (methylene blue) photodegradation under UV and visible light activation. The best photocatalytic properties were shown for material, which contains 5mol.% of Sn.

In this study, TiO₂/PAN-based fibers were prepared by electrospinning a composite solution containing both the desirable contents of TiO₂ and a 10 wt. % PAN polymer solution dissolved in N, N-dimethylformamide. The TiO₂ loaded electrospun PAN nanofibers were then carbonized at 1000 °C in N₂ atmosphere furnace after stabilization at 230 °C in air. Then CNF/TiO₂ nanofibers were oxidized at 450 °C in air. The morphology and structure of the TiO₂-embeded carbon nanofibers were investigated by SEM and Raman spectroscopy. Specific surface area was determined using BET equation from N₂ adsorption analysis. Photocatalytic tests were conducted in a UV illuminated set-up specialized for the filters using ethanol vapor. The results have shown that ethanol vapor was efficiently degraded on TiO₂/CNF composite nanofiber mat under UV illumination. The aim of this study was to further investigate the feasibility of TiO₂/ACF for practical indoor air purification.