This paper investigates the use of A. vera extract as a natural capping agent for TiO₂ nanoparticles as well as a reducing agent for TiO₂ nanoparticles. XRD, ultraviolet diffuse reflectance (UV-DRS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDXA) were used to characterize the material. In their X-ray diffraction patterns, the titanium dioxide nanoparticles were found to have a high degree of crystallinity, indicating that they were synthesized. Infrared (FT-IR) spectra were used to determine the chemical composition of the plant extract. The DRS spectra in the UV-visible range reveal a high absorption peak at 356 nm, which indicates the existence of TiO₂ nanoparticles in the sample. Shape of nanoparticles was revealed by SEM and TEM morphological investigations, which revealed their irregular and somewhat spherical nature. Only titanium and oxygen compounds were found in the EDX spectrum, indicating that they were present. This demonstrates that the NPs that were produced are devoid of contaminants. Using the produced nanoparticles as catalyst, we presented a photocatalytic degradation method for the dye methylene blue in this paper. The findings showed that 94 percent of the damage occurred within 120 minutes of being exposed to UV radiation.

People are using biodiesel in compression ignition engines because it is more environmentally friendly and can be used as a good alternative to diesel. There is a new technology called nanoparticles that can change the way a fuel works. Because waste cooking has a lot of oil in it, it can make biodiesel. To make biodiesel, transesterification was used to turn nonedible oil from waste cooking oil into biodiesel that could be used. Nanoparticles made of titanium oxide were studied by using scanning electron microscopy, transmission electron microscopy, as well as energy dispersive X‐ray analysis, among other things. TiO2 nanoparticles are spread out in different amounts in the biodiesel blend. The dosage levels range from 25, 50, 75, and 100 ppm. Tests on how titanium nanoparticles in a waste cooking oil biodiesel blend affect a diesel engine’s performance and how it emits were conducted in this study too. At a steady speed, the engine was used when there was a lot of work to do. Tests show that the WCOME 20 TiO2 100 ppm blend worked well. With the increase in the concentration of nanoparticles, there is an increase in brake thermal efficiency and at the same time, there is a decrease in BSFC. It is also less harmful to the environment than other blends, except for NOx, which does no’t change.