Synthesis and Photodegradation of Bi2O3 and Pb-Bi2O3 Nanoparticles and Their Kinetic Study

The green synthesis method synthesized the bismuth oxide and lead-doped bismuth oxide nanoparticles using Ferula Asafoetida leaves extract. The lead-doped bismuth oxide showed greater degradation efficiency than undoped bismuth oxide. This greater efficiency was due to decreases in the band gap energy between the valence band and the conduction band of the metal oxide and reduced the chances of electron-hole pair recombination with the metal oxide catalyst. The synthesized nanoparticles were characterized by TGA, SEM, FT-IR, EDX, XRD, and UV- visible Spectrometer. XRD diffraction of Bi2O3 nanoparticles reflected a strong and sharp peak at 32.8˚ shows that Bi2O3 nanoparticles are in crystalline phase. The crystallite size of Bi2O3 nanoparticles is 13.433 nm, and Pb-doped Bi2O3 is 9.6 nm, calculated from the Debye-Scherrer equation. The synthesized Bi2O3 nanoparticles are round in shape with average size of ~ 90-100 nm While Pb doped Bi2O3 is ~ 75 f- 100 nm. The EDX spectra showed no additional peak for any impurities. The degradation rate of Malachite Green dye (MG) increased with the increase in contact time and temperature, while it decreased with increasing dye initial concentration and pH. Initially, the degradation efficiency of the bismuth oxide catalyst is increased with increasing catalyst amount, but after a certain amount of catalyst, it started decreasing as the catalyst amount was further increased. The irradiation time on photodegradation is deliberate, keeping other parameters steady at catalyst quantity 0.01 g at specific reaction conditions. Moreover, the dye showed an increase in degradation at 50 oC. The utmost degradation of 92% was observed for lead-doped bismuth oxide (Bi2O3) and 76% for undoped bismuth oxide (Bi2O3).