Microflow synthesis and enhanced photocatalytic dye degradation performance of antibacterial Bi₂O₃ nanoparticles

Microreactors can play a crucial role in synthesis and rapid testing of various nanocatalyst to be used in addressing the issue of environmental contamination. We have reported the rapid fabrication of polydimethylsiloxane (PDMS) and poly(methyl methacrylate) (PMMA)-based microreactor for the flow synthesis and enhanced inline photocatalysis of bismuth oxide (Bi₂O₃) nanoparticles. A T-shaped microreactor with uniform circular cross-sectional channel having inner diameter of 450 μm was utilized for synthesizing Bi₂O₃ nanoparticles with narrow size distribution. Further, photocatalytic dye degradation efficiency for methyl orange (MO) was recorded by coating these Bi₂O₃ nanoparticles within the inner walls of PMMA-based serpentine microreactors under visible light. The enhanced dye degradation efficiency of as high as 96% within just 15 min of irradiation is reported. A comparative analysis has also been done for both conventional as well as the in-channel photocatalysis highlighting the advantages of microreactor based photocatalysis over the conventional method. Bi₂O₃ nanoparticles also showed excellent stability even after three cycles indicating reusability of coated microreactors in photocatalysis. The small concentration of as synthesized Bi₂O₃ nanoparticles also demonstrated high efficacy for the inhibition of Escherichia coli bacterial pathogens.