Photocatalytic Activity and Antibacterial Behavior of Fe3+-Doped TiO2/SnO2 Nanoparticles

Abstract

Problem statement: Since bacteria mainly causes damage on fresh vegetables and fruits during transportation to market, anti-bacterial TiO 2 photocatalyst was applied for their packaging films. However, it has been known that pure TiO 2 exhibits low photocatalytic property due to rapid recombination of photo-activated electrons and holes. Doping with metal or metal oxide shows the improvement of photocatalytic activity and disinfection effect. Approach: Fe 3+ was considered to dope into TiO 2 /3SnO 2 photocatalyst in order to enhance the photocatalytic property and bacterial inactivation efficiency. The Fe 3+ doped TiO 2 /3SnO 2 nanoparticles were prepared by sol-gel method and calcined at 400 °C for 2 h. The synthesized powders were characterized by XRD, BET and SEM. Photocatalytic activity and bacteria killing effect were determined by means of degradation of methylene blue solution and inactivation of E. coli bacteria, respectively. These tests were performed under UV and visible light irradiations. Results: Fe 3+ doping into TiO 2 /3SnO 2 has an effect on inhibition of anatase crystal growth, led to the enlargement of the composite specific surface area. Therefore, the photocatalytic activity of Fe 3+ doped TiO 2 /3SnO 2 composite in proper concentration was greater than those of pure TiO 2 and TiO 2 /3SnO 2 and 0.5 mol% Fe 3+ doping exhibited the highest photocatalytic activity and E.coli inactivation efficiency. The E. coli was completely killed within 90 min under UV irradiation or 99.7% inactivated under visible light exposure. Conclusion: Fe 3+ doped TiO 2 /3SnO 2 nanoparticles were successfully synthesized and identified as 100% anatase phase. The 0.5mol% Fe 3+ -doped TiO 2 /3SnO 2 which has particle size of 12.89 µm and specific surface area of 117.61 m 2 g −1 , exhibited the highest activity and disinfection efficiency. An attractive feature of Fe 3+ doped TiO 2 /3SnO 2 photocatalytic disinfection is its potential to be activated by visible light. Therefore, these composite TiO 2 nanoparticles can be utilized for fresh food packaging films.

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