Influences of chemical composition, microstructure and bandgap energy on photocatalytic and antimicrobial activities of ZnO and Ag-doped ZnO by solution combustion technique

O Jongprateep, K Meesombad, R Techapiesancharoenkij, K Surawathanawises, P Siwayaprahm, P Watthanarat

Abstract


Antibacterial agents, self-cleaning materials, H2 generators and air purifiers are among common applications of photocatalysts. ZnO is a low cost material with prominent photocatalytic performance. It is generally accepted that enhancement of photocatalytic activities of powders can be achieved through doping, particle refinement, as well as tailoring of bandgap energy. It has been reported that proper doping of zinc oxide by silver lead to reduction of bandgap energy, promoting electron and hole generation, which results in enhanced photocatalytic performance. The present study aims at synthesizing ZnO and ZnO doped with 2.5, 5, and 10 mol% Ag by solution combustion technique. Influences of chemical composition, microstructure, and bandgap energy on photocatalytic activities were also examined. Compositional analysis revealed an increasing trend of Ag phase formation with greater doping content. Microstructural examination indicated that all powders contained fine particles, which agglomerated into non-uniformed clusters with average sizes ranging from 99 to 255 nm. Values of optical bandgap ranging from 3.40 to 3.22 eV were observed. The greatest and the least amount of photocatalytic degradation of methylene blue, examined at wavelength closed to 290 nm in 90 min, were found in ZnO with 2.5 mol% Ag and ZnO with 5 mol% Ag, respectively. The antibacterial activity of the powders revealed the same trend as that of the photocatalytic degradation. The antibacterial activity of the powders revealed the same trend as that of the photocatalytic degradation, with the maximum Staphylococcus aureus reduction of 93.88% in ZnO powder with 2.5 mol% Ag.

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Printed ISSN: 0857-6149

Online ISSN: 2630-0508