A study of Nb-doped ZnO ceramic and its enhanced solar photocatalysis, photoluminescence and antimicrobial properties

The present study aimed to produce pure and Nb-doped ZnO particles and analyze the effects of different amounts of Nb on the ZnO lattice, obtaining a material that can exhibit good performance in different optical and antimicrobial applications. Pure ZnO and Nb-doped (1, 2, 4 and 8 mol%) particles were prepared using a microwave-assisted hydrothermal method for 20 min at 130°C and heat treated at 500°C for 2 h. The structural results showed that doping created defects that reduced their growth, and the morphological results verified a reduction in particle size and a preferential rod-shaped arrangement of nanoparticles for the Z4N and Z8N (4 and 8 mol% Nb) samples. The band gap values showed low variation (from 3.23 to 3.28 eV), but doping was sufficient to generate defects that influenced the photocatalytic and photoluminescence (PL) properties. For PL emission, Z8N moved toward a green color and showed the highest PL intensity, which may have caused a lower photocatalytic efficiency. The photocatalytic properties of the materials under solar radiation were tested against methylene blue (MB) and crystal violet (CV) separately and mixed. All the doped samples showed better efficiency than pure ZnO, and Z1N was considered the best result, reaching 93.8% (MB) and 88% (CV) degradation after 25 minutes in front of the mixed dyes. For the antimicrobial properties, the samples were evaluated against E. coli and S. aureus bacteria. The Z2N sample showed the best results for S. aureus, even better than that of the control antibiotic. [Display omitted] •Nb-doped ZnO particles were successfully synthesized.•Orange-red emission was detected in PL analysis.•A practical applicability was estimated against a mixture of dyes under sunlight.•An increase in antimicrobial effect and photocatalytic was observed.