Impact of calcined temperatures on the crystalline parameters, morphological, energy band gap, electrochemical, antimicrobial, antioxidant, and hemolysis behavior of nanocrystalline tin oxide

To construct a battery, the precipitation-synthesized SnO₂ products at 450 °C and 650 °C were separately taken and mixed with graphite as the anode and PbO₂,V₂O_5, and graphite materials as cathode materials to make the pellets and examine their open circuit voltage (OCV) values. The microstrain, lattice parameter, and crystallite size values of the above-mentioned tin oxide compounds were obtained through Rietveld refinement-MAUD fit analysis. The microstrain and lattice parameter values of tin oxide were significantly varied at a higher calcined temperature. Surface particle grain growth was increased with the increased calcined temperature from 450 to 650 °C as evidenced by FE-SEM study. Particle size distributions of SnO₂ and polycrystalline behavior have been discussed with the aid of TEM analysis. From the UV–visible spectra, optical band gap (E_g) values reduced from 3.73 to 3.69 eV for the SnO₂ products with an increase in calcined temperatures from 450 to 650 °C. The antimicrobial responses of the two different calcined SnO₂ samples at 450 °C and 650 °C against two different bacterial pathogens (gram-positive-S. aureus and gram-negative-E.coli) were investigated. From the microbicidal assessment, a relatively higher diameter of the zone of inhibition (DZOI) of tin oxide at 650 °C samples was measured to be 19 ± 2 mm and 21 ± 2 mm for S. aureus and E. Coli than the DZOI of SnO₂ at 450 °C samples (15 ± 1 mm for S. aureus and 18 ± 1 mm for E. coli. DPPH scavenging activity at 100 μg/ml shows that SnO₂ calcined at 450 °C achieves 68 ± 1 %, while SnO₂ calcined at 650 °C exhibits a significantly higher activity of 86 ± 1 %. A slight increase in hemolysis was observed for SnO₂ calcined at 650 °C, reaching 1.3 % at higher concentrations, but overall, hemolysis remained below 5 %, indicating high hemocompatibility.