Green synthesis of SnO2 quantum dots using Parkia speciosa Hassk pods extract for the evaluation of anti-oxidant and photocatalytic properties

In the present study, microwave heating method was established for the biosynthesis of SnO2 Quantum dots (QDs) using Parkia speciosa Hassk pods extract. The as-synthesized quantum dots have been characterized by various techniques such as UV, XRD, EDX, TEM, HRTEM, SAED and FTIR spectroscopy. The biosynthesized SnO2 QDs was employed for the first time as an efficient photocatalyst for the degradation of a food dye, acid yellow 23 dye from aqueous phase under the UV254 light. Various parameters, such as the effect of catalyst dose, the initial concentration of acid yellow 23 dye (AY23), pH of the solution and irradiation time on the photodegradation process are also studied for efficient and better use of the synthesized SnO2 QDs as a catalyst. The biosynthesized SnO2 QDs exhibited excellent photocatalytic performances with degradation efficiency 98% on the degradation of an aqueous solution of AY23 of concentration 5 mg/L with a catalyst dose of 20 mg under UV254 light within 24 min. The synthesized SnO2 QDs can be reused up to 5 cycles of photodegradation experiment without losing its stability and efficiency. The biosynthesized SnO2 QDs also shows a fair activity in the scavenging of 2,2-diphenyl-1-picrylhydrazyl free radical with the IC50 value of 312.6 ± 0.025 μg/mL.