Role of carbon quantum dots in a strategic approach to prepare pristine Zn2SnO4 and enhance photocatalytic activity under direct sunlight

In the present work, carbon quantum dots (CQDs) are used in a strategic approach to obtain pristine mesoporous Zn2SnO4 (ZTO) and enhanced photodegradation of methylene blue (MB) dye. The Zn2SnO4/carbon quantum dots (ZTO/C) was hydrothermally prepared using mineralizer, Na2CO3 and quantified amount of sugarcane juice. The mesoporous nature and high surface area of ZTO and ZTO/C was revealed from Brunauer, Emmett and Teller (BET). The close overlapping of CQD with ZTO was evident from the HRTEM and Raman spectra. The MB dye degradation study employing ZTO and ZTO/C catalyst under direct sunlight irradiation showed 84 % and 95 % degradation in 150 min respectively. The presence of CQDs in ZTO/C nanocomposites enhanced the transportation of photoinduced electrons at the interface between ZTO and CQDs, whereas holes stayed in the valence band of ZTO, suppressing the recombination of photogenerated charge carriers during photocatalysis. This study reveals that ZTO/C as a possible candidate for sunlight-driven photocatalysis and environmental remediation.