TY - JOUR
T1 - ZnO-graphene quantum dots heterojunctions for natural sunlight-driven photocatalytic environmental remediation
AU - Kumar, Suneel
AU - Dhiman, Ankita
AU - Sudhagar, Pitchaimuthu
AU - Krishnan, Venkata
N1 - Funding Information:
We are thankful to Advanced Materials Research Centre (AMRC), IIT Mandi for the characterization facilities. VK acknowledges the financial support from Department of Science and Technology (DST), India under SERB Young Scientist Scheme ( YSS/2014/000456/CS ). SK acknowledges research fellowship from University Grants Commission (UGC), India .
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/7/31
Y1 - 2018/7/31
N2 - In this work, we report the formation of heterojunctions comprising of graphene quantum dots (GQD) decorated ZnO nanorods (NR) and its use as efficient photocatalysts for environmental remediation. The heterojunctions has been designed to be active both in the UV and visible light regions and anticipated utilize the maximum part of the solar light spectrum. In this view, we examined the photocatalytic performance of our heterojunctions towards the degradation of colored pollutant (methylene blue (MB) dye) and a colorless pollutant (carbendazim (CZ) fungicide) under sunlight irradiation. Compared to bare photocatalyst ZnO and GQD, the heterojunction with 2 wt% of GQD (ZGQD2) showed the best photocatalytic activity by effectively degrading (about 95%) of organic pollutants (MB and CZ) from water within a short span of 70 min. The superior photocatalytic activity of these ZnO-GQD heterojunctions could be attributed to efficient charge carrier separation lead suppressed recombination rate at photocatalyst interfaces. In addition to the enhanced light absorption from UV to visible region, the high specific surface area of ZGQD2 heterojunction (353.447 m 2 g −1 ) also imparts strong adsorption capacity for pollutants over catalyst surface, resulting in high photoactivity. Based on the obtained results, band gap alignment at ZnO-GQD heterojunction and active species trapping experiments, a plausible mechanism is proposed for photocatalytic reaction. The excellent photostability and recyclability of the ZnO-GQD heterojunctions fostering as promising photocatalyst candidate for environmental remediation applications.
AB - In this work, we report the formation of heterojunctions comprising of graphene quantum dots (GQD) decorated ZnO nanorods (NR) and its use as efficient photocatalysts for environmental remediation. The heterojunctions has been designed to be active both in the UV and visible light regions and anticipated utilize the maximum part of the solar light spectrum. In this view, we examined the photocatalytic performance of our heterojunctions towards the degradation of colored pollutant (methylene blue (MB) dye) and a colorless pollutant (carbendazim (CZ) fungicide) under sunlight irradiation. Compared to bare photocatalyst ZnO and GQD, the heterojunction with 2 wt% of GQD (ZGQD2) showed the best photocatalytic activity by effectively degrading (about 95%) of organic pollutants (MB and CZ) from water within a short span of 70 min. The superior photocatalytic activity of these ZnO-GQD heterojunctions could be attributed to efficient charge carrier separation lead suppressed recombination rate at photocatalyst interfaces. In addition to the enhanced light absorption from UV to visible region, the high specific surface area of ZGQD2 heterojunction (353.447 m 2 g −1 ) also imparts strong adsorption capacity for pollutants over catalyst surface, resulting in high photoactivity. Based on the obtained results, band gap alignment at ZnO-GQD heterojunction and active species trapping experiments, a plausible mechanism is proposed for photocatalytic reaction. The excellent photostability and recyclability of the ZnO-GQD heterojunctions fostering as promising photocatalyst candidate for environmental remediation applications.
KW - Charge transfer
KW - Environmental remediation
KW - Graphene quantum dots
KW - Heterojunctions
KW - Photocatalysis
KW - ZnO
UR - http://www.scopus.com/inward/record.url?scp=85045263763&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2018.04.045
DO - 10.1016/j.apsusc.2018.04.045
M3 - Article
AN - SCOPUS:85045263763
SN - 0169-4332
VL - 447
SP - 802
EP - 815
JO - Applied Surface Science
JF - Applied Surface Science
ER -