TY - JOUR
T1 - Nitrogen and Sulfur Co-Doped Graphene Quantum Dots Anchored TiO2 Nanocomposites for Enhanced Photocatalytic Activity
AU - Rawal, Jishu
AU - Kamran, Urooj
AU - Park, Mira
AU - Pant, Bishweshwar
AU - Park, Soo Jin
N1 - Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/5
Y1 - 2022/5
N2 - Herein, nitrogen (N) and sulfur (S) co-doped graphene quantum dots (GQDs) using different one-dimensional (1-D) carbon nanomaterials as precursors were synthesized, followed by heterojunction formation with TiO2. GQDs exhibit unlike physiochemical properties due to the disproportionate ratio of N and S heteroatoms and dissimilar reaction parameters. Tailored type-II band gap (Eg) alignment was formed with narrowed Eg value that improves photogenerated electron transfer due to π-conjugation. GQDs-TiO2 nanocomposites exhibit remarkably high methylene blue (MB) degradation up to 99.78% with 2.3–3 times elevated rate constants as compared with TiO2. CNF-GQDs-TiO2 demonstrates the fastest MB degradation (60 min) due to the synergistic effect of nitrogen and sulfur doping, and is considered the most stable photocatalyst among prepared nanocomposites as tested up to three cyclic runs. Whereas, C–O–Ti bonds were not only responsible for nanocomposites strengthening but also provide a charge transfer pathway. Moreover, charge transport behavior, generation of active species, and reaction mechanism were scrutinized via free-radical scavenger analysis.
AB - Herein, nitrogen (N) and sulfur (S) co-doped graphene quantum dots (GQDs) using different one-dimensional (1-D) carbon nanomaterials as precursors were synthesized, followed by heterojunction formation with TiO2. GQDs exhibit unlike physiochemical properties due to the disproportionate ratio of N and S heteroatoms and dissimilar reaction parameters. Tailored type-II band gap (Eg) alignment was formed with narrowed Eg value that improves photogenerated electron transfer due to π-conjugation. GQDs-TiO2 nanocomposites exhibit remarkably high methylene blue (MB) degradation up to 99.78% with 2.3–3 times elevated rate constants as compared with TiO2. CNF-GQDs-TiO2 demonstrates the fastest MB degradation (60 min) due to the synergistic effect of nitrogen and sulfur doping, and is considered the most stable photocatalyst among prepared nanocomposites as tested up to three cyclic runs. Whereas, C–O–Ti bonds were not only responsible for nanocomposites strengthening but also provide a charge transfer pathway. Moreover, charge transport behavior, generation of active species, and reaction mechanism were scrutinized via free-radical scavenger analysis.
KW - free radical generation
KW - graphene quantum dots
KW - nanocomposites
KW - photocatalytic degradation
UR - http://www.scopus.com/inward/record.url?scp=85130152984&partnerID=8YFLogxK
U2 - 10.3390/catal12050548
DO - 10.3390/catal12050548
M3 - Article
AN - SCOPUS:85130152984
SN - 2073-4344
VL - 12
JO - Catalysts
JF - Catalysts
IS - 5
M1 - 548
ER -