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Remarkable Improvement in Photocatalytic Performance for Tannery Wastewater Processing via SnS 2 Modified with N‐Doped Carbon Quantum Dots: Synthesis, Characterization, and 4‐Nitrophenol‐Aided Cr(VI) Photoreduction
Author(s) -
Wang Shuo,
Li Liping,
Zhu Zhenghui,
Zhao Minglei,
Zhang Liming,
Zhang Nannan,
Wu Qiannan,
Wang Xiyang,
Li Guangshe
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201804515
Subject(s) - photocatalysis , materials science , x ray photoelectron spectroscopy , doping , charge carrier , zeta potential , chemical engineering , band gap , quantum efficiency , dielectric spectroscopy , electrochemistry , photochemistry , nanotechnology , nanoparticle , catalysis , optoelectronics , chemistry , electrode , organic chemistry , engineering
Photocatalytic pathways are proved crucial for the sustainable production of chemicals and fuels required for a pollution‐free planet. Electron–hole recombination is a critical problem that has, so far, limited the efficiency of the most promising photocatalytic materials. Here, the efficacy of the 0D N doped carbon quantum dots (N‐CQDs) is demonstrated in accelerating the charge separation and transfer and thereby boosting the activity of a narrow‐bandgap SnS 2 photocatalytic system. N‐CQDs are in situ loaded onto SnS 2 nanosheets in forming N‐CQDs/SnS 2 composite via an electrostatic interaction under hydrothermal conditions. Cr(VI) photoreduction rate of N‐CQDs/SnS 2 is highly enhanced by engineering the loading contents of N‐CQDs, in which the optimal N‐CQDs/SnS 2 with 40 mol% N‐CQDs exhibits a remarkable Cr(VI) photoreduction rate of 0.148 min −1 , about 5‐time and 148‐time higher than that of SnS 2 and N‐CQDs, respectively. Examining the photoexcited charges via zeta potential, X‐ray photoelectron spectroscopy (XPS), surface photovoltage, and electrochemical impedance spectra indicate that the improved Cr(VI) photodegradation rate is linked to the strong electrostatic attraction between N‐CQDs and SnS 2 nanosheets in composite, which favors efficient carrier utilization. To further boost the carrier utilization, 4‐nitrophenol is introduced in this photocatalytic system and the efficiency of Cr(VI) photoreduction is further promoted.