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Nano Research

Article Title

Ultrasonic-assisted pyrolyzation fabrication of reduced SnO2–x /g-C3N4 heterojunctions: Enhance photoelectrochemical and photocatalytic activity under visible LED light irradiation

Keywords

reduced SnO2–x, g-C3N4, heterojunctions, photoelectrochemical, light-emitting diode lightsource

Abstract

Novel SnO2–x/g-C3N4 heterojunction nanocomposites composed of reduced SnO2–xnanoparticles and exfoliated g-C3N4 nanosheets were prepared by a convenientone-step pyrolysis method. The structural, morphological, and optical propertiesof the as-prepared nanocomposites were characterized in detail, indicating thatthe aggregation of g-C3N4 nanosheets was prevented by small, well-dispersedSnO2–x nanoparticles. The ultraviolet–visible spectroscopy absorption bands of thenanocomposites were shifted to a longer wavelength region than those exhibitedby pure SnO2 or g-C3N4. The charge transfer and recombination processes occurringin the nanocomposites were investigated using linear scan voltammetry andelectrochemical impedance spectroscopy. Under 30-W visible-light-emittingdiode irradiation, the heterojunction containing 27.4 wt.% SnO2–x exhibited thehighest photocurrent density of 0.0468 mA·cm–2, which is 33.43 and 5.64 timeslarger than that of pure SnO2 and g-C3N4, respectively. The photocatalytic activityof the heterojunction material was investigated by degrading rhodamine B underirradiation from the same light source. Kinetic study revealed a promisingdegradation rate constant of 0.0226 min−1 for the heterojunction containing27.4 wt.% SnO2–x, which is 32.28 and 5.79 times higher than that of pure SnO2 andg-C3N4, respectively. The enhanced photoelectrochemical and photocatalyticperformances of the nanocomposite may be due to its appropriate SnO2–x contentand the compact structure of the junction between the SnO2–x nanoparticles andthe g-C3N4 nanosheets, which inhibits the recombination of photogeneratedelectrons and holes.

Graphical Abstract

Publisher

Tsinghua University Press

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