摘要
Novel SnO2-x/g-C3N4 heterojunction nanocomposites composed of reduced SnO2 nanoparticles and exfoliated g-CBN4 nanosheets were prepared by a convenient one-step pyrolysis method. The structural, morphological, and optical properties of the as-prepared nanocomposites were characterized in detail, indicating that the aggregation of g-C3N4 nanosheets was prevented by small, well-dispersed SnO2_x nanoparticles. The ultraviolet-visible spectroscopy absorption bands of the nanocomposites were shifted to a longer wavelength region than those exhibited by pure SnO2 or g-CgN4. The charge transfer and recombination processes occurring in the nanocomposites were investigated using linear scan voltammetry and electrochemical impedance spectroscopy. Under 30-W visible-light-emitting diode irradiation, the heterojunction containing 27.4 wt.% SnO2-x exhibited the highest photocurrent density of 0.0468 mA.cm-2, which is 33.43 and 5.64 times larger than that of pure SnO2 and g-C3N4, respectively. The photocatalytic activity of the heterojunction material was investigated by degrading rhodamine B under irradiation from the same light source. Kinetic study revealed a promising degradation rate constant of 0.0226 min^-1 for the heterojunction containing 27.4 wt.% SnO2-x, which is 32.28 and 5.79 times higher than that of pure SnO2 and g-C3N4, respectively. The enhanced photoelectrochemical and photocatalytic performances of the nanocomposite may be due to its appropriate SnO2x content and the compact structure of the junction between the SnO2-x nanoparticles and the g-C3N4 nanosheets, which inhibits the recombination of photogenerated electrons and holes.
Novel SnO2-x/g-C3N4 heterojunction nanocomposites composed of reduced SnO2 nanoparticles and exfoliated g-CBN4 nanosheets were prepared by a convenient one-step pyrolysis method. The structural, morphological, and optical properties of the as-prepared nanocomposites were characterized in detail, indicating that the aggregation of g-C3N4 nanosheets was prevented by small, well-dispersed SnO2_x nanoparticles. The ultraviolet-visible spectroscopy absorption bands of the nanocomposites were shifted to a longer wavelength region than those exhibited by pure SnO2 or g-CgN4. The charge transfer and recombination processes occurring in the nanocomposites were investigated using linear scan voltammetry and electrochemical impedance spectroscopy. Under 30-W visible-light-emitting diode irradiation, the heterojunction containing 27.4 wt.% SnO2-x exhibited the highest photocurrent density of 0.0468 mA.cm-2, which is 33.43 and 5.64 times larger than that of pure SnO2 and g-C3N4, respectively. The photocatalytic activity of the heterojunction material was investigated by degrading rhodamine B under irradiation from the same light source. Kinetic study revealed a promising degradation rate constant of 0.0226 min^-1 for the heterojunction containing 27.4 wt.% SnO2-x, which is 32.28 and 5.79 times higher than that of pure SnO2 and g-C3N4, respectively. The enhanced photoelectrochemical and photocatalytic performances of the nanocomposite may be due to its appropriate SnO2x content and the compact structure of the junction between the SnO2-x nanoparticles and the g-C3N4 nanosheets, which inhibits the recombination of photogenerated electrons and holes.
基金
This work was supported by the Key Project of Natural Science Foundation of Shandong Province （No. ZR2013EMZ001）, the Science and Technology Development Plan Project of Shandong Province （No. 2014GSF117015）, the National Basic Research Program of China （No. 2013CB632401） and the National Natural Science Foundation of China （No. 51402145）. This work was also supported by the U.S. Department of Energy under Contract DE-AC0206CH11357 with the main support provided by the Vehicle Technologies Office, Department of Energy （DOE） Office of Energy Efficiency and Renewable Energy （EERE）.
