The modification of graphitic carbon nitride can significantly improve the photocatalytic performance of graphitic carbon nitride(g-C3N4).Fe2O3/nitrogen-deficient g-C3N4-x composite catalysts were prepared with dicyan...The modification of graphitic carbon nitride can significantly improve the photocatalytic performance of graphitic carbon nitride(g-C3N4).Fe2O3/nitrogen-deficient g-C3N4-x composite catalysts were prepared with dicyandiamide as the precursor and Fe3+doped in this study.The composite catalysts were characterized by XRD,SEM,FT-IR,XPS and photocurrent measurements.Close interaction occurred between Fe2O3 and nitrogen deficient g-C3N4-x,more photogenerated electrons were created and effectively separated from the holes,resulting in a decrease of photocarrier recombination,and thus enhancing the photocurrent.Photocatalytic performance experiments showed that Fe2O3/nitrogen deficient g-C3N4-x could utilize lowenergy visible light more efficiently than pure g-C3N4,and the removal rate was 92%in 60 minutes.展开更多
Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the ...Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the pre-formed Au/g-C_3N_4 for photocatalytic hydrogen evolution. Their structure, morphology and optical property were investigated in detail. Photocatalytic activities of the developed photocatalysts for water splitting were evaluated under visible-light irradiation(k > 420 nm) using glucose as electron donor.The highest hydrogen evolution rate of 123 lmol g^(-1)h^(-1)is achieved by Cd_(0.8Z)n_(0.2)S/Au/g-C_3N_4, which is 52.2 and 8.63 times higher than that of Au/g-C_3N_4 and Cd S/Au/g-C_3N_4, respectively. The results of photoluminescence spectra, photoelectrochemical and time-resolved photoluminescence spectra indicate that the improved photocatalytic activities for Cd_xZn_(1-x)S/Au/g-C_3N_4 are due to the efficient separation of photogenerated carriers. In addition, it is noteworthy that the undesired byproducts CO and CO_2 are greatly reduced by introducing CdxZn_(1-x)S over Au/g-C_3N_4 surface. In the photocatalytic process, gluconic acid originated from the reaction of photogenerated hydroxyl radical with glucose plays a vital role on suppressing the formation of the gas byproducts. The present work will provide a new strategy to design Z-scheme photocatalysts with enhanced efficiency for water splitting along with suppressing the byproducts.展开更多
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 opt...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.展开更多
基金Supported by the Fuling Shale Gas Environmental Exploration Technology of National Science and Technology Special Project(No.2016ZX05060)the Demonstration of Integrated Management of Rocky Desertification and Enhancement of Ecological Service Function in Karst Peak-cluster Depression(No.2016YFC0502400)National Natural Science Foundation of China(No.51709254)
文摘The modification of graphitic carbon nitride can significantly improve the photocatalytic performance of graphitic carbon nitride(g-C3N4).Fe2O3/nitrogen-deficient g-C3N4-x composite catalysts were prepared with dicyandiamide as the precursor and Fe3+doped in this study.The composite catalysts were characterized by XRD,SEM,FT-IR,XPS and photocurrent measurements.Close interaction occurred between Fe2O3 and nitrogen deficient g-C3N4-x,more photogenerated electrons were created and effectively separated from the holes,resulting in a decrease of photocarrier recombination,and thus enhancing the photocurrent.Photocatalytic performance experiments showed that Fe2O3/nitrogen deficient g-C3N4-x could utilize lowenergy visible light more efficiently than pure g-C3N4,and the removal rate was 92%in 60 minutes.
基金supported by the National Natural Science Foundation of China (51672089)the Industry and Research Collaborative Innovation Major Projects of Guangzhou (201508020098)+1 种基金the State Key Laboratory of Advanced Technology for Material Synthesis and Processing (Wuhan University of Technology) (2015-KF-7)the Hunan Key Laboratory of Applied Environmental Photocatalysis (Changsha University) (CCSU-XT-04)~~
基金supported by the National Natural Science Foundation of China (U1403193 and 21643012)the ‘‘Western Light” Program (YB201303)the Outstanding Young Scientist Program of Chinese Academy of Sciences
文摘Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the pre-formed Au/g-C_3N_4 for photocatalytic hydrogen evolution. Their structure, morphology and optical property were investigated in detail. Photocatalytic activities of the developed photocatalysts for water splitting were evaluated under visible-light irradiation(k > 420 nm) using glucose as electron donor.The highest hydrogen evolution rate of 123 lmol g^(-1)h^(-1)is achieved by Cd_(0.8Z)n_(0.2)S/Au/g-C_3N_4, which is 52.2 and 8.63 times higher than that of Au/g-C_3N_4 and Cd S/Au/g-C_3N_4, respectively. The results of photoluminescence spectra, photoelectrochemical and time-resolved photoluminescence spectra indicate that the improved photocatalytic activities for Cd_xZn_(1-x)S/Au/g-C_3N_4 are due to the efficient separation of photogenerated carriers. In addition, it is noteworthy that the undesired byproducts CO and CO_2 are greatly reduced by introducing CdxZn_(1-x)S over Au/g-C_3N_4 surface. In the photocatalytic process, gluconic acid originated from the reaction of photogenerated hydroxyl radical with glucose plays a vital role on suppressing the formation of the gas byproducts. The present work will provide a new strategy to design Z-scheme photocatalysts with enhanced efficiency for water splitting along with suppressing the byproducts.
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）.
文摘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.
