Although different NbO_(x) units are present in Nb_(2)O_(5)‐based catalysts,the correlations between these structures and activity remain unclear,which considerably hinders the further development of Nb_(2)O_(5) phot...Although different NbO_(x) units are present in Nb_(2)O_(5)‐based catalysts,the correlations between these structures and activity remain unclear,which considerably hinders the further development of Nb_(2)O_(5) photocatalysis.Herein,we utilized N‐hydroxyphthalimide(NHPI)as the probe molecule to distinguish the role of different NbO_(x) units in the activation of C–H bond under visible light irradia‐tion.With the addition of NHPI,Nb_(2)O_(5) catalysts with highly disordered NbO_(6) units exhibited higher activities than that with slightly disordered NbO_(6) units(419‒495 vs.82μmol·g^(-1)·h^(-1))in photocata‐lytic selective oxidation of ethylbenzene.Revealed by Raman spectra,electron paramagnetic reso‐nance spectra,and transmission‐electron‐microscopy images,highly disordered NbO_(6) units were confirmed to act as the active sites for the transfer of photogenerated electrons from NHPI,pro‐moting the generation of phthalimide‐N‐oxyl(PINO)radicals for the enhanced conversion of ethylbenzene under visible light irradiation.This study provides guidance on the role of local NbO_(x) units in Nb_(2)O_(5) photocatalysis.展开更多
The photovoltaic properties of dimeric porphyrin have been studied by means of surface photovoltage spectrum(SPS) and field induced surface photovoltage spectrum(FISPS). The results show that a negative SPV response b...The photovoltaic properties of dimeric porphyrin have been studied by means of surface photovoltage spectrum(SPS) and field induced surface photovoltage spectrum(FISPS). The results show that a negative SPV response band(P) appears in the long wave region which takes on n type character and the π π * transition band takes on p type character. P band disappears under high vacuum and appears under O 2 atmosphere. The photo charge transfer process generated between π π * transition band of dimeric porphyrin and P band, which has been attributed to the photo adsorption and photo desorption of O 2 on the surface of dimeric porphyrin.展开更多
Silica is commonly used as an ingredient in the coatings of inkjet papers because of its capability to provide a coating layer structure combining a high pore volume, into which all the applied inkjet ink can transfer...Silica is commonly used as an ingredient in the coatings of inkjet papers because of its capability to provide a coating layer structure combining a high pore volume, into which all the applied inkjet ink can transfer, and a suitable pore size distribution for very quick ink absorption. Nowadays, the production of silica pigment is quite expensive, and therefore, it would be advantageous to find a cheaper raw material source. In this study, the raw material was Greek olivine from magnesite mine sidestreams. The silica pigment was produced at laboratory scale by using nitric acid as a solvent. The target of this work was to clarify how this produced silica pigment is suited for inkjet coating pigments. The coating colors were applied by a laboratory rod coater on fine base paper and white-top kraftliner, and the coated surfaces were printed with a home and office area inkjet printer. The results showed that the produced olivine-based silica pigment has a potential in matt inkjet coatings. The coating of the produced silica pigment increased the print density, decreased the print-through, and diminished the bleeding of fine paper and white-top kraftliner board. However, further development work is needed to improve the pigment brightness to a more acceptable level, and to control the particle size at the nitric acid dissolution.展开更多
The luminescence behaviors of 4’-dimethyldrinoflavone derivarive with different structures have been studied in different conditions. Results show that the luminescence behavior depends dramatically on the solvent po...The luminescence behaviors of 4’-dimethyldrinoflavone derivarive with different structures have been studied in different conditions. Results show that the luminescence behavior depends dramatically on the solvent polarity. The reason is attributed to the different conformations in different solvents. The planar conformation is proved to be favorable to the fluorescence emission. In addition, results of viscosity-dependent luminescence property show that for compound 3 with the rigidized planar structure the luminescence behavior do not depend on the medium viscosity. But, for compound 1 and 2 the fluorescence quantum yields increase with increasing medium viscosity evidently,indicating that the rotation relaxation process of benzene ring in the molecule is yery important for the nonradiative decay process of excited molecules of compounds.展开更多
文摘Although different NbO_(x) units are present in Nb_(2)O_(5)‐based catalysts,the correlations between these structures and activity remain unclear,which considerably hinders the further development of Nb_(2)O_(5) photocatalysis.Herein,we utilized N‐hydroxyphthalimide(NHPI)as the probe molecule to distinguish the role of different NbO_(x) units in the activation of C–H bond under visible light irradia‐tion.With the addition of NHPI,Nb_(2)O_(5) catalysts with highly disordered NbO_(6) units exhibited higher activities than that with slightly disordered NbO_(6) units(419‒495 vs.82μmol·g^(-1)·h^(-1))in photocata‐lytic selective oxidation of ethylbenzene.Revealed by Raman spectra,electron paramagnetic reso‐nance spectra,and transmission‐electron‐microscopy images,highly disordered NbO_(6) units were confirmed to act as the active sites for the transfer of photogenerated electrons from NHPI,pro‐moting the generation of phthalimide‐N‐oxyl(PINO)radicals for the enhanced conversion of ethylbenzene under visible light irradiation.This study provides guidance on the role of local NbO_(x) units in Nb_(2)O_(5) photocatalysis.
文摘The photovoltaic properties of dimeric porphyrin have been studied by means of surface photovoltage spectrum(SPS) and field induced surface photovoltage spectrum(FISPS). The results show that a negative SPV response band(P) appears in the long wave region which takes on n type character and the π π * transition band takes on p type character. P band disappears under high vacuum and appears under O 2 atmosphere. The photo charge transfer process generated between π π * transition band of dimeric porphyrin and P band, which has been attributed to the photo adsorption and photo desorption of O 2 on the surface of dimeric porphyrin.
基金funding from the European Com-munity’s Seventh Framework Programme
文摘Silica is commonly used as an ingredient in the coatings of inkjet papers because of its capability to provide a coating layer structure combining a high pore volume, into which all the applied inkjet ink can transfer, and a suitable pore size distribution for very quick ink absorption. Nowadays, the production of silica pigment is quite expensive, and therefore, it would be advantageous to find a cheaper raw material source. In this study, the raw material was Greek olivine from magnesite mine sidestreams. The silica pigment was produced at laboratory scale by using nitric acid as a solvent. The target of this work was to clarify how this produced silica pigment is suited for inkjet coating pigments. The coating colors were applied by a laboratory rod coater on fine base paper and white-top kraftliner, and the coated surfaces were printed with a home and office area inkjet printer. The results showed that the produced olivine-based silica pigment has a potential in matt inkjet coatings. The coating of the produced silica pigment increased the print density, decreased the print-through, and diminished the bleeding of fine paper and white-top kraftliner board. However, further development work is needed to improve the pigment brightness to a more acceptable level, and to control the particle size at the nitric acid dissolution.
文摘The luminescence behaviors of 4’-dimethyldrinoflavone derivarive with different structures have been studied in different conditions. Results show that the luminescence behavior depends dramatically on the solvent polarity. The reason is attributed to the different conformations in different solvents. The planar conformation is proved to be favorable to the fluorescence emission. In addition, results of viscosity-dependent luminescence property show that for compound 3 with the rigidized planar structure the luminescence behavior do not depend on the medium viscosity. But, for compound 1 and 2 the fluorescence quantum yields increase with increasing medium viscosity evidently,indicating that the rotation relaxation process of benzene ring in the molecule is yery important for the nonradiative decay process of excited molecules of compounds.
