Preparation of SiO₂-Coated TiO₂ Composite Materials with Enhanced Photocatalytic Activity Under UV Light

Hu, Shaozheng,Li, Fayun,Fan, Zhiping Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

$SiO_2$-coated $TiO_2$ composite materials with enhanced photocatalytic activity under UV light was prepared by a simple catalytic hydrolysis method. XRD, TEM, UV-vis spectroscopy, Photoluminescence, FT-IR and XP spectra were used to characterize the prepared samples. The obvious shell-core structure was shown for obtained $SiO_2$@$TiO_2$ sample. The average thickness of the $SiO_2$ coating layer was 2-3 nm. The interaction between $SiO_2$ and $TiO_2$ restrained the recombination of excited electrons and holes. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under UV light. The photocatalytic activity of $SiO_2$@$TiO_2$ was much higher than that of P25 and mechanical mixing sample $SiO_2/TiO_2$. The possible mechanism for the photocatalysis was proposed.

Enhanced Visible Light Activity and Stability of TiO2 Nanopowder by co-doped with Mo and N

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.4

A visible light responsive N, Mo co-doped TiO2 were prepared by sol-gel method. X-ray diffraction, TEM, N2 adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO2 samples. Doping restrained the phase transformation from anatase to rutile and reduced the particle sizes. The band gap was much narrowed after N, Mo co-doping. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of doped TiO2 were much higher than that of neat TiO2. The photocatalytic stability of N, Mo co-doped TiO2 was much better than that of N doped TiO2.

The Synergistic Effect of Nitrogen and Ni2O3 over TiO2 Photocatalyst in the Degradation of 2,4,6-Trichlorophenol under Visible Light

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

The composite photocatalyst, N-TiO2 loaded with Ni2O3, was prepared by N2 plasma treatment. X-ray diffraction, X-ray fluorescence, N2 adsorption, UV-vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO2 samples. The results indicated that the band gap energy was decreased obviously by nitrogen doping, whereas loading of Ni2O3 did not influence the band gap and visible light absorption. The photocatalytic activities were tested in the degradation of 2,4,6- trichlorophenol (TCP) under visible light. The photocatalytic activity and stability of composite photocatalyst were much higher than that of catalyst modified with nitrogen or Ni2O3 alone. The synergistic effect of doping nitrogen and Ni2O3 over TiO2 was investigated.

Practical Preparation of Carbon Black/Carbon Nitride Compounds and Their Photocatalytic Performance

Shaozheng Hu,Haoying Wang,Fei Wang,Jin Bai,Lei Zhang,Xiaoxue Kang,GuangWu 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.10

Here we report a carbon-black-modified g-C3N4 nanocomposite prepared by a convenient method and its photocatalytic performance, which was compared with other carbon-material-, carbon nanotube (CNT)-, C60-, and graphene (GR)-modified g-C3N4 nanocomposites. X-ray diffraction, N2 adsorption, UV–vis spectroscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and photoluminescence were used to characterize the prepared composite material. The results reveal that incorporating g-C3N4 with carbon materials decreases the bandgap and the electron–hole recombination rate of the prepared catalysts. No significant difference was observed in the structural and optical properties among these four series of carbon-material-modified g-C3N4 nanocomposites. Carbon-based materials cannot act as visible-light sensitizers but they can facilitate the separation and transport of photogenerated carriers. These composites obey a tentative reaction mechanism similar to rhodamine B (RhB) photocatalytic degradation. Carbon-black-modified g-C3N4 exhibits comparable activity and stability as those of GR-modified g-C3N4 , which is better than the modification by C60 and CNTs. Compared to CNTs, GR, and C60 , carbon black is a cheap and effective carbon source with excellent photocatalytic performance for the preparation of carbon material/g-C3N4 nanocomposites.

Preparation of Dihydroxy Naphthalene/TiO2 Complex via Surface Modification and Their Photocatalytic H2 Production Performances Under Visible Light

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.7

The dihydroxy naphthalene/TiO2 complexes with different substitution patterns were prepared by surface modification. X-ray diffraction, UV-Vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared composite materials. The results indicated that the surface modification did not influence the crystallization of TiO2. The visible-light absorbances of prepared dihydroxy naphthalene/TiO2 complexes could be assigned to the ligand-to-metal charge transfer. The obtained catalyst exhibited outstanding photocatalytic activity and stability under visible light. A linear relationship existed between the percentages of hydroxynaphthalenes coordinated on TiO2 surface and H2 production ability. The substitution pattern of dihydroxy naphthalene and CH3OH content could also influence the photocatalytic performance remarkably. The photocatalytic H2 production ability was further improved after loading with ultra low concentration of Pt, 0.02 wt %. The possible mechanism was proposed.

The Property and Photocatalytic Performance Comparison of Graphene, Carbon Nanotube, and C60 Modified TiO2 Nanocomposite Photocatalysts

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

A series of carbon nanotube, C60, and graphene modified TiO2 nanocomposites were prepared by hydrothermal method. X-ray diffraction, N2 adsorption, UV-Vis spectroscopy, photoluminescence, and Electrochemical impedance spectra were used to characterize the prepared composite materials The results reveal that incorporating TiO2 with carbon materials can extend the adsorption edge of all the TiO2-carbon nanocomposites to the visible light region. The photocatalytic activities were tested in the degradation of 2,4,6-trichlorophenol (TCP) under visible light. No obvious difference in essence was observed in structural and optical properties among three series of carbon modified TiO2 nanocomposites. Three series of carbon materials modified TiO2 composites follow the analogous tentative reaction mechanism for TCP degradation. GR modified TiO2 nanocomposite exhibits the strongest interaction and the most effective interfacial charge transfer among three carbon materials, thus shows the highest electron-hole separation rate, leading to the highest photocatalytic activity and stability.

Preparation of SiO2-Coated TiO2 Composite Materials with Enhanced Photocatalytic Activity Under UV Light

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.6

SiO2-coated TiO2 composite materials with enhanced photocatalytic activity under UV light was prepared by a simple catalytic hydrolysis method. XRD, TEM, UV-vis spectroscopy, Photoluminescence, FT-IR and XP spectra were used to characterize the prepared samples. The obvious shell-core structure was shown for obtained SiO2@TiO2 sample. The average thickness of the SiO2 coating layer was 2-3 nm. The interaction between SiO2 and TiO2 restrained the recombination of excited electrons and holes. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under UV light. The photocatalytic activity of SiO2@TiO2 was much higher than that of P25 and mechanical mixing sample SiO2/TiO2. The possible mechanism for the photocatalysis was proposed.

The Comparison of Property and Visible Light Activity between Bulk and Surface Doped N-TiO2 Prepared by Sol-gel and N2-plasma Treatment

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.1

A modified sol-gel method and N2-plasma treatment were used to prepare bulk and surface doped N-TiO2,respectively. XRD, TEM, UV-vis spectroscopy, N2 adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared TiO2 samples. The N doping did not change the phase composition and particle sizes of TiO2 samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N-TiO2 prepared by N2-plasma was much higher than that of bulk doped N-TiO2 prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.

The Property and Photocatalytic Performance Comparison of Graphene, Carbon Nanotube, and C₆₀ Modified TiO₂ Nanocomposite Photocatalysts

Hu, Shaozheng,Li, Fayun,Fan, Zhiping Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.12

A series of carbon nanotube, $C_{60}$, and graphene modified $TiO_2$ nanocomposites were prepared by hydrothermal method. X-ray diffraction, $N_2$ adsorption, UV-Vis spectroscopy, photoluminescence, and Electrochemical impedance spectra were used to characterize the prepared composite materials The results reveal that incorporating $TiO_2$ with carbon materials can extend the adsorption edge of all the $TiO_2$-carbon nanocomposites to the visible light region. The photocatalytic activities were tested in the degradation of 2,4,6-trichlorophenol (TCP) under visible light. No obvious difference in essence was observed in structural and optical properties among three series of carbon modified $TiO_2$ nanocomposites. Three series of carbon materials modified $TiO_2$ composites follow the analogous tentative reaction mechanism for TCP degradation. GR modified $TiO_2$ nanocomposite exhibits the strongest interaction and the most effective interfacial charge transfer among three carbon materials, thus shows the highest electron-hole separation rate, leading to the highest photocatalytic activity and stability.

A Convenient Method to Prepare Ag Deposited N-TiO2 Composite Nanoparticles via NH3 Plasma Treatment

Shaozheng Hu,Fayun Li,Zhiping Fan 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.7

Ag deposited N-TiO2 composite nanoparticles were prepared via NH3 plasma treatment. X-ray diffraction, UVvis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared TiO2 samples. The plasma treatment did not change the phase composition and particle sizes of TiO2 samples, but extended its absorption edges to the visible light region. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activities of Ag deposited N-TiO2 composite nanoparticles were much higher than Ag-TiO2, NTiO2, and P25. A possible mechanism for the photocatalysis was proposed.