余家国
纳米二氧化钛基半导体光催化材料、一维纳米结构材料、材料的仿生合成与形貌控制等
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- 姓名:余家国
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学术头衔:
博士生导师
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学科领域:
材料科学基础学科
- 研究兴趣:纳米二氧化钛基半导体光催化材料、一维纳米结构材料、材料的仿生合成与形貌控制等
余家国: 男,博士, 教授,博士生导师。1985年本科毕业于华中师范大学化学系,1988年硕士毕业于西安交通大学化学与化工学院,2000年武汉理工大学在职博士研究生毕业, 获工学博士学位。2000至2002和2003至2004年在香港中文大学化学系从事博士后研究工作。2001年晋升为博士生导师,同年成为享受国务院政府特殊津贴的专家。近几年在纳米二氧化钛基半导体光催化材料、一维纳米结构材料、材料的仿生合成与形貌控制等方面开展研究工作,多篇研究论文发表在多种国际著名刊物(sci影响因子大于3)如:j. am. chem. soc.、chem. mater.、 chem. commun.、j. phys. chem. b、appl. cata. b、j. catal.、langmuir,environ. sci. tech.等上。共发表论文130余篇,其中国际刊物论文60余篇,论文被sci收录76篇,ei收录63篇,被sci他人引文350次,4篇论文被isi评为近十年高引频论文。获得国家发明专利7项,湖北省自然科学一等奖一项(排名第二)、湖北省科技成果推广二等奖一项(第一)、湖北省科技进步二等奖一项(第二)、中国建筑材料工业协会发明二等奖一项(第二)。湖北省科技进步三等奖二项(第一)。最近主持的项目有国家自然科学基金面上项目(2项)、教育部优秀青年教师资助计划、中国-希腊科技合作项目(2002-2005年)、教育部留学回国人员科研启动基金资助项目等。担任多种国内外知名杂志的论文评阅人。
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2005-03-29
余家国, jiaguo yu*, xiujian zhao, qingnan zhao
thin solid films 379(2000)7-14,-0001,():
-1年11月30日
tio2 thin films with different surface structures are prepared from alkoxide solutions containing polyethylene glycol peg.via the sol-gel method. the effects of peg addition to the precursor solution on the surface structures and photocatalytic activity of the resultant thin films are studied. the larger the amount of peg added to the precursor solution, the larger the size and number of pores produced in the resultant films when peg added to the gel films decomposed completely during heat-treatment. the adsorbed hydroxyl content of such porous thin films is found to increase with increasing amount of peg. however, the transmittance of the films decreases due to the scattering of light by pores of larger size and bigger number in the films. photocatalytic degradation experiments show that methyl orange is efficiently decolorized in the presence of the tio2 thin films by exposing its aqueous solution to ultraviolet light and the suitable surface structures remarkably enhance the photocatalytic activity of tio2 films.
titanium oxide, coatings, catalysis, x-ray photoelectron spectroscopy xps.,
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2005-03-29
余家国, yu jiaguo, yu jimmy c., cheng bei t & zhao xiujian
science in china (series b), december 2003, vol. 46 no.6,-0001,():
-1年11月30日
highly photoactive bi-phase nanocrystalline tio2 photocatalyst was prepared by a solvent evaporation-induced crystallization (seic) method, and calcined at different temperatures. the obtained tio2 photocatalyst was characterized with x-ray diffraction (xrd), transmission elec-tron microscopy (tem) and bet surface areas. the photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. the results show that solvent evaporation can promote the crystallization and phase transformation of rio2 at 100℃. when calcination temperatures are below 600℃, the prepared tio2 powders show bimodal pore size distributions in the mesoporous region. at 700℃, the pore size distributions exhibit monomodal distribution of the inter-aggregated pores due to the collapse of the intra-aggregated pores. at 100℃, the obtained tio2 photocatalyst by this method shows good photocatalytic activity, and at 400℃, its photocatalytic activity exceeds that of degussa p25. this may be attributed to the fact that the prepared tio2 photocatalyst has higher specific surface areas, smaller crystallite size and bimodal pore size distribution.
nanocrystalline,, tio2,, photocatalyst,, preparation,, solvent evaporation-induced crystallization method.,
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2005-03-29
余家国, jiaguo yu*, jimmy c. yu, bei cheng and xiujian zhao
journal of sol-gel science and technology 24, 39-48, 2002,-0001,():
-1年11月30日
red on a soda-lime glass substrate by sol-gel dip-coating technique using tio2 sols containing lead(ii) nitrate. the thin films were characterized by x-ray photoelectron spectroscopy (xps), atomic force microscopy (afm), uv-vis spectroscopy and x-ray diffraction (xrd). a shift of the uv-vis absorption towards longer wavelengths was observed, which indicated a decrease in the band-gap of tio2 upon pb doping. xrd results showed both pure and pb-doped tio2 thin films were polycrystalline, anatase type, and oriented predominantly to the (101) plane. a slight shift in the d-spacing for the pb-doped film indicated the incorporation of pb into the tio2 lattice to form pbx ti1−xo2 solid solution. afm results showed pb-doped tio2 thin films were composed of larger tio2 particles and had rougher surface, compared with un-doped tio2 thin films. xps results showed that except for the enrichment of pb near the surface, pb exists in the forms of pbx ti1−xo2 and pbo. dimethyl-2,2-dichlorovinyl phosphate (ddvp) was efficiently degraded in the presence of the pb-doped tio2 thin films by exposing the insecticide solution to sunlight. the mechanism of photocatalytic activity enhancement of the pb-doped tio2 thin films was discussed.
sol-gel method,, pb-doped tio2 thin films,, characterization,, photocatalytic activity,, sunlight
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2005-03-29
余家国, jiaguo yu, a, b jimmy c. yu, *a wingkei ho a and zitao jiang a
new j. chem., 2002, 26, 607-613,-0001,():
-1年11月30日
mesoporous tio2 nanometer thin films were prepared on fused quartz by the dip-coating sol-gel method from a system containing a triblock copolymer as a template (or pore-forming agent), and then calcined at different temperatures. these films were characterized by x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, bet surface area and uv-visible spectrophotometry. the photocatalytic activity and photo-induced super-hydrophilicity of the films were evaluated by the photocatalytic degradation of acetone and water contact angle measurement in air, respectively. it was found that the thin films calcined at 700℃ not only show the highest photocatalytic activity, but also possess the greatest light-induced hydrophilicity and the slowest conversion rate from the hydrophilic to a hydrophobic state. the former is attributed to the fact that the films calcined at 700℃ are composed of anatase and rutile, whichis beneficial in enhancing the transfer of photo-generated electrons from the anatase to the rutile phase, reducing the electron-hole combination rate in anatase and enhancing its activity. the high light-induced hydrophilicity and slow hydrophilic to hydrophobic conversion rate are due to the synergetic effect of good photocatalytic activity, sufficient surface hydroxyl content and a degree of surface roughness. because of their high specific surface areas and mesoporous structures, the photocatalytic activity of mesoporous tio2 thin films is higher than that of conventional tio2 thin films.
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2005-03-29
余家国, jiaguo yu*, xiujian zhao
materials research bulletin 35(2000)1293-1301,-0001,():
-1年11月30日
transparent anatase tio2 nanometer thin films with photocatalytic activity were prepared via the sol-gel method on soda-lime glass, fused quartz, and soda-lime glass precoated with a sio2 layer. the resulting thin films were characterized by x-ray photoelectron spectroscopy (xps), scanning electron microscopy (sem), and x-ray diffraction (xrd). the photocatalytic activity of the various tio2 films was evaluated by the photocatalytic decolorization of aqueous methyl orange. the diffusion of sodium and calcium ions from the soda-lime glass into the nascent tio2 films was found to be detrimental to the photocatalytic activity of the resulting tio2 films. sodium and calcium diffusion into nascent tio2 films was effectively retarded by a 0.3mm sio2 interfacial layer formed on the soda-lime glass.
a., thin films, b., sol-gel chemistry, c., photoelectron spectroscopy, d., diffusion, d., catalytic properties
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2005-03-29
余家国, jiaguo yu, xiujian zhao, qingnan zhao
materials chemistry and physics 69(2001)25-29,-0001,():
-1年11月30日
transparent tio2 nanometer thin films with high photocatalytic activity were prepared on soda-lime glass substrates via the sol-gel method using the tio2 sol solution. the valency state of ti element and the chemical compositions in tio2 thin films were analyzed with x-ray photoelectron spectroscopy (xps). experimental results showed that besides ti, o and c elements there is a small amount of na and ca elements diffused from the glass substrates and besides ti(iv) there is a certain amount of ti(iii) and ti(ii) in tio2 thin film. heating temperature of 500 c may be adopted to convert tio2 gel films into tio2 (anatase) crystalline films and also the tio2 (anatase) crystalline films show the highest photocatalytic activity. it was also found that the heat treatment for a suitable time at 500 c improves remarkably the photocatalytic activity of the tio2 thin film, although for too long a time, rather deteriorates it. these results are explained on the basis of the changes in the surface structure and ti3c concentration with the heat treatment time.
sol-gel method, titanium oxide nanometer thin films, heat treatment processing, photocatalytic activity
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2005-03-29
余家国, jiaguo yu, * hua tang, bei cheng, and xiujian zhao
journal of solid state chemistry 177(2004)3368-3374,-0001,():
-1年11月30日
calcium oxalate (caox) particles exhibitingdifferent shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (psma) as a crystal modifier at room temperature. the as-obtained products were characterized with scanningelectron microscopy (sem) and x-ray diffraction (xrd). the effects of reaction conditions includingph, [ca2 ]/[c2o4 2] ratio and concentration of psma and cac2o4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. the results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (cod) crystals. lower ph is beneficial to the formation of plate-like caox crystals. especially, the monodispersed parallelogram-like caox crystals can be produced by psma as an additive at ph 2. psma may act as a good inhibitor for urolithiasis since it induces the formation of cod and reduces the particle size of caox. this research may provide new insight into the morphological control of caox particles and the prevention of urolithiasis.
calcium oxalate, precipitation reaction, morphological control, psma (, poly-(, styrene-alt-maleic acid), ), , urolithiasis, prevention
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2005-03-29
余家国, jia-guo yu, *, † huo-gen yu, † bei cheng, ‡ xiu-jian zhao, ‡ jimmy c. yu, § and wing-kei ho§
j. phys. chem. b 2003, 107, 13871-13879,-0001,():
-1年11月30日
f f, n, and si elements. the f and n came from the precursor solution, and the amount of f decreased with increasing calcination temperature. two sources of si were identified. one was from the sif6 2-ions, which were formed by a reaction between the treatment solution and quartz substrate. the other was attributed to the diffusion of si from the surface of quartz substrate into tio2 thin film at 700℃ or higher calcination temperatures. with increasing calcination temperature, the photocatalytic activity of the tio2 thin films gradually increased due to the improvement of crystallization of the anatase tio2 thin films. at 700℃, the tio2 thin film showed the highest photocatalytic activity due to the increasing amount of sio2 as an adsorbent center and better crystallization of tio2 in the composite thin film. moreover, the sio2/tio2 composite thin film showed the lowest pl intensity due to a decrease in the recombination rate of photogenerated electrons and holes under uv light irradiation, which further confirms the film with the highest photocatalytic activity at 700℃. when the calcination temperature is higher than 700℃, the decrease in photocatalytic activity is due to the formation of rutile and the sintering and growth of tio2 crystallites resulting in the decrease of surface area.
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2005-03-29
余家国, jiaguo yu a, *, minghua zhou a, b, bei cheng a, huogen yu a, xiujian zhao a
journal of molecular catalysis a: chemical 227(2004)75-80,-0001,():
-1年11月30日
mesoporous titanium dioxide nanocrystalline powders were synthesized by ultrasonic-induced hydrolysis reaction of tetrabutyl titanate (ti(oc4h9)4) in pure water without using any templates or surfactants. the as-prepared samples were characterized with x-ray diffraction (xrd) and n2 adsorption-desorption measurements. the photocatalytic activity of the samples was evaluated using the probe reaction: the photocatalytic oxidation of mixture of formaldehyde and acetone at room temperature. it was found that the as-prepared products by the ultrasonic method were composed of anatase and brooktie phases. the photocatalytic activity of the samples prepared by ultrasonic method is higher than that of commercial degussa p25 and the samples prepared by conventional hydrolysis method.
tio2, mesoporous, nanocrystalline, ultrasonic-induced hydrolysis, photocatalytic degradation, formaldehyde, acetone
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2005-03-29
余家国, jiaguo yu, a, b jimmy c. yu, b, * mitch k.-p. leung, b wingkei ho, b bei cheng, a xiujian zhao, a and jincai zhao c
journal of catalysis 217(2003)69-78,-0001,():
-1年11月30日
bimodal mesoporous titania powders with high photocatalytic activity were prepared by hydrolysis of titanium tetraisopropoxide in the presence of hno3 or nh4oh under ultrasonic irradiation. the powders were characterized by x-ray diffraction (xrd), scanning electron microscopy (sem), bet surface areas, and x-ray photoelectron spectroscopy (xps). photocatalytic activity was evaluated by the photocatalytic oxidation of acetone in air. the effects of catalysts added during hydrolysis on the microstructure and photocatalytic activity of the tio2 powders were investigated. the results showed that hno3 enhanced the growth of brookite, while nh4oh not only retarded phase transformation of the tio2 powders from amorphous to anatase and anatase to rutile but also suppressed the growth of brookite. all tio2 powders calcined from 400 to 600℃ showed bimodal pore-size distributions in the mesoporous region: one was intraaggregated pores with maximum pore diameters of ca. 4-9nm and the other interaggregated ones with maximum pore diameters of ca. 3550nm. at 700℃, the pore-size distributions of all samples exhibited monomodal distribution of the interaggregated pores due to the collapse of the intraaggregated pores. the photocatalytic activity of the tio2 powders prepared by this method and calcined at 400℃ exceeded that of degussa p-25 when the molar ratio of hno3 or nh4oh to h2o was less than 0.05.
mesoporous titania, titanium isopropoxide, hydrolysis, hno3, nh4oh, microstructures, photocatalytic activity
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