■■■Research / 研究■■■
A BRIEF SUMMARY OF DR. SHU YIN’ S RESEARCH ACHIEVEMENT:
Dr. Shu YIN, He received a B. S. degree in inorganic chemical engineering from the Dalian University of Technology in 1987. He received a M. S. degree in chemical metallurgy from the Institute of Chemical Metallurgy (ICM, latterly Institute of Process and Engineering, IPE), Chinese Academy of Science in 1990, then worked as a research associate for 2 years at ICM. He came to Japan and worked as a research fellow in the Hydrothermal Chemistry Research Laboratory (Prof. N.Yamasaki’s Group), Kochi University in 1992, then became a research assistant at the Institute for Chemical Reaction Science (ICRS, Prof.T.Sato’s group), Tohoku University during 1995-1997. He received a Ph.D. degree in applied chemistry from Tohoku University (research period shortened) in 1999. He has been a full-time research assistant at the ICRS in 1999, then a lecture at the Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University in 2005, and then a full-time associate professor in 2005. He is also an affiliate professor of three Chinese Universities / Institute(Lanzhou University; Dalian University of Technology; Guangxi Research Institute of Chemical Industry). His research papers were cited more than 4400 times and showed a citation h-index = 39. He has also participated in the organization of some international conferences and acted as session chair in more than 20 international conferences. Until now, he was invited to act as independent reviewer and referee for more than 40 academic journals. His research interests include morphological control of nanostructured materials, photocatalytic materials, UV-shielding materials, hydrothermal / solvothermal process, soft chemical synthesis. He has authored more than 320 original research papers(IF>4: more than 60papers), contributed 21 book chapters/ review papers and 20 patents. He has co-authored nearly 170 international conference presentations and presented more than 39 invited talks since 2004.
(1) Solvothermal Synthesis of Zirconia Based Nano-particles and its Low-temperature Sintering Properties.
Zirconia based nano-particles such as Ce / Y / Mg / Ca doped ZrO2 particles with / without alumina composite were successfully prepared by solvothermal process. The well-crystallized fine products showed excellent low-temperature properties. Above 98% density could be realized by low-temperature sintering at 1100oC, which is about 350oC lower than that of commercial powders. By using the prepared fine particles, sintered body showed much higher mechanical properties and thermal stability.
Based on the related achievement, Dr.S.Yin won the 40th Harada award.
(2) Solvothermal Synthesis of Fibrous Titania Photocatalyst.
The photocatalytic destruction of NO is of great significance from a practical application viewpoint because NO is one of the most common pollutants found in exhaust emissions from automobiles. In 2004, a Japanese industrial standard (JIS standard) for photocatalytic deNOx reaction was established. Titania is the most effective photocatalyst. In comparison with nanoparticles, two-dimensional fibrous particles has many advantages such as easy handling, high mechanical strength when using as additives, and high performance related to their special morphologies. We successfully prepared fibrous titania photocatalyst consisted of well-crystallized nanoparticles and comparatively high specific surface area, which are important factors in the photocatalytic application, under solvothermal reactions. The application research on wall-paper with photocatalytic ability was carried out as collaboration research with Otsuka Chemical Co.Ltd, and the productions of wall-paper consisted of fibrous titania were commercialized.
The related papers were published in J. Mater. Chem., Ind. Eng. Chem. Res. etc. The total citation related to this research is more than 140 times.
(3) Selective Synthesis of Nitrogen Titania with Various Phase Compositions and their deNOx application
Although many kinds of semiconductor materials could be used as photocatalysts, titania remains as the most effective one and can be applied to the photocatalytic decomposition of many pollutants such as nitrogen monoxide and volatile organic compounds (VOC). On the other hand, titania can only be encouraged by UV light because of its large band gap value of ca. 3 eV. In order to utilize the solar energy effectively, it is necessary to develop a visible light reactive photocatalyst. Nitrogen or other anion doping is thought to be the most effective way to narrow the band gap of titania. Normally, nitrogen doped titania was synthesized at such high temperatures as 550-850oC, and some processes also used some expensive precursors such as TiN, TiC, and TiS2, etc. In addition, high temperature treatment process leads to the increase of crystallinity, but great decrement of specific surface area and anion doped amount, and finally leads to the decrement of photocatalytic activity.
In this research, we firstly synthesized the nitrogen doped titania by the environmental friendly solvothermal processes successfully. Nitrogen-doped titania particles consisting of single phases of anatase, rutile and brookite with controllable particle size and various morphologies were selectively synthesized.
The samples prepared by solvothermal reaction in methanol / ethanol solutions showed better visible-light absorption, photocatalytic deNOx activity and thermal stability than those obtained by hydrothermal / conventional high temperature processes. Metallic ions loading led to the great improvement of the photocatalytic activity and quantum yield. It was confirmed that NOx could be continuously removed successfully, not only under UV light irradiation but also under some visible light sources such as solar light and even long-wavelength monochrome LED light (red LED: l > 627 nm; green LED: l > 530 nm; blue LED: l > 445 nm, with light intensity of 2 mW).
The related research papers were published in J. Mater. Chem., J. Phys. Chem. C, J. Photochem. Photobiol.A-Chem. J. Eur. Ceram. Soc. etc. and 4 invited talks were contributed on related international conferences. The total citation related to this research is more than 120 times.
(4) Mechanochemical Synthesis of Visible-light Induced Anion doped Photocatalysts
Environmental friendly low-temperature mechanochemical doping process was successfully developed. Not only nitrogen, but also some other anions such as sulfur or carbon could be doped or co-doped into photocatalyst under such low treatment temperature as 60oC. By selecting various anion source reagents and treatment atmospheres in the mechanochemical doping process, many kinds of visible-light-active anion doped photocatalyst such as TiO2-xNy, TiO2-xCy, TiO2-xSy,TiO2-xNyCz, SrTiO3-xNy, SrTiO3-xFy, SrTiO3-xNyFz, LaxSr1-xTiO3-yNz, ZnO1-xNy, were successfully prepared. It was found that the mechanochemical method is an effective way for nonmetallic element doping in oxides and other inorganic materials. Combined with oxygen plasma treatment, photocatalyst thin films was successfully prepared on some thermal-unstable substrates such as wood, paper and plastic substrate
T The related research papers were published in J. Mater. Chem., Appl. Catal. B-Environ., Environ. Sci. Tecnnol. J. Am. Ceram. Soc., J. Photochem. Photobiol. A-Chem. J. Eur. Ceram. Soc. etc. and 2 invited talks were contributed on related international conferences. The total citation related to this research is more than250 times.
(5) Morphological Control of Rare Earth Oxides by Solvothermal Process.
Eu doped Y2O3 and some kinds of other rare earth oxides nanoparticles such as Er2O3, Nd2O3, Ho2O3, Lu2O3, and Dy2O3 with spherical and fiber morphologies were successfully prepared by a simple co-precipitation-solvothermal treatment-calcination process. The aspect ratio of the rare earth oxide is precisely controllable by using various solvents with different dielectric constant. The powders prepared using ethylene glycol consisted of well dispersed near-spherical nanoparticles and showed high photoluminescence intensity. The related research papers were published in J. Lumin. and J. Mater. Sci. etc.
(6) Solution Synthesis of Ceria Based UV-Shielding Materials.
Ceria is a potential UV shielding materials because of its low photocatalytic activity and high UV shielding ability and transparency. However, the high oxide catalytic activity limited its applications on cosmetic research. In the present research, nanoparticles of Ce1-xMxO2-x (x = 0–0.561, M= Ca or Zn) solid solutions were successfully prepared via soft solution chemical routes below 100oC. It was found that doping ZnO and CaO with CeO2 resulted in decreasing the oxidation catalytic activity of CeO2 without loss of UV shielding ability and transparency in the visible light region. These results make it possible to be utilized as inorganic cosmetics materials. Usually, it is accepted that there is some difficulties to prepare plate-like particles with the crystalline phase of cubic. We suggested a novel synthesis process, i.e. at first synthesis of a plate like precursor by solution process, then transformed the plate-like structure to cubic phase particles. Fortunately, we have successfully plate-like cerium carbonate single crystal, and 1 patent will be applied.
The application research on cosmetics containing ca-doped ceria nanoparticles was carried out as a collaboration with KOSE Co.Ltd., and the productions of lip-stick consisted of ca-doped ceria nanoparticles was carried out as a collaboration with KOSE Co.Ltd., and the productions of were commercialized.
(7) Solution Synthesis of Oxide Thin Films with Superstructure and Novel Functions.
Controlled growth of nanocrystallines has stimulated wide interesting in material research. Generally, zinc oxides with various morphologies are prepared by solid-state thermal sublimation process or other high temperature processes. It is generally accepted that the formation of zinc oxide superstructures in liquid media is more difficult than that from solid-state thermal sublimation process, because the crystalline growth in solution is mainly related to the comparatively low diffusion rate of ions and precipitation rate in liquid media, resulting in difficulty in rapid epitaxial growth. In the present research, novel superstructures of zinc oxide films, i.e., nanorods, nanoscrews, and nanodisks structures were successfully prepared by treatment of “low-concentration precursor solution” with desired time aging. It was firstly found that zinc oxide films with various superstructure showed quite different hydrophilicity (contact angle for water drops). It was found that the ZnO film with nano-rod structure showed a contact angle of 165o and possessed superhydrophobicity. On the other hand, the ZnO film with nano-screw structure possessed superhydrophilicity, i.e., super wetting properties for water drops. Some other superstructures such as nano-disk, nano-flower and nano-carpet consisted of nanoscrew superstructure were also successfully prepared. The application researches on cosmetics are undergoing.
The related research papers were published in J. Mater. Chem., etc. and 5 invited talks were contributed on related international conferences. This research also won the “excellent academic photograph award” from the Ceramic Society of Japan,
（装置・撮影条件）SEM（Hitachi S─4100L），TEM（JEOL JEM─2000EX），加速電圧15kV，200kV
（出品者所属・氏名）（東北大学）殷 澍・唐 清・佐藤次雄
＜選評 by Ceramic Society of Jpn＞
(8) Microwave Assisted Solvothermal Synthesis of Functional Inorganic Materials.
Instead of conventional hydrothermal / solvothermal process, we successfully prepared monoclinic phase of nitrogen doped titania by microwave assisted solvothermal reactions within such short reaction time as 5 min. In addition, a new compound, tin(II) titanium(IV) oxide hydroxide fluoride, Sn1.24Ti1.94O3.66(OH)1.50F1.42, with the pyrochlore–type structure, was firstly successfully prepared by the microwave assisted solvothermal synthesis. The Tin(II) compound is thought to be a candidate of a replacement material of non-lead piezoelectric ceramics material. Usually, Sn(II) compound such as titanate cannot be obtained via conventional ceramic processing routes, i.e., solid state reaction, because of the disproportionation reaction of Sn(II) to Sn and Sn(IV) at high temperatures. Fortunately, we have firstly succeeded in synthesizing the new pyrochlore-type compound Sn1.24Ti1.94O3.66(OH)1.50F1.42, as a nanosized single phase (100 nm) by microwave assisted solvothermal reaction.
The related research papers were published in Chem. Mater. etc. and 2patents were applied.