Co-reporter:Yoshifumi Ishikawa;Maiki Takeda;Susumu Tsukimoto;Koji S. Nakayama
Advanced Materials 2016 Volume 28( Issue 7) pp:1467-1471
Publication Date(Web):
DOI:10.1002/adma.201504101
Co-reporter:Yoshifumi Ishikawa, Susumu Tsukimoto, Koji S. Nakayama, and Naoki Asao
Nano Letters 2015 Volume 15(Issue 5) pp:2980-2984
Publication Date(Web):April 15, 2015
DOI:10.1021/nl504820c
Ultrafine sodium titanate nanowires are produced from TiAl alloy precursors via a nonthermal process where Al leaching and Ti oxidation occur simultaneously in an alkaline medium. The obtained nanowires demonstrate a layered crystal structure with a diameter of a few nanometers and exhibit remarkable Sr ion-exchange properties.
Co-reporter:Naoki Asao
The Chemical Record 2015 Volume 15( Issue 5) pp:964-978
Publication Date(Web):
DOI:10.1002/tcr.201500204
Abstract
Two types of nanomaterials with different morphologies are described in this article: nanoporous metals and titanate nanowires. Both materials are fabricated by a dealloying method. In the former case, the catalytic properties of nanoporous gold and palladium are exemplified by many chemical transformations. The reactions proceed without any support, stabilizer, or ligands. The catalyst can be easily recovered by a simple separation process and reused many times without significant loss of catalytic activity. In the latter case, the dealloying of Ti–Al alloy is described as a new fabrication method for producing ultrafine titanate nanowires. This method does not require high-temperature conditions, which is advantageous for the construction of fine structures. The key to this process is achieving a fine dispersion of intermetallic TiAl3 nanocrystals in the Al matrix in the mother alloy. The resulting nanowires exhibit remarkable Sr2+ ion-exchange properties.
Co-reporter:Yogesh S. Wagh and Naoki Asao
The Journal of Organic Chemistry 2015 Volume 80(Issue 2) pp:847-851
Publication Date(Web):December 18, 2014
DOI:10.1021/jo502313d
A facile, highly chemo- and stereoselective transfer semihydrogenation of alkynes to Z-olefins has been achieved by use of unsupported nanoporous gold (AuNPore) as a heterogeneous catalyst together with formic acid as a hydrogen donor. A variety of terminal/internal and aromatic/aliphatic alkynes were reduced to the corresponding alkenes in high chemical yields with good functional-group tolerance. The catalyst is robust enough to be reused without leaching.
Co-reporter:Salprima Yudha S, Indra Kusuma, Naoki Asao
Tetrahedron 2015 Volume 71(Issue 37) pp:6459-6462
Publication Date(Web):16 September 2015
DOI:10.1016/j.tet.2015.05.094
A facile preparation of nitrones has been achieved by use of unsupported nanoporous gold (AuNPore) as a heterogeneous catalyst through aerobic oxidation of N,N-disubstituted hydroxylamines with molecular oxygen as an oxidizing agent under mild conditions. A variety of amines were oxidized to the corresponding nitrones in high chemical yields. The catalyst is robust enough to be reused without leaching.
Co-reporter:Patrick Han, Kazuto Akagi, Filippo Federici Canova, Ryota Shimizu, Hiroyuki Oguchi, Susumu Shiraki, Paul S. Weiss, Naoki Asao, and Taro Hitosugi
ACS Nano 2015 Volume 9(Issue 12) pp:12035
Publication Date(Web):November 20, 2015
DOI:10.1021/acsnano.5b04879
We use self-assembly to fabricate and to connect precise graphene nanoribbons end to end. Combining scanning tunneling microscopy, Raman spectroscopy, and density functional theory, we characterize the chemical and electronic aspects of the interconnections between ribbons. We demonstrate how the substrate effects of our self-assembly can be exploited to fabricate graphene structures connected to desired electrodes.Keywords: bottom-up fabrication; graphene interconnections; graphene nanoribbons; scanning tunneling microscopy; surface-assisted molecular assembly;
Co-reporter:Patrick Han, Kazuto Akagi, Filippo Federici Canova, Hirotaka Mutoh, Susumu Shiraki, Katsuya Iwaya, Paul S. Weiss, Naoki Asao, and Taro Hitosugi
ACS Nano 2015 Volume 9(Issue 4) pp:3404
Publication Date(Web):April 28, 2015
DOI:10.1021/acsnano.5b01687
Co-reporter:Ming Zhao, Katsuhiro Abe, Shin-ichi Yamaura, Yoshinori Yamamoto, and Naoki Asao
Chemistry of Materials 2014 Volume 26(Issue 2) pp:1056
Publication Date(Web):December 29, 2013
DOI:10.1021/cm403185h
We report the chemical fabrication of metallic glass nanoparticles (MG-NPs). Using commercially available Pd, Ni, and P precursors, size-controlled amorphous Pd–Ni–P NPs were obtained by a one-pot solvothermal synthesis procedure. Differential scanning calorimetry identified typical MG properties of the unsupported Pd–Ni–P NPs with a wide supercooling region of 55 K (602–657 K). Notably, the supported MG-NPs showed remarkable catalytic properties in methanol electro-oxidation in an alkaline medium. After 400 cyclic voltammetry cycles, the loss of current density was only 3.5% when Pd–Ni–P NPs on Vulcan XC-72 were used as a catalyst. This catalytic durability is outstanding compared to those of many other Pd- or Pt-based nanocatalysts, including the recently reported precious Pt–Pd nanomaterials. These results indicate the potential use of Pd-based MG-NPs as fuel cell catalysts.
Co-reporter:Patrick Han, Kazuto Akagi, Filippo Federici Canova, Hirotaka Mutoh, Susumu Shiraki, Katsuya Iwaya, Paul S. Weiss, Naoki Asao, and Taro Hitosugi
ACS Nano 2014 Volume 8(Issue 9) pp:9181
Publication Date(Web):August 27, 2014
DOI:10.1021/nn5028642
We produce precise chiral-edge graphene nanoribbons on Cu{111} using self-assembly and surface-directed chemical reactions. We show that, using specific properties of the substrate, we can change the edge conformation of the nanoribbons, segregate their adsorption chiralities, and restrict their growth directions at low surface coverage. By elucidating the molecular-assembly mechanism, we demonstrate that our method constitutes an alternative bottom-up strategy toward synthesizing defect-free zigzag-edge graphene nanoribbons.Keywords: bottom-up fabrication; graphene nanoribbons; scanning tunneling microscopy; surface-assisted molecular assembly;
Co-reporter:Yoshifumi Ishikawa, Yoshinori Yamamoto and Naoki Asao
Catalysis Science & Technology 2013 vol. 3(Issue 11) pp:2902-2905
Publication Date(Web):21 May 2013
DOI:10.1039/C3CY00242J
The hydrosilylation of acetylenic compounds proceeded smoothly in the presence of a reusable nanoporous gold catalyst under mild conditions and the β-(E)-cis-addition products were obtained in good to high yields regio- and stereoselectively.
Co-reporter:Naoki Asao, Naoya Hatakeyama, Menggenbateer, Taketoshi Minato, Eisuke Ito, Masahiko Hara, Yousoo Kim, Yoshinori Yamamoto, Mingwei Chen, Wei Zhang and Akihisa Inoue
Chemical Communications 2012 vol. 48(Issue 38) pp:4540-4542
Publication Date(Web):23 Jan 2012
DOI:10.1039/C2CC17245C
Aerobic oxidation of alcohols in the liquid phase proceeded smoothly in the presence of nanoporous gold catalyst. The catalyst is reusable multiple times without leaching and loss of the catalytic activity. The reaction was applied successfully to a flow system. Adsorptions of O2 and 1-phenylethanol into the AuNPore were confirmed by TDS analysis.
Co-reporter:Shinya Tanaka, Tetsuro Kaneko, Naoki Asao, Yoshinori Yamamoto, Mingwei Chen, Wei Zhang and Akihisa Inoue
Chemical Communications 2011 vol. 47(Issue 21) pp:5985-5987
Publication Date(Web):19 Apr 2011
DOI:10.1039/C1CC10710K
Nanoporous metallic glass Pd, which was fabricated by dealloying of a glassy metallic alloy Pd30Ni50P20, exhibited a remarkable catalytic activity for the Suzuki-coupling reaction between iodoarenes and arylboronic acids under mild conditions. Moreover, the catalyst can be reused several times without a significant loss of catalytic activity.
Co-reporter:Tetsuro Kaneko;Shinya Tanaka;Yoshinori Yamamoto;Mingwei Chen;Wei Zhang;Akihisa Inoue
Advanced Synthesis & Catalysis 2011 Volume 353( Issue 16) pp:2927-2932
Publication Date(Web):
DOI:10.1002/adsc.201100358
Abstract
Nanoporous metallic glass palladium (PdNPore), which was fabricated by de-alloying of a glassy metallic alloy Pd30Ni50P20, exhibited a remarkable catalytic activity for the Heck reaction of versatile aryl iodides and aryl bromides. Moreover, the PdNPore can be reused several times without a significant loss of catalytic activity, and the PdNPore has ahigher resistance to leaching than palladium black and palladium on carbon.
Co-reporter:Dr. Naoki Asao;Yoshifumi Ishikawa;Naoya Hatakeyama;Dr. Menggenbateer;Dr. Yoshinori Yamamoto;Dr. Mingwei Chen;Dr. Wei Zhang;Dr. Akihisa Inoue
Angewandte Chemie 2010 Volume 122( Issue 52) pp:10291-10293
Publication Date(Web):
DOI:10.1002/ange.201005138
Co-reporter:Dr. Naoki Asao;Yoshifumi Ishikawa;Naoya Hatakeyama;Dr. Menggenbateer;Dr. Yoshinori Yamamoto;Dr. Mingwei Chen;Dr. Wei Zhang;Dr. Akihisa Inoue
Angewandte Chemie International Edition 2010 Volume 49( Issue 52) pp:10093-10095
Publication Date(Web):
DOI:10.1002/anie.201005138
Co-reporter:Yoshifumi Ishikawa, Yoshinori Yamamoto and Naoki Asao
Catalysis Science & Technology (2011-Present) 2013 - vol. 3(Issue 11) pp:NaN2905-2905
Publication Date(Web):2013/05/21
DOI:10.1039/C3CY00242J
The hydrosilylation of acetylenic compounds proceeded smoothly in the presence of a reusable nanoporous gold catalyst under mild conditions and the β-(E)-cis-addition products were obtained in good to high yields regio- and stereoselectively.
Co-reporter:Shinya Tanaka, Tetsuro Kaneko, Naoki Asao, Yoshinori Yamamoto, Mingwei Chen, Wei Zhang and Akihisa Inoue
Chemical Communications 2011 - vol. 47(Issue 21) pp:NaN5987-5987
Publication Date(Web):2011/04/19
DOI:10.1039/C1CC10710K
Nanoporous metallic glass Pd, which was fabricated by dealloying of a glassy metallic alloy Pd30Ni50P20, exhibited a remarkable catalytic activity for the Suzuki-coupling reaction between iodoarenes and arylboronic acids under mild conditions. Moreover, the catalyst can be reused several times without a significant loss of catalytic activity.
Co-reporter:Naoki Asao, Naoya Hatakeyama, Menggenbateer, Taketoshi Minato, Eisuke Ito, Masahiko Hara, Yousoo Kim, Yoshinori Yamamoto, Mingwei Chen, Wei Zhang and Akihisa Inoue
Chemical Communications 2012 - vol. 48(Issue 38) pp:NaN4542-4542
Publication Date(Web):2012/01/23
DOI:10.1039/C2CC17245C
Aerobic oxidation of alcohols in the liquid phase proceeded smoothly in the presence of nanoporous gold catalyst. The catalyst is reusable multiple times without leaching and loss of the catalytic activity. The reaction was applied successfully to a flow system. Adsorptions of O2 and 1-phenylethanol into the AuNPore were confirmed by TDS analysis.