Activity enhancement of platinum oxygen-reduction electrocatalysts using ion-beam induced defects

Kimata, Tetsuya*; Kakitani, Kenta*; Yamamoto, Shunya*; Shimoyama, Iwao; Matsumura, Daiju; Iwase, Akihiro*; Mao, W.*; Kobayashi, Tomohiro*; Yamaki, Tetsuya*; Terai, Takayuki*

Physical Review Materials (Internet), 6(3), p.035801_1 - 035801_7, 2022/03

https://doi.org/10.1103/PhysRevMaterials.6.035801

Platinum nanoparticles on the glassy carbon surface irradiated with argon ions

Kimata, Tetsuya*; Kato, Sho*; Yamaki, Tetsuya; Yamamoto, Shunya; Kobayashi, Tomohiro*; Terai, Takayuki*

Surface & Coatings Technology, 306(Part A), p.123 - 126, 2016/11

https://doi.org/10.1016/j.surfcoat.2016.05.042

Platinum (Pt) nanoparticle catalysts with oxygen reduction reaction (ORR) activity are required for practical applications of polymer electrolyte fuel cells. We prepared Pt nanoparticles on an Ar-irradiated glassy carbon (GC) surface by a radio-frequency magnetron sputtering method to investigate the influence of the ion-induced lattice defects in GC on the ORR activity of the deposited Pt nanoparticles. Interestingly, the Pt nanoparticles on the irradiated surface exhibited ca. 2.5 times higher specific activity than those on the non-irradiated one. X-ray photoelectron spectroscopy suggested the interfacial Pt-C interaction occurring between the irradiated GC and Pt nanoparticles, which should be a reason for improvement of the ORR activity.

Preparation of tungsten carbide nanoparticles by ion implantation and electrochemical etching

Kato, Sho; Yamaki, Tetsuya; Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Kobayashi, Tomohiro*; Suzuki, Akihiro*; Terai, Takayuki*

Nuclear Instruments and Methods in Physics Research B, 314, p.149 - 152, 2013/11

https://doi.org/10.1016/j.nimb.2013.05.052

We implanted 100 keV W in unpolished GC substrates at nominal fluences up to ions/cm. The implanted samples were electrochemically anodized in a NaOH aqueous solution to etch the surface layer. The analyses were performed by X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), and transmission electron microscopy (TEM). XPS W 4f spectra indicated the formation of carbides as reported previously. The electrochemical etching clearly increased the W concentration on the surface. According to the RBS results, half of the implanted W atoms were retained in the substrate, while the rest should escape to the etching solution. The cross-sectional TEM image revealed a uniform distribution of WC particles with a diameter of less than 10 nm just near the surface region.

Microfabrication on Teflon surface by MeV-proton-microbeam and keV-nitrogen-ion-beam irradiation

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kobayashi, Tomohiro*; Kamiya, Tomihiro

Nuclear Instruments and Methods in Physics Research B, 307, p.610 - 613, 2013/07

https://doi.org/10.1016/j.nimb.2013.01.017

A New microfabrication technique of fluoropolymer was developed, using ion beam

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kobayashi, Tomohiro*; Kamiya, Tomihiro

Hoshasen To Sangyo, (134), p.37 - 40, 2013/06

no abstracts in English

Nanoparticle formation by tungsten ion implantation in glassy carbon

Kato, Sho; Yamaki, Tetsuya; Yamamoto, Shunya; Hakoda, Teruyuki; Kawaguchi, Kazuhiro; Kobayashi, Tomohiro*; Suzuki, Akihiro*; Terai, Takayuki*

Transactions of the Materials Research Society of Japan, 38(1), p.81 - 84, 2013/03

https://doi.org/10.14723/tmrsj.38.81

Nanoparticles were formed by 100 keV tungsten-ion implantation in unpolished glassy carbon substrates at nominal fluences of - ions/cm. The implanted samples were analyzed by Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, hydrodynamic voltammetry using a rotating disk electrode, and field emission scanning electron microscopy. A significant sputtering effect changed the depth profile during the course of irradiation and limited the amount of tungsten retainable in the substrate in agreement with our calculated distributions. The nanoparticles were composed of tungsten carbide and dispersed uniformly with diameters of around 10 nm.

Morphological change of PTFE by ion micro beam irradiation

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Kobayashi, Tomohiro*

Transactions of the Materials Research Society of Japan, 37(2), p.219 - 222, 2012/06

https://doi.org/10.14723/tmrsj.37.219

Oxygen reduction activity of N-doped carbon based films prepared by pulsed laser deposition

Hakoda, Teruyuki; Yamamoto, Shunya; Kawaguchi, Kazuhiro; Yamaki, Tetsuya; Kobayashi, Tomohiro*; Yoshikawa, Masahito

no journal, , 

no abstracts in English

Morphological change of fluoropolymer surface by ion micro beam irradiation

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Kobayashi, Tomohiro*

no journal, , 

no abstracts in English

Three dimentional microfabrication of fluoropolymer surface by proton beam writing

Kitamura, Akane; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Kobayashi, Tomohiro*

no journal, , 

no abstracts in English