Radiolytic synthesis of carbon-supported PtRu nanoparticles using high-energy electron beam: effect of pH control on the PtRu mixing state and the methanol oxidation activity

  • Yuji Ohkubo
  • Satoru Kageyama
  • Satoshi Seino
  • Takashi Nakagawa
  • Junichiro Kugai
  • Hiroaki Nitani
  • Koji Ueno
  • Takao A. Yamamoto
Research Paper

Abstract

Electrode catalysts composed of carbon-supported PtRu nanoparticles (PtRu/C) for use as a direct methanol fuel cell anode were synthesized by the reduction of precursor ions in an aqueous solution via irradiation with a high-energy electron beam. The effect of pH control in the precursor solution on the PtRu mixing state and the methanol oxidation activity was studied in order to enhance the catalytic activity for methanol oxidation. The PtRu/C structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray fluorescence spectrometry, and X-ray diffraction and X-ray absorption fine structure techniques. The methanol oxidation activity was evaluated by linear sweep voltammetry. The initial pH of the precursor solution has little influence on the average grain size for the metal particles (approximately 3.5 nm) on the carbon particle supports, but the dispersibility of the metal particles, PtRu mixing state, and methanol oxidation activity differed. The maintenance of a low pH in the precursor solution gave the best dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles, whereas, a high pH gave the best PtRu mixing state and the highest oxidation current although a low dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles was obtained. The PtRu mixing state strongly correlated with the methanol oxidation current. In addition, a high pH was more effective for PtRu mixing when using an electron beam irradiation reduction method, because the complexation reaction of the chelating agents was improved, which resulted in an enhancement of the catalytic activity for methanol oxidation.

Keywords

Radiolytic synthesis PtRu pH control Direct methanol fuel cell Methanol oxidation activity 

Notes

Acknowledgments

This study was mainly supported by Grant-in-Aid for Scientific Research A (Grant-in-Aid No. 22241023) and Grant-in-Aid for JSPS Fellows. The authors thank the staff of the Japan Electron Beam Irradiation Service, Ltd., for their assistance with the electron beam irradiation experiments. The authors are also thankful for partial support from the Ministry of Economy, Trade and Industry (R&D Project for Regional Innovation No. 22U5009).

References

  1. Belloni J (2006) Nucleation, growth and properties of nanoclusters studied by radiation chemistry: application to catalysis. Catal Today 113:141–156. doi: 10.1016/j.cattod.2005.11.082 CrossRefGoogle Scholar
  2. Hamnett A, Kennedy BJ (1998) Bimetallic carbon supported anodes for the direct methanol–air fuel cell. Electrochem Acta 33:1613–1618. doi: 10.1016/0013-4686(88)80233-0 CrossRefGoogle Scholar
  3. Kageyama S, Seino S, Nakagawa T, Nitani H, Ueno K, Daimon H, Yamamoto TA (2011) Formation of PtRu alloy nanoparticle catalyst by radiolytic process assisted by addition of dl-tartaric acid and its enhanced methanol oxidation activity. J Nanopart Res 13:5275–5287. doi: 10.1007/s11051-011-0513-x CrossRefGoogle Scholar
  4. Kageyama S, Murakami A, Ichikawa S, Seino S, Nakagawa T, Daimon H, Ohkubo Y, Kugai J, Yamamoto TA (2012) Enhanced electrochemical stability of PtRuAu/C catalyst synthesized by radiolytic process. J Mater Res 27:1037–1045. doi: 10.1557/jmr.2012.65 CrossRefGoogle Scholar
  5. Kageyama S, Sugano Y, Hamaguchi Y, Kugai J, Ohkubo Y, Seino S, Nakagawa T, Ichikawa S, Yamamoto TA (2013) Mater Res Bullet 48:1347–1351. doi: 10.1016/j.materresbull.2012.11.028 Google Scholar
  6. Nakagawa T, Nitani H, Tanabe S, Okitsu K, Seino S, Mizukoshi Y, Yamamoto TA (2005) Structure analysis of sonochemically prepared Au/Pd nanoparticles dispersed in porous silica matrix. Ultrason Sonochem 12:249–254. doi: 10.1016/j.ultsonch.2004.02.002 CrossRefGoogle Scholar
  7. Newville M, Ravel B, Haskel D, Rehr JJ, Stern EA, Yacoby Y (1995) Analysis of multiple-scattering XAFS data using theoretical standards. Phys B Phys Condens Matter 208–209:154–156. doi: 10.1016/0921-4526(94)00655-F CrossRefGoogle Scholar
  8. Nitani H, Yuya M, Ono T, Nakagawa T, Seino S, Okitsu K, Mizukoshi Y, Emura S, Yamamoto TA (2006) Sonochemically synthesized core-shell structured Au–Pd nanoparticles supported on γ-Fe2O3 particles. J Nanopart Res 8:951–958. doi: 10.1007/s11051-005-9048-3 CrossRefGoogle Scholar
  9. Nitani H, Nakagawa T, Daimon H, Kurobe Y, Ono T, Honda Y, Koizumi A, Seino S, Yamamoto TA (2007) Methanol oxidation catalysis and structure of PtRu bimetallic nanoparticles. Appl Catal A Gen 326:194–201. doi: 10.1016/j.apcata.2007.04.018 CrossRefGoogle Scholar
  10. Ohkubo Y, Shibata M, Kageyama S, Seino S, Nakagawa T, Kugai J, Yamamoto TA (2011) Radiation induced synthesis of Au–Pd nanoparticles of random alloy structure supported on carbon particles using the high energy electron beam. Mater Lett 65:2165–2167. doi: 10.1016/j.matlet.2011.04.023 CrossRefGoogle Scholar
  11. Ravel B, Newville M (2005) ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J Synchrotron Radiat 12:537–541. doi: 10.1107/S0909049505012719 CrossRefGoogle Scholar
  12. Rehr JJ, Albers RC (2000) Theoretical approaches to X-ray absorption fine structure. Rev Mod Phys 72:621–654. doi: 10.1103/RevModPhys.72.621 CrossRefGoogle Scholar
  13. Schnetder D, Esch U (1944) Das System Kupfer-Platin. Zeitschrift für Elektrochemie und Angewandte Physikalische Chemie 50:290–301. doi: 10.1002/bbpc.19440501109 Google Scholar
  14. Seino S, Kinoshita T, Nakagawa T, Kojima T, Taniguci R, Okuda S, Yamamoto TA (2008) Radiation induced synthesis of gold/iron-oxide composite nanoparticles using high energy electron beam. J Nanopart Res 10:1071–1076. doi: 10.1007/s11051-007-9334-3 CrossRefGoogle Scholar
  15. Vegard L (1921) Die Konstitution der Mischkristalle und die Raumfüllung der Atome. Zeitschrift für Physik 5:17–26. doi: 10.1007/BF01327675 CrossRefGoogle Scholar
  16. Watanabe M, Motoo S (1975) Electrocatalysis by ad-atoms. Part II. Enhancement of oxidation of methanol on platinum by ruthenium ad-atoms. J Electroanal Chem 60:267–273CrossRefGoogle Scholar
  17. Yamamoto TA, Nakagawa T, Seino S, Nitani H (2010) Bimetallic nanoparticles of PtM(M = Au, Cu, Ni) supported on iron oxide: radiolytic synthesis and CO oxidation catalysis. Appl Catal A Gen 387:195–202. doi: 10.1016/j.apcata.2010.08.020 CrossRefGoogle Scholar
  18. Yamamoto TA, Kageyama S, Seino S, Nitani H, Nakagawa T, Horioka R, Honda Y, Ueno K, Daimon H (2011) Methanol oxidation catalysis and substructure of PtRu/C bimetallic nanoparticles synthesized by a radiolytic process. Appl Catal A Gen 396:68–75. doi: 10.1016/j.apcata.2011.01.037 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Yuji Ohkubo
    • 1
  • Satoru Kageyama
    • 1
  • Satoshi Seino
    • 1
  • Takashi Nakagawa
    • 1
  • Junichiro Kugai
    • 1
  • Hiroaki Nitani
    • 2
  • Koji Ueno
    • 3
  • Takao A. Yamamoto
    • 1
  1. 1.Graduate School of EngineeringOsaka UniversitySuitaJapan
  2. 2.Institute of Materials Structure ScienceHigh Energy Accelerator Research Organization (KEK)TsukubaJapan
  3. 3.Japan Electron Beam Irradiation Service LtdIzumiohtsuJapan

Personalised recommendations