Methanol oxidation catalysis and substructure of PtRu/C bimetallic nanoparticles synthesized by a radiolytic process

Yamamoto, Takao A.; Kageyama, Satoru; Seino, Satoshi; Nitani, Hiroaki; Nakagawa, Takashi; Horioka, Ryo; Honda, Yuji; Ueno, K.

doi:10.1016/j.apcata.2011.01.037

Cited by 34 publications

(19 citation statements)

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“…This decrease in the size of the PtRu nanoparticles agrees with the previously reported results. [15,24] It also indicates that the addition of NaPH 2 O 2 to the precursor solutions not only decreases the average particle size but also improves the dispersibility of the PtRu nanoparticles on the carbon particles. Both behaviours would be explained using heat of mixing with Pt, Ru, and P. The heat of mixing with Pt and P (¡26 kJ/mol) is less than those of mixing with Pt and Pt (0 kJ/mol), Ru and Ru (0 kJ/mol), and Pt and Ru (¡1 kJ/ mol), [24] which means that PtRu nanoparticles covered with P is stable.…”

Section: Effect Of Increasing the Naph 2 O 2 Input Concentrationsmentioning

confidence: 95%

“…To improve the dispersibility of the PtRu nanoparticles on the carbon particles, sodium phosphinate (NaPH 2 O 2 , Wako Pure Chemical Industries), which is originally used as a size adjuster for Pt and/or PtRu nanoparticles on carbon particles, [15,24,25] was added to the precursor solutions. Thus, the PtRu/C samples were synthesised by an EBIRM under different NaPH 2 O 2 input concentrations while maintaining the Pt and Ru input concentrations at 3.0 mM (an input PtRu-LW of 40 wt%).…”

Section: Effect Of Increasing the Naph 2 O 2 Input Concentrationsmentioning

confidence: 99%

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Mass production of highly loaded and highly dispersed PtRu/C catalysts for methanol oxidation using an electron-beam irradiation reduction method

Ohkubo

Kageyama

Seino

et al. 2015

Journal of Experimental Nanoscience

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An electron-beam irradiation reduction method (EBIRM) is a technique to reduce metal ions in an aqueous solution via irradiation with a high-energy electron beam. In this study, an EBIRM is improved to develop a technique for the mass production of highly loaded and highly dispersed PtRu/C catalysts for use as direct methanol fuel cell anodes. An increase in the Pt and Ru input concentrations increased the loading weight from 9 to 37 wt%; however, the dispersibility of the PtRu nanoparticles on the carbon particles decreased. To improve the low dispersibility, sodium phosphinate was added to the precursor solution and the input amount of carbon particles was decreased. These changes resulted in not only highly loaded but also highly dispersed PtRu/C catalysts. The catalytic activity of the highly loaded and highly dispersed PtRu/C catalysts for methanol oxidation was at least 1.6 times higher than that of the lowly loaded and lowly dispersed PtRu/C catalysts in all voltage range. More than 6000 mg of highly loaded and highly dispersed PtRu/C catalysts were relatively easily obtained, and the average particle size of the PtRu nanoparticles was 1.8 nm. These results demonstrated that the improved EBIRM is effective for the mass production of carbon-supported, highly loaded, and highly dispersed metal nanoparticles.

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Section: Effect Of Increasing the Naph 2 O 2 Input Concentrationsmentioning

confidence: 95%

Section: Effect Of Increasing the Naph 2 O 2 Input Concentrationsmentioning

confidence: 99%

Mass production of highly loaded and highly dispersed PtRu/C catalysts for methanol oxidation using an electron-beam irradiation reduction method

Ohkubo

Kageyama

Seino

et al. 2015

Journal of Experimental Nanoscience

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“…Meanwhile, a radiation-induced reduction method is a simple one-pot process for the synthesis of nanoparticles, which can be carried out in aqueous media without any polymer stabilizer or post-treatment (Belloni 2006;Belloni et al 1998). Our laboratory has synthesized various Pt-based bimetallic nanoparticles and demonstrated that irradiating a high-energy electron beam on a metal precursor solution with support powder dispersed in it yields supported fine nanoparticles only in several seconds of time scale Yamamoto et al 2010Yamamoto et al , 2011. The solvent water is radiochemically decomposed to give hydrated electrons which in turn reduce metal ions to metal nanoparticles: The conditions for the radiolytic synthesis have a large impact on the structure of resulting particles.…”

Section: Introductionmentioning

confidence: 99%

Effect of reduction enhancer on a radiolytic synthesis of carbon-supported Pt–Cu nanoparticles and their structural and electrochemical properties

et al. 2015

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In order to clarify the effect of reduction enhancer on the nanoparticle formation process and their structural and catalytic properties, carbon-supported Pt-Cu nanoparticles were synthesized by electron beam irradiation on an aqueous precursor solution in the presence/absence of reduction enhancer. In the absence of reduction enhancer, tetravalent platinum oxide particles of approximately 1 nm in diameter were formed on carbon support with copper barely precipitated, while in the presence of 2-propanol or ethylene glycol or glucose both platinum and copper precipitated as few-nanometer-sized alloy particles together with copper oxides. It was suggested that the metal nuclei produced upon electron beam irradiation do not have enough lifetime without reduction enhancer due to fast oxidation of the nuclei by oxidizing radicals, while the reduction enhancer scavenges these oxidizing radicals preventing oxidation of metallic clusters and prolonging their lifetime. Ethylene glycol gave smaller and better alloyed particles with less copper oxides compared to 2-propanol since the carbonyl compounds derived from oxidation of ethylene glycol protect metallic clusters from oxidation further prolonging their lifetime. In the electrochemical measurements, the methanol oxidation activities of Pt-Cu/C catalysts were well explained by their structural characteristics.

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“…We have reported successful preparation technique of PtRu/C nanoparticles by using radiochemical process [7][8][9]. In our previous study, we have succeeded in synthesizing PtRu grains with controlled size of ca.…”

Section: Introductionmentioning

confidence: 98%

Improvement of methanol oxidation catalytic activities of radiochemically synthesized PtRu/C nanoparticles by post annealing process

et al. 2014

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Electrode catalysts composed of carbon supported PtRu nanoparticles (PtRu/C) synthesized by radiochemical process were annealed to control the PtRu substructure to enhance catalytic activity. The substructure of the PtRu nanoparticles synthesized by using high-energy electron beam under acidic condition was Pt-rich core/Ru-rich shell type, reflecting the redox potentials of each precursor ions. The material characterization techniques revealed that the reductive annealing led to the mixing of PtRu both in the core and on the surface. The sample with annealing temperature of 300 o C for 5 hour showed the highest methanol oxidation current, 2.3 times higher than that obtained with before annealing.

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Methanol oxidation catalysis and substructure of PtRu/C bimetallic nanoparticles synthesized by a radiolytic process

Cited by 34 publications

References 50 publications

Mass production of highly loaded and highly dispersed PtRu/C catalysts for methanol oxidation using an electron-beam irradiation reduction method

Mass production of highly loaded and highly dispersed PtRu/C catalysts for methanol oxidation using an electron-beam irradiation reduction method

Effect of reduction enhancer on a radiolytic synthesis of carbon-supported Pt–Cu nanoparticles and their structural and electrochemical properties

Improvement of methanol oxidation catalytic activities of radiochemically synthesized PtRu/C nanoparticles by post annealing process

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