The influence of platinum crystallite size on the electrochemical reduction of oxygen in phosphoric acid

Bregoli, L. J.

doi:10.1016/0013-4686(78)85025-7

Cited by 196 publications

(126 citation statements)

References 5 publications

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“…Apparently, high dispersion of platinum on carbon achieved a much higher electrocatalytic activity for oxygen reduction, indicating that the mass activity of the electrocatalyst increases with increasing the ratio of surface metal atoms. The crystallite size effect reported previously 10 is not observed in this work. On the other hand, uniform distribution of the metal particles on the carbon support is also an important factor in improving the electrocatalytic activity.…”

Section: T H I S J O U R N a L I S © T H E R O Y A L S O C I E T Y O contrasting

confidence: 77%

Novel synthesis of highly active Pt/C cathode electrocatalyst for direct methanol fuel cell

et al. 2003

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A 40 wt% Pt/C cathode electrocatalyst with controlled Pt particle size of ~2.9 nm showing better performance than commercial catalyst for direct methanol fuel cell was prepared by a polyol process with water but without using stabilizing agent.Pt-based electrocatalysts with high loading are usually employed in direct methanol fuel cells (DMFC) as cathode electrocatalysts for oxygen reduction reaction at relatively low temperature. Synthesis of highly dispersed supported platinum with uniform nanoparticle size still remains a challenge, especially for high metal loading. The conventional methods for the synthesis of Pt and Pt alloy electrocatalysts are mainly impregnation 1 and colloid methods such as sulfite-complex route 2 and NR 4+ -stabilized metal colloids route. 3 The impregnation is limited because the average particle size is usually large and the size distribution is broad. Both colloidal routes produced well-homogenized ultrafine Pt electrocatalysts, but the complexity of these synthesis hinders its utilization. 4 Many investigators have contributed much endeavour to search for alternative routes. 5 In this paper, uniform platinum nanoparticles with an average diameter of about 2.9 nm supported on carbon with Pt loading up to 40 wt% were prepared by a modified polyol process. The modified polyol method exhibits the merits of impregnation and colloid procedures, i.e., the preparation method is simple but it is able to control the particle size and distribution. The as-synthesized Pt/C electrocatalyst shows better electrocatalytic activity for oxygen reduction reaction in DMFC than that of the commercial catalyst.The precursor, chloroplatinic acid, was dissolved into ethylene glycol (EG) and mixed with carbon black (Vulcan XC-72R, Cabot Corp., S BET = 236.8 m 2 g 21 ) suspended in distilled water. The mixture was maintained at 403 K in an oil bath for 3 h to ensure the complete reduction of Pt. A flow of argon was passed through the reaction system to remove oxygen and organic by-products. In the course of reaction, the evolved vapour was trapped and collected for GC-MS analysis. The resulting solid was filtered, washed with copious distilled water and dried at 343 K in vacuo. The obtained sample was denoted as 40 wt% Pt/C-EG. † The obtained electrocatalyst contains no stabilizing agent. This feature makes the modified process unique, because applications of the traditional polyol process 6 based on stabilizer such as polyvinyl pyrrolidone (PVP) were restricted in the area of electrocatalysis due to serious agglomeration of metal particles after removing the surfactant at relatively high temperature. Besides, the modified polyol process is carried out in a EG/H 2 O mixed solution, whereas, for the conventional polyol process, a strictly anhydrous organic solution is required. 6 The 40 wt% Pt/C-EG and the commercial 40 wt% Pt/C (Johnson Matthey Corp., denoted as 40 wt% Pt/C-JM) were comparatively tested as cathode electrocatalyst in DMFC. Fig. 1a shows the TEM image of the 40% Pt/C-EG sample. As the image ...

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Section: T H I S J O U R N a L I S © T H E R O Y A L S O C I E T Y O contrasting

confidence: 77%

Novel synthesis of highly active Pt/C cathode electrocatalyst for direct methanol fuel cell

et al. 2003

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“…As reported by Bregoli [24], the mass activity of Of these, only the Pt-Cr [3] and Pt-Cr-Co [4,5] are actually more active than pure Pt when the surface area dependance is accounted for. Thus, the comparison of activity between alloys which have been heat-treated to highly dispersed Pt which has not been heat-treated is misleading; comparison to heat-treated Pt having comparable surface area indicates a much smaller, almost negligible effect of alloying on activity.…”

Section: Extended X-ray Absorption Fine Structure (Exafs)mentioning

confidence: 82%

Structure and activity of Pt-Co alloys as oxygen reduction electrocatalysts

Beard¹,

Ross²

1986

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“…Several works reported that Pt reached a maximum mass specific activity at a mean particle size of 3-5 nm [15][16][17][18], while others observed a straight increase of mass specific activity as Pt particle size decreased [19][20][21]. Peuckert et al [15], for instance, found that the ORR surface specific activity was constant with Pt particle sizes above 4 nm but it dropped by a factor of 20 when the particle size decreased from 3 nm to 1 nm, suggesting around 4 nm be the optimum Pt particle size for the maximum ORR mass specific activity.…”

Section: Introductionmentioning

confidence: 99%

Effect of particle size on the activity and durability of the Pt/C electrocatalyst for proton exchange membrane fuel cells

Zhang

Zhong

et al. 2012

Applied Catalysis B: Environmental

166

110

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a b s t r a c tCarbon supported Pt (Pt/C) with various average particle sizes ranging from sub 3 nm to 6.5 nm were in situ prepared and characterized at the cathode of proton exchange membrane fuel cells (PEMFCs). A clear Pt particle size effect on both the catalytic activity for oxygen reduction reaction (ORR) and the durability of the electrocatalyst was revealed. With the Pt particle size increase, both the surface specific activity and the electrochemical stability of Pt/C improved; however, the mass specific activity of Pt/C is balanced by the electrochemical surface area loss. The reduced occupation of corner and edge atoms on the Pt surface during the Pt particle size increase is believed to weaken the adsorption of the oxygenated species on Pt, and thereafter releases more available active sites for ORR and also renders the Pt surface a stronger resistance against potential cycling. It is therefore proposed that by designing the Pt microstructure with more face atoms on the surface, cathode electrocatalyst with both improved activity and enhanced durability would be developed for PEMFCs.

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The influence of platinum crystallite size on the electrochemical reduction of oxygen in phosphoric acid

Cited by 196 publications

References 5 publications

Novel synthesis of highly active Pt/C cathode electrocatalyst for direct methanol fuel cell

Novel synthesis of highly active Pt/C cathode electrocatalyst for direct methanol fuel cell

Structure and activity of Pt-Co alloys as oxygen reduction electrocatalysts

Effect of particle size on the activity and durability of the Pt/C electrocatalyst for proton exchange membrane fuel cells

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