Journal of Power Sources 165 (2007) 87–91 Short communication Combinatorial screening and nano-synthesis of platinum binary alloys for oxygen electroreduction Ting He ∗ , Eric Kreidler, Liufeng Xiong, Errun Ding Honda Research Institute USA, Inc., 1381 Kinnear Rd., Columbus, OH 43212, USA Received 10 November 2006; received in revised form 11 December 2006; accepted 12 December 2006 Available online 28 December 2006 Abstract The catalytic oxygen electroreduction properties of platinum alloyed with base metals were screened using a high throughput combinatorial method. Candidate catalysts were identified by comparing the activity–stability–composition relationships between the platinum alloys and a pure platinum standard. Among the alloys studied, PtCo, PtNi, PtZn, and PtCu displayed the highest catalytic activities towards molecular oxygen electroreduction, but suffered from poor chemical stability in acid electrolytes. Alloys based on PtW, PtTi, and PtSe offered modest catalytic activity improvements and good chemical stabilities. In addition to the high throughput discovery, various synthesis technologies were studied to engineer alloy particles on the nanoscale. A good correlation in catalytic activity was found between thin film and carefully engineered powder catalysts. © 2006 Elsevier B.V. All rights reserved. Keywords: Combinatorial; Nano-synthesis; Alloy; Electrocatalyst; Oxygen reduction 1. Introduction Proton exchange membrane fuel cells (PEMFCs) are a promising candidate as an environmentally friendly power source for transportation applications [1–3]. The advantages of PEMFCs over internal combustion engines (ICEs) are a relatively high efficiency, low or zero emissions, and a high energy density. The high efficiency of PEMFCs arises from the direct conversion of chemical energy to electrical energy without the Carnot limitation that applies to thermal engines. Governments and automobile companies have committed bil- lions of dollars to push fuel cells powered vehicles (FCVs) into mass market because of the potential energy crisis and strin- gent government pollution regulations. However, three major issues currently inhibit the mass marketing of PEMFCs in trans- portation, namely, high component costs, a less established refueling infrastructure, and poor durability of the system in ser- vice. The cost and durability issues are predominately related to the electrolyte and electrocatalysts used in PEMFCs. To overcome the material barrier of precious metal based electro- ∗ Corresponding author. Tel.: +1 614 327 4767; fax: +1 614 340 6082. E-mail address: the@honda-ri.com (T. He). catalysts, new electrocatalysts must be developed with reduced precious metal content while maintaining high catalytic activ- ity. Though considerable efforts have been made over past decades to find new catalysts, particularly Pt alloy electro- catalysts, for molecular oxygen electroreduction [4–11], little attention has been paid to the systematic investigation of the activity–stability–composition relationships of these alloys and no clear candidate catalyst has been found for next generation FCVs. Combinatorial high throughput research is becoming more and more popular, both academically and industrially, in phar- maceutical, material, and chemical research. A great deal of applied research has been conducted worldwide involving the rapid testing of large numbers of composite materials with the purpose of finding new beneficial materials [12–18]. On one side, the large number of combination does increase the chance of finding desired materials; however, this method can waste resources and time by creating a large amount of useless data. To avoid wasting resources and to produce more reliable data, as in the case of conventional single-experiment measurements, we have developed a novel high throughput method where the number of experiments is smaller than typical industrial combinatorial research, yet providing data as reliable as from conventional single-experiment [19,20]. 0378-7753/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2006.12.030