Combinatorial screening of anode and cathode electrocatalysts for direct methanol fuel cells

Erik Reddington, Jong Sung Yu, Anthony Sapienza, Benny C. Chan, Bogdan Gurau, Rameshkrishnan Viswanathan, Renxuan Liu, Eugene S. Smotkin, S. Sarangapani, Thomas E. Mallouk

Research output: Contribution to journalConference article

15 Scopus citations

Abstract

Progress in several important electrochemical technologies, including batteries, fuel cells, sensors, and electrosynthesis, is currently materials-limited. A common feature of all electrode reactions is the imbalance (i.e., loss or generation) of ions at the electrode surface. We describe in this paper a method by which excess ions in the electrode diffusion layer can be imaged, and used to identify the best electrode materials from a combinatorial array of compositions. Although in principle this method can be applied to many electrochemical problems, we have focused on finding better electrocatalysts for direct methanol fuel cells (DMFCs). The DMFC performs two half-cell reactions: oxidation of methanol, and reduction of oxygen. Two of the most important problems in DMFCs are the poor performance of the electrocatalysts, and the crossover of methanol from the anode to the cathode side of the cell. An ideal situation would be the simultaneous development of two new catalysts: an anode that oxidizes methanol at low overpotential, and a `methanol-tolerant' cathode that reduces oxygen without oxidizing methanol. Based on previously developed rules for predicting the activity of ternary alloy catalysts, we began searching quaternary combinations of noble metals for the anode, and ruthenium selenide-type materials for the cathode reaction. The anode and cathode reactions generate and consume protons, respectively, creating a substantial pH gradient at the electrode surface. Changes in local pH are imaged by means of an appropriate fluorescent indicator: Ni-PTP for the anode and Eosin Y for the cathode. DMFC testing confirms the utility of the screening method, in that a Pt/Ru/Os/Ir quaternary catalyst was substantially superior to the best binary and ternary catalysts prepared under similar conditions.

Original languageEnglish (US)
Pages (from-to)231-236
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume549
StatePublished - Jan 1 1999
EventProceedings of the 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998' - Boston, MA, USA
Duration: Nov 30 1998Dec 3 1998

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Reddington, E., Yu, J. S., Sapienza, A., Chan, B. C., Gurau, B., Viswanathan, R., Liu, R., Smotkin, E. S., Sarangapani, S., & Mallouk, T. E. (1999). Combinatorial screening of anode and cathode electrocatalysts for direct methanol fuel cells. Materials Research Society Symposium - Proceedings, 549, 231-236.