title: Combinatorial high-throughput screening for highly active Pd-Ir-Ce based ternary catalysts in electrochemical oxygen reduction reaction.
abstract: A combinatorial library having 66 different ternary compositions of Pd-Ir-Ce was prepared via the impregnation method to find the optimum ternary composition with the highest performance toward oxygen reduction reaction (ORR) in acid media. Its performance in ORR activity of the combinatorial array was evaluated through two different combinatorial high-throughput screening methods to gain validity: (1) multielectrode half-cell method and (2) optical screening method. From the combinatorial results, the spot at 79:12:9 for Pd-Ir-Ce (at. %) in the array showed the highest ORR activity. The electrochemical characterizations of the single catalyst demonstrates that the optimized Pd79Ir12Ce9/C catalyst shows 1.5 times the ORR activity compared to that of Pd/C catalyst at 0.85 V (vs. RHE). In the Pd-Ir-Ce based catalysts, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results reveal that Ir and Ce are present in the form of IrO2 and CeO2, respectively, and the electron configuration of Pd is effectively modified through the decoration with IrO2 and CeO2. From the results, we suggest that the electro-modification of Pd through strong metal-metal oxide interaction with IrO2-CeO2 was a reason for the enhanced ORR activity.
authors.affiliation: Department of Chemical and Biomolecular Engineering and ‡Graduate School of EEWS (WCU), Korea Advanced Institute of Science and Technology , Daejeon 305-701, Republic of Korea.
authors.forename: Sung Hyeon
authors.initials: SH
authors.lastname: Park
authors.forename: Chang Hyuck
authors.initials: CH
authors.lastname: Choi
authors.forename: Jae Kang
authors.initials: JK
authors.lastname: Koh
authors.forename: Chanho
authors.initials: C
authors.lastname: Pak
authors.forename: Seon-ah
authors.initials: SA
authors.lastname: Jin
authors.forename: Seong Ihl
authors.initials: SI
authors.lastname: Woo
mesh_terms: D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D055664:Electrochemical Techniques; D007495:Iridium / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*
chemical_list: D002563:Cerium; D007495:Iridium; D010165:Palladium; D010100:Oxygen