ChemInform Abstract: Highly Active Iridium/Iridium—Tin/Tin Oxide Heterogeneous Nanoparticles as Alternative Electrocatalysts for the Ethanol Oxidation Reaction.

Abstract

Alternative Electrocatalysts for the Ethanol Oxidation Reaction. -Carbon supported Ir71Sn29 catalysts with an average diameter of 2.7 nm are prepared from mixtures of SnCl2, IrCl3, Sn, ethylene glycol, and water (Ar flow, 130°C, 2 h) followed by mixing the as made Ir71Sn29 particles with carbon black (magnetic stirring, 20°C, 1 h). The samples are characterized by HRTEM, STEM, EELS, XRD, XPS, XAS, EXAFS, electrochemical measurements, and DFT calculations. The catalyst particles consist of an Ir-rich core and an Ir-Sn alloy shell with SnO2 present on the surface, Ir/Ir-Sn/SnO2. The Ir71Sn29/C heterogeneous catalyst exhibits high electrochemical activity toward the ethanol oxidation reaction compared to commercial Pt/C, PtRu/C, and PtSn/C catalysts. The superior electro-activity is related to the high degree of Ir-Sn alloy formation as well as the existence of nonalloyed surface SnO2. These results may have significant impact on direct ethanol fuel cell technology by completely replacing Pt with an alternative low-cost, highly active Ir-based nanocatalyst. -(DU, W.; WANG, Q.; SAXNER, D.; DESKINS, N. A.; SU, D.; KRZANOWSKI, J. E.; FRENKEL, A. I.; TENG*, X.; J. Am. Chem. Soc. 133 (2011) 38, 15172-15183, http://dx.

Phase-segregated Pt–Ni chain-like nanohybrids with high electrocatalytic activity towards methanol oxidation reaction

“…[7][8][9] According to the Hammer-Nørskov model, the binding energy of CO on the metallic catalyst is proportional to the d-band center of the surface atoms. 10,11 Thus, it is reasonable to expect the weakened adsorption of CO on Pt with the downshifted d-band center. Furthermore, studies also revealed that the monolayer-dispersed Pt on the substrate would maximize the electronic modification.…”