Quantifying metal support interaction in ceria-supported Pt, PtSn and Ru nanoparticles using electrochemical technique

Electrochemical promotion and metal-support interaction (MSI) have long been viewed as two separate phenomena; however, more recently it has been shown that, functionally, for ionic and mixed ionic-electronic conducting materials, both are linked by the transfer of ionic species at the interfaces. The purpose of this study was to exhibit a relationship between these two concepts through the use of an electro-chemical technique to evaluate CeO2-supported Pt- and Ru-based nanoparticles. The presence of ceria was found to increase the reaction rate when compared to free-standing Pt and Ru nanoparticles with the metal-support interaction rate enhancement ratios, rho(MSI), up to 14. Polarization measurements established that higher exchange current density, i(0), values correspond to lower open circuit catalytic rates. An apparent self-induced Faradaic efficiency was proposed and determined for each catalyst; lowest value (vertical bar Lambda(MSI)vertical bar approximate to 20) was found for free-standing nanoparticles, while highest value (vertical bar Lambda(MSI)vertical bar = 1053) corresponded to 1 wt% Pt-1/CeO2. (C) 2015 Elsevier Inc. All rights reserved.