Compressive strain as the main origin of enhanced oxygen reduction reaction activity for Pt electrocatalysts on chromium-doped titania support

• Published in: Applied catalysis. B, Environmental Vol. 158-159; pp. 112 - 118
• Main Authors: Kim, Jun-Hyuk, Chang, Seohyoung, Kim, Yong-Tae
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 01.10.2014; Elsevier
• Subjects: Adsorption; Charge transfer; Compressive properties; Lattice strain; Origins; Oxide supports; Oxygen reduction reaction; Platinum; Pt-based fuel cell electrocatalysts; Reduction; Strain; Titanium dioxide; XANES; DOS; Pt-based fuel cell electrocatalysts; PEMFCs; XAS; ECSA; ORR; EXAFS; Oxide supports; DFT; CV; SMSI; Oxygen reduction reaction; FWHM; Lattice strain; XPS; Charge transfer; Cr-TiO2; TEM
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2014.04.003

To date, it has been claimed in several studies that the charge transfer from titania to Pt is the main origin of the enhanced ORR activity, while the theoretical adsorption model suggested that such charge transfer to Pt could lead to stronger OH adsorption and therefore a negative effect on ORR activity. We resolve this controversy by considering a lattice strain effect induced by the strong metal support interaction. •The origin for ORR activity in Pt on titania has been in significant debate.•We resolve this controversy by considering a lattice strain effect.•The main origin is the compressive strain rather than the charge transfer. In this study, we have attempted to clarify the origin of the enhanced oxygen reduction reaction (ORR) activity of Pt on titania supports, which has been the subject of significant debate. To date, it has been claimed in several studies that the charge transfer from titania to Pt is the main origin of the enhanced ORR activity, while the theoretical adsorption model suggested that such charge transfer to Pt could lead to stronger OH adsorption and therefore a negative effect on ORR activity. We resolve this controversy by considering a lattice strain effect induced by the strong metal support interaction. EXAFS studies clearly show that a compressive strain leading to a lower d-band center is exerted on the Pt lattice on the titania-based supports. Hence, we strongly suggest that the main origin for the enhanced ORR activity is the compressive strain rather than the charge transfer.