Revealing surface fine structure on PtAu catalysts by an in situ ATR-SEIRAS CO-probe method

Abstract

The electrochemical performance of Pt-based catalysts depends on their surface structure. Nevertheless, it is still a challenge to investigate their intricate surface-active sites. Here, PtAu films were utilized as model catalysts to understand the surface fine structure and structure–activity relationship. Significantly, the in situ attenuated total reflectance-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) CO-probe method was established to reveal the surface-active sites of PtAu catalysts. By employing the second derivative spectrum (SDP) method and Gaussian fitting for the infrared spectra of the CO oxidation reaction (COR), three surface configurations, the Pt_isoAu, Pt_adjAu site and Pt_richAu site, were unveiled. Additionally, the activity order and reactive species of the COR oxidation peaks were clarified by correlating CO_L intensities with the COR current curves. More importantly, this in situ ATR-SEIRAS CO-probe strategy can be extended from PtAu model films to PtAu nanoparticles.