In Situ Fourier Transform Infrared Spectroscopy CO-Probe Method for Evaluating the Surface Electronic Structure of Metal Catalysts

The surface electron structure of metal catalysts plays a crucial role in their catalytic performance. Nevertheless, developing simple and reliable methods to evaluate this structure remains challenging. Here, we introduce an electrochemical in situ Fourier transform infrared spectroscopy (FTIRS) CO adsorption probe method to study the surface structure of Pt-based alloy catalysts. Combined with high-angle annular dark-field scanning transmission electron microscopy, X-ray photoelectron spectroscopy, and the in situ FTIRS CO-probe method, our study demonstrated that the red/blueshift of COad wavenumbers could be attributed to the modifications in the surface Pt electronic structure, resulting in a shift of the d-band center for Pt. This would enhance the d-π* feedback effect between Pt and CO and result in the redshifts of the CO adsorption peaks. This phenomenon can also be observed in transition metal–nitrogen–carbon catalysts, further proving the universality of the in situ FTIRS CO-probe method.