In Situ Fourier\nTransform Infrared Spectroscopy CO-Probe\nMethod for Evaluating the Surface Electronic Structure of Metal Catalysts

The surface electron structure of metal catalysts plays\na crucial\nrole in their catalytic performance. Nevertheless, developing simple\nand reliable methods to evaluate this structure remains challenging.\nHere, we introduce an electrochemical in situ Fourier transform infrared\nspectroscopy (FTIRS) CO adsorption probe method to study the surface\nstructure of Pt-based alloy catalysts. Combined with high-angle annular\ndark-field scanning transmission electron microscopy, X-ray photoelectron\nspectroscopy, and the in situ FTIRS CO-probe method, our study demonstrated\nthat the red/blueshift of CO<sub>ad</sub> wavenumbers could be attributed\nto the modifications in the surface Pt electronic structure, resulting\nin a shift of the d-band center for Pt. This would enhance the d-π*\nfeedback effect between Pt and CO and result in the redshifts of the\nCO adsorption peaks. This phenomenon can also be observed in transition\nmetal–nitrogen–carbon catalysts, further proving the\nuniversality of the in situ FTIRS CO-probe method.