“…Spectroscopy analysis mainly includes infrared spectroscopy (FTIR), Raman spectroscopy (Ram), ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy X-ray diffraction [57], Fourier transform infrared spectroscopy (FTIR) [58], diffuse reflection infrared Fourier transform spectroscopy (FLEDS), electrochemical impedance spectroscopy (EIS) [59], X-ray absorption near-edge structure (XANES) spectrum, energy dispersive X-spectrum [60], etc. Characterization of the catalyst by spectroscopy technology can explore the physical and chemical properties of single-atom catalysts, also reveal the significant differences between single-atom catalysts and traditional nano-metal catalysts, and further clarify the catalytic reaction mechanism.…”