fig9

Figure 9. UHV-FTIR spectra of (A) ZnAl₂O_x and (B) ZnGa₂O_x obtained by firstly adsorbing hydrogen in 1 mbar of H₂ at low temperatures, followed by UHV evacuation and the annealing from -130 to 30 °C; (C) Hydrogen activation diagram on ZnAl₂O_x and ZnGa₂O_x. Reproduced from Ref^[72]. Copyright (2024), with permission from American Chemical Society; (D) Reaction cycle for [Au₁₁Cl₂(dppee)₄]⁺ catalyst in Semi-hydrogenation of alkynes. Reproduced from Ref^[80]. Copyright (2022), with permission from American Chemical Society. UHV-FTIR: Ultra-high vacuum-Fourier transform infrared spectroscopy.