RESEARCH / A0349
Non‐Precious Metal Catalysts with Gradient Oxidative Dual Sites Boost Bimolecular Activation for Catalytic Oxidation Reactions
Read the original paper · 10.1002/anie.202506018 ↗
Source figures may contain other techniques and soft X-ray spectra. C, N and O measurements are outside our current hard-XAFS testing range.
Figure 1. Structural characterizations. a) AC-HAADF-STEM pictures, inverse FFT pattern, and EDS mapping results of Ti─CuO/TiO2. b) Cu 2p XPS spectra of Ti─CuO/TiO2 and CuO/TiO2. c) The Cu K-edge XANES spectra of Ti─CuO/TiO2 and CuO/TiO2 and the references (Cu foil, CuO, and Cu2O). d) The R-space Cu K-edge EXAFS spectra of Ti─CuO/TiO2 and CuO/TiO2 and the references (Cu foil, CuO, and Cu2O). e) Interfacial structure of 2D (right) and 3D (left) isosurfaces of local charge density difference in Ti substituted CuO (111) structure. Electron accumulation and depletion are represented by red and blue areas, respectively. f) Oxygen vacancy formation energy of Cu─O─Cu and Ti─O─Cu in Ti─CuO/TiO2 models. g) DOS of Cu in Cu1─O─Cu and Cu2─O─Ti of Ti─CuO/TiO2 models. The Fermi level (EF) is set to 0 eV. Light blue, dark blue, and red balls represented Ti, Cu, and O atoms, respectively. The CuO loading amount of Ti─CuO/TiO2 is 10 wt% unless otherwise specified.
Figure 4. Mechanism investigation. a) In situ DRIFTS and corresponding MS signals recorded during NH3 oxidation of Ti─CuO/TiO2. b) In situ DRIFTS and corresponding MS signals recorded during NH3 oxidation of CuO/TiO2. c) In situ EXAFS spectra of the transient reaction between O2 and pre-adsorbed NH3 at 200 °C of Ti─CuO/TiO2 and CuO/TiO2. d) Corresponding coordination number of Cu─N/O.