RESEARCH / A0480
Revealing the Dynamics of Oxygen Vacancy in ZnO1–x/Cu during Robust Methanol Synthesis from CO2
Read the original paper · 10.1021/acscatal.4c01648 ↗
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 2. Identification and quantification of oxygen vacancy. (a) Normalized XANES spectra of ZnO1−x/Cu catalysts and references of ZnO and Zn foil at the Zn K edge and (b) the corresponding k3-weighted FT-EXAFS spectra in R-space. (c) Fitting coordination numbers(CN) results of Zn−O−Zn for ZnO1−x/Cu catalysts and corresponding wavelet transform plots. (d) Cu 2p XPS and Cu LMM AES spectra of the reduced ZnO1−x/Cu catalysts. (e) Zn 2p XPS and Zn LMM AES spectra of the reduced ZnO1−x/Cu catalysts. (f) Correlation between the oxygen vacancy concentration and Znδ+ and mechanical energy; the error bars indicate the standard deviation of three experimental measurements. (g) Established structures of Zn6O6/Cu and Zn12O12/Cu simulating two different dispersions of ZnO1−x on ZnO1−x/Cu. PDOS projected on the d orbital of the Zn atom and p orbital of the O atom in Zn6O6/Cu (h) and Zn12O12/Cu (i). pCOHP and ICOHP analysis of Zn6O6/Cu (j) and Zn12O12/Cu (k).
Figure 4. Dynamics of oxygen vacancy during CO2 hydrogenation. (a) Normalized XANES spectra of ZnO1−x/Cu-100 during CO2 hydrogenation and references of ZnO and Zn foil at the Zn K edge and (b) the corresponding k3-weighted FT-EXAFS spectra in R-space. (c) Fitting coordination numbers(CN) results of Zn−O−Zn for ZnO1−x/Cu-100 before and during CO2 hydrogenation and corresponding wavelet transform plots. (d) Zn 2p XPS and Zn LMM AES spectra of the ZnO1−x/Cu catalysts during CO2 hydrogenation. (e) Fraction of Znδ+ during CO2 hydrogenation methanol productivity. (f) Correlation between the oxygen vacancy concentration & Znδ+ with methanol productivity. The error bars in (e) and (f) indicate the standard deviations of three experimental measurements.