RESEARCH / A0188
Catalyst Synthesis with Solution Plasma Enhances CO Selectivity in CO2 Hydrogenation Catalyzed by Highly Dispersed Copper in Mixed Zinc–Zirconium Oxides
Read the original paper · 10.1021/acscatal.6c00270 ↗
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 4. Characterization of structures and copper species on catalysts with 0.37 wt % copper loading. (a) Zr 3d XPS data. (b) Estimated Zr3+ content derived from Zr 3d peak fitting. (c) Cu 2p XPS data. (d) Cu K-edge XANES spectra of catalysts and standard references (Cu foil, Cu2O, CuO). (e) Fourier-transformed k2-weighted EXAFS spectra. (f) EXAFS fitting curves for Cu0.37/ZZO-IM and Cu0.37/ZZO-SPP.
Figure 6. (a) CO2 conversion and selectivity characterizing reaction catalyzed by the bare ZZO support and Cux/ZZO-ESPP (reaction conditions: 300 °C and 3 MPa, H2/CO2/N2 = 3:1:1, GHSV = 15,000 cm3 gcat −1 h−1). (b) Comparison of CO-STY values at various reaction temperatures characterizing the Cux/ZZO-ESPP and Cux/ZZO-SPP catalysts investigated in this work with data reported for copper-containing catalysts Cu/ CexMgy,3 Cu−Zn−Al,62 Ni-in-Cu,63 CuOx,64 and Cu/SiO2,65); platinum-containing catalysts (Pt/TiO2,66 Pt/Al2O3,67 Pt/CeO2,68 K80−Pt/L,69), and others (Fe/CeO2,70 Ni/MgAlOx,71 Co−N−C,53) under CO2 hydrogenation conditions. (c) HAADF-STEM image, (d) k2-weighted FT- EXAFS spectra and (e) Cu K-edge XANES of the used Cu0.37/ZZO-ESPP catalyst after a representative catalytic reaction test. (f) CO-STY characterizing Cu2.27/ZZO-SPP and Cu2.27/ZZO-ESPP catalysts determined under various reaction conditions (300 °C, 3 MPa vs 500 °C, 1 bar). (g) Stability test of Cu2.27/ZZO-SPP and Cu2.27/ZZO-ESPP catalysts (reaction conditions: 500 °C and 1 bar, feed composition: 24 vol % CO2 + 72 vol % H2 + 4 vol % N2), GHSV = 1.2 × 105 cm3 gcat