fig1

Figure 1. Structural characterization of IL-modified Cu-based catalyst. (A) SEM, (B) TEM, and (C) HRTEM images of Cu₂O/CuO-IL catalyst; (D) PXRD patterns of Cu-based catalysts with and without [Omim][BF₄] modification; (E) FT-IR spectra of [Omim][BF₄] and [Omim][BF₄]-modified Cu-based catalysts; (F) TGA curves; (G) Cu 2p, (H) N 1s, and (I) B 1s XPS spectra of Cu-based catalysts with and without [Omim][BF₄] modification. IL: Ionic liquid; SEM: scanning electron microscope; TEM: transmission electron microscope; HRTEM: high-resolution transmission electron microscope; PXRD: powder X-ray diffraction; [Omim][BF₄]: 1-octyl-3-methylimidazolium tetrafluoroborate; FT-IR: Fourier transform infrared; TGA: thermal gravimetric analysis; XPS: X-ray photoelectron spectroscopy.