Fig. 2: Characterization of the photocatalysts.
From: Efficient methane oxidation to formaldehyde via photon–phonon cascade catalysis
a,b, UV–Vis spectra (a) and XRD patterns (b) of ZnO, 0.5Ru-ZnO and 2Ru-ZnO. c, Ru 3d and C 1s high-resolution XPS spectra of ZnO, 0.5Ru-ZnO and 2Ru-ZnO. Sat., satellite peak. d,e, High-resolution TEM images of 0.5Ru-ZnO (d) and 2Ru-ZnO (e). The yellow circles in d highlight the ZnO particles and in e highlight the Ru nanoparticles. f, The element mappings of 0.5Ru-ZnO. Scale bars in d–f, 10 nm. g, HAADF-STEM image of 0.5Ru-ZnO. Scale bar, 2 nm. The yellow circles highlight Ru single atom sites. h, Normalized Ru K-edge XANES spectra of 0.5Ru-ZnO with Ru foil and RuO2 as references. i, Fourier transform (FT) magnitudes of Ru K-edge EXAFS spectra in R space of 0.5Ru-ZnO and references.
