Fig. 4: Structural and elemental characterization of ordered mN-WO3. | Nature Communications

Fig. 4: Structural and elemental characterization of ordered mN-WO3.

From: Solvent-pair surfactants enabled assembly of clusters and copolymers towards programmed mesoporous metal oxides

Fig. 4

a, b Typical FESEM (a) and TEM images with a selected-area electron diffraction pattern (b) of ordered mN-WO3. c HRTEM image of mN-WO3, indicative of iso-oriented crystalline walls. d ac-HAADF-STEM image of mN-WO3 produced with fast Fourier transform (FFT) and then reverse FFT. e EDX element mapping analysis of the structure. f XPS spectrum shows the N 1s core level peak region. The inset is structural model of N-WO3 constructed by DFT calculations, revealing the interstitial doping of nitrogen. g XRD patterns of mN-WO3 and mWO3 (the control sample). Both of them are monoclinic WO3, while the refined structure of mN-WO3 is attributed to the ε-phase and the mWO3 is attributed to the γ-phase. h Fourier transform W L3-edge EXAFS spectra of the samples and the inset is W L3-edge EXAFS oscillation function k3c(k). i Response-recovery curves of gas sensors based on mN-WO3 (blue line) and mWO3 (red line) under different acetone concentrations at 300 °C.

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