RESEARCH / A0485
Surface Nanosteps Modulate the Local Environment of Co Single Atoms to Boost the Electrocatalytic Hydrogen Evolution Reaction
Read the original paper · 10.1021/acscatal.4c05624 ↗
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. High-resolution XPS spectra of (a) Co 2p, (b) P 2p in Co−P3/S-TiO2 and Co−P3O/F-TiO2. (c) Ti 2p XPS spectra of TiO2, P-TiO2, Co−P3O/F-TiO2, and Co−P3/S-TiO2. (d) Co K-edge XANES spectra and (e) corresponding FT EXAFS spectra of Co−P3/S-TiO2, Co−P3O/F- TiO2, reference Co foil, and CoO. (f, g) FT k3-weighted fitting curves of Co−P3/S-TiO2 and Co−P3O/F-TiO2 at the Co K-edge. The inset shows the structure of Co−P3 and Co−P3O. The corresponding wavelet transform (WT) contour plots of the EXAFS signals of (h) Co−P3/S-TiO2 and (i) Co−P3O/F-TiO2.
Figure 4. (a) Computed distribution of the electric field near the surface of nanostepped TiO2 with corner angle of 123°. (b) Computed AC+ concentration. (c) Spin density pattern of Co−P3/S-TiO2 and Co−P3O/F-TiO2 from top view and side view, respectively; yellow represents the increase of electrons. The density of states (DOS) patterns of (d) Co−P3/S-TiO2 and (e) Co−P3O/F-TiO2. (f) Co K-edge XANES spectra and (g) the FT k3-weighted fitting curves of Co−P3/S-TiO2 at the Co K-edge recorded at different conditions during electrocatalytic alkaline HER. (h) In situ electrochemical FT-IR spectra recorded with 1.0 M KOH during electrocatalytic HER. (i) Gibbs free energy profiles of alkaline HER over Co−P3/S-TiO2 and Co−P3O/F-TiO2 following the Volmer−Hervoskery pathway. (j) Corresponding coordination configurations.