RESEARCH / A0040
Stabilizing Low-Ruthenium Loaded Cobalt-Based Spinel via Cerium Incorporation for Durable Acidic Oxygen Evolution
Read the original paper · 10.1021/acscatal.6c01688 ↗
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. Structural characterizations of the catalysts. (a) XRD patterns and (b) Raman spectra of RuCe−Co3O4, Ru−Co3O4, Ce−Co3O4, and Co3O4. The right panel is an enlarged view of the corresponding peak. (c) Normalized XANES spectra recorded at the Co K-edge for RuCe−Co3O4, Ru−Co3O4, Co3O4, and Co foil. (d) Corresponding Fourier-transformed k3-weighted Co K-edge EXAFS spectra for RuCe−Co3O4 and Ru−Co3O4. (e) WT analyses of the Co K-edge EXAFS spectra for RuCe−Co3O4 and Ru−Co3O4. (f) Fourier-transformed k2-weighted Ru K-edge EXAFS spectra of RuCe−Co3O4, commercial RuO2, and Ru foil. (g) Co 2p XPS spectra and (h) O 1s XPS spectra for RuCe−Co3O4 and Ru−Co3O4, normalized to ensure equal integrated areas for comparison.
Figure 4. Spectroscopic characterization revealing the origin of enhanced RuCe−Co3O4 catalyst stability. (a) Normalized XANES spectra recorded at the Co K-edge for RuCe−Co3O4 and Ru−Co3O4 before and after 10 h of OER operation (inset: enlarged view of the absorption edge position). (b, c) Corresponding Fourier-transformed k3-weighted Co K-edge EXAFS spectra for (b) RuCe−Co3O4 and (c) Ru−Co3O4 before and after OER tests. (d) Operando Raman spectra of RuCe−Co3O4 collected in 0.1 M HClO4 electrolyte during potential changes. The applied potential (vs RHE, without iR correction) was increased from OCV to 1.856 V and then returned to OCV (denoted as OCV-B). (e) Corresponding Raman contour plots of RuCe−Co3O4. (f) Concentrations of dissolved Ru and Co cations from RuCe−Co3O4 and Ru−Co3O4 during chronopotentiometry at 10 mA cm−2 in 0.1 M HClO4.