Fig. 6: In-situ Raman and theoretical calculations for the OER Mechanism. | Nature Communications

Fig. 6: In-situ Raman and theoretical calculations for the OER Mechanism.

From: Atomically thin high-entropy oxides via naked metal ion self-assembly for proton exchange membrane electrolysis

Fig. 6: In-situ Raman and theoretical calculations for the OER Mechanism.The alternative text for this image may have been generated using AI.

a, b In-situ Raman spectra for RuO2 and RuIrFeCoCrO2 in 0.5 M H2SO4 conducted at continuously changed potentials from the open-circuit potential (OCP) to 1.6 V vs. RHE. c Intensity ratio of Ru3+/Ru4+ (\({{{\rm{I}}}}_{{{{\rm{Ru}}}}^{3+}}\)/\({{{\rm{I}}}}_{{{{\rm{Ru}}}}^{4+}}\)) in (a, b) as a function of applied potential. d schematic of the in-situ DEMS (PTFE, polytetrafluoroethylene). e, f DEMS measurements of 32O and 34O signals from the reaction products for 18O-labeled RuIrFeCoO2 (e) and RuIrFeCoCrO2 (f) in 0.5 M H2SO4 in H216O. g Crystal orbital Hamilton population (COHP) analysis for Ru-O bonds in RuO2 (top) and RuIrFeCoCrO2 (bottom). h Density-of-states (DOS) analysis. i, j The OER reaction pathway on Ru site for RuO2 and Co site for RuIrFeCoCrO2. k Calculated energy barrier diagrams of RuO2 and RuIrFeCoCrO2. l Theoretical overpotential volcano plot for RuO2 and RuIrFeCoCrO2, calculated from the scaling relationship of ∆GOOH = 0.79∆GOH + 3.46 eV. The O, OH and OOH present the corresponding adsorption intermediates. The Co_11, Ir_5, and Ir_19 indicates different atomic sites. The color change from red to blue indicates an increase in overpotentials for OER. The η in (k) and (l) presents the overpotential of OER. The LOM (i) and AEM (j) stand for lattice oxygen mechanism and adsorption oxygen mechanism, respectively.

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