fig6

Figure 6. Symmetric catalytic electrode pairs for the concerted H₂O₂ production: (A) XPS depth profile analysis in the O 1s region for PSF and D-PSFZ and the corresponding O_v/O_l ratio upon the depth as the footnote; (B) 2e^- ORR FE of D-PSFZ at the various solution concentrations of 0.1 to 2.0 M and saturated KHCO₃ solution; (C) The stability profile for D-PSFZ||D-PSFZ E_cell measured in O₂ saturated 2.0 M KHCO₃/K₂CO₃ at 50 mA cm^-2; (A-C) are adapted with permission from^[25]. Copyright © 2023 Springer Nature. (D) The TEM image of TiO_x@MCHS; (E) Fourier transform Ti K-edge EXAFS profiles of TiO_x@MCHS, Ti foil, and TiO₂; (F) The XPS Ti 2p spectra of TiO_x@MCHS; (G) The FE of H₂O₂ for 2e^- WOR over different catalysts as a function of potential tested in 1 M Na₂CO₃; (H) The FE of 2e^- ORR for H₂O₂ on TiO_x@MCHS at different potentials performed in a 1 M KOH or 3.5 M K₂CO₃ + 0.5 M KHCO₃ solution; (I) The H₂O₂ FE, generation rates and the total voltages of the 2e^- WOR//2e^- ORR cell at constant currents; (J) The FE, generation amounts of H₂O₂ and the cell voltages during long-term stability test at 120 mA (anode current density: 120 mA cm^-2); (D-J) are adapted with permission from^[123]. Copyright © 2025 Wiley-VCH GmbH.