Electrochemical testing of PAMEC and multimodal characterization of UO₂ WE.

Device ID	Electrode	Electrolyte	Electrochemical analysis method		Imaging and spectral analysis
			Cyclic voltammetry	Amperometry
PAMEC-1	UO2 and PVDF/CB composite electrode	0.1 M NaClO4 (pH 9.5), purged with N2 for 30 minutes	CV scan range −1.0 V to 0.5 V vs. SCE at various scan rates from 10 mV s−1 up to 200 mV s−1	Applied −1.0 V vs. SCE for 400 s prior to CV scans; applied 0.5 V vs. SCE for 13 h after CV scans and followed with −1.0 V vs. SCE for 400 s	In situ SEM/EDS, XPS (E-cell was disassembled in XPS glove box)
PAMEC-2	UO2 and PVDF/CB composite electrode	0.1 M NaClO4 (pH 9.5), purged with N2 for 30 minutes	CV scan range −1.0 V to 0.5 V vs. SCE at 20 mV s−1	Applied −1.0 V vs. SCE for 400 s prior to CV scans; applied 0.5 V vs. SCE for 4 h after CV scans	Ex situ XPS (E-cell was disassembled in XPS glove box)
PAMEC-3	UO2 and PVDF/CB composite electrode	0.1 M NaClO4 (pH 9.5), purged with N2 for 30 minutes	NA	Applied −1.0 V vs. SCE for 400 s prior to anodic oxidation; applied 0.5 V vs. SCE for 4 h	STEM (E-cell was disassembled in atmosphere)
PAMEC-4	UO2 and PVDF/CB composite electrode	0.1 M NaClO4 (pH 9.5), purged with N2 for 30 minutes	NA	Applied −1.0 V vs. SCE for 400 s prior to anodic oxidation; applied 0.5 V vs. SCE for 2.5 h	AFM (E-cell was disassembled in atmosphere)
PAMEC-5	PVDF/CB composite electrode	0.1 M NaClO4 (pH 9.5), purged with N2 for 30 minutes	CV scan range −1.0 V to 0.5 V vs. SCE at 20 mV s−1	Applied −1.0 V vs. SCE for 400 s prior to CV scans	NA
PAMEC-6	PVDF/CB composite electrode	10 mM K4Fe(CN)6 and 10 mM K3Fe(CN)6 in 1.0 M aqueous KNO3	CV scan range −0.3 V to 0.8 V vs. platinum RE at various scan rates from 5 mV s−1 up to 100 mV s−1	Applied −1.0 V vs. SCE for 400 s prior to CV scans	NA