The XANES results are supported by the Cu-EXAFS results. Fit models using an In-or Sn-shell were clearly superior to those using exclusively Cu-shells (see Figure and SI f or details), indicating the formation of Cu-In or Cu-Sn intermetallic phases. The best fitting model and corresponding parameters are shown in Figure and Table . The bulk ratios (Figures ) for the Cu-poor samples, however, are not in accordance with XPS, EDX, or ICP-OES, as for all samplesirrespective of element choice (M: In or Sn), suggested ratios (Cu-poor or -rich), or electrochemical treatment (as-prepared or reduced) -Cu:M atomic ratios of 1.5-9 are obtained in EXAFS, i.e., 10-40% is In or Sn. The discrepancy might stem f rom the f act that Cu-EXAFS only "detects" In or Sn being incorporated into the Cu-phase (by means of successful modeling), but is "blind" against a separate M(Ox) phase, whereas EDX and ICP-OES does not discriminate between phases (while XPS is surf ace-sensitive) and points towards a thermodynamic preferred mixture with low In or Sn amounts. Combining all techniques, one may argue for a core-shell structure with CuM-cores covered by M(Ox)-shells. There is an indication for Sn-enrichment in the course of electrochemical operation (from about 10% Sn before to 20-40% af ter operation), suggesting that parts of the reduced Sn atoms will be embedded into the Cu-Sn (core) structure. Figures 7f and S20 display Cu-EXAFS f or all samples in FT-representation, showing large peaks for Cu-In samples and systematically lower peaks f or the Cu-Sn samples, suggesting a considerable degree of crystallinity in the f ormer and the lack of such in the latter. This is supported by the f act that not only the absolute peak heights are larger f or Cu-In, but also that the ratio between the fourth peak at about 4.8 Å reduced distance and the f irst-shell peak at about 2.2 Å is larger for Cu-In than for Cu-Sn, indicating long-range order, see Figure . Accordingly, EXAFS models including multiple-scattering shells were superior in describing Cu-In, but inferior in describing Cu-Sn. Figures 7f, Figure , and S20c show that the degree of crystallinity is increasing with increasing amounts of In in Cu-In as well as with increasing potential due to In-enrichment. The latter effect is also partially visible in the Cu-Sn spectra. The f irst Cu-shell populations (NCu1) support those findings, in that they are highest in average for pure Cu f oams (10.1), medium for Cu-In f oams (8.7), and lowest for Cu-Sn foams (4.9), see also Table . With the exception of Cu rich In, In-and Sn-shell populations tend to rise after application of reductive potential (suggesting element incorporation), and notably, also the Cu-In and Cu-Sn distances (RIn/Sn) become shorter by 0.03-0.1 Å.