In summary, XAS reveals evidence f or the f ormation of Cu-In or Cu-Sn alloy/intermetallic phases, containing 10-40% In or Sn. There are no indications for Cu oxide phase in the bulk material. In addition, separate In(Ox) or Sn(Ox) phases are always detected in the as-prepared materials. These oxidic phases get (partially) reduced and parts of the In or Sn atoms are likely incorporated into the Cu-In or Cu-Sn alloy during operation at catalytic potentials. The metallic Cu-In phase exhibits a considerable degree of crystallinity, which is no t observed for the Cu-Sn phase. Light blue/green/red/purple colors refer to samples after application of reductive potentials, see SI for details.