Abstract: Described herein is a method for manufacturing a catalytically-active membrane-electrode-assembly (20) with one or more, particularly two electrodes, the method comprising at least the steps of: i) depositing a heterogenous layer (3) on a substrate (5), the heterogeneous layer (3) comprising a base metal (1) and a noble metal (2) heterogeneously distributed in the heterogenous layer (3), ii) leaching of the base metal (1) out of the heterogeneous layer (3), such that a first self-supporting nanoporous catalyst layer (4) comprising the noble metal (2) is formed on the substrate (5), iii) adding of at least one kind of proton-conductive ionomers (40) and/or at least one kind of hydrophobic particles (41) and/or an ionic liquid (42) to the first self-supporting nanoporous catalyst layer (4), and iv) forming a catalytically-active membrane-electrode-assembly (20) by attaching the self-supporting nanoporous catalyst layer (4) to a first side of a membrane (10), such that a catalytically-active membrane-electrode-a