On the pathway to the broader implementation of low temperature polymer electrolyte fuel cells (PEMCs) their performance, which is defined by the equally important factors of the activity and stability of the electrocatalyst, has to be further improved for meeting the demanding benchmarks. Various studies have been lately conducted directly on PEMFCs as well as ex-situ in order to firstly understand and then improve the stability issues, especially concerning the catalyst on the cathode. This work intends to further enlighten and rationally disentangle the complex interplay between the different aging mechanisms of this electrode and at the same time proposes a new strategy for circumventing considerable active surface area losses by tuning the morphology of the electrocatalytic layer.  For this reason two Pt to carbon supported nanocatalysts are put to the test which are different only in respect to the geometry and nature of the carbon support. Thanks to the combination of several advanced experimental techniques the dominating degradation mechanism of each stage of a demanding/long degradation protocol will be demonstrated. The techniques applied are  namely the rotating disk electrode (RDE) setup for the standard electrochemical characterization, the identical-location transmission electron microscopy (IL-TEM) to demonstrate the consecutive stages of the degradation of identical locations of the electrocatalyst on the nanometer scale, the coupled scanning flow cell (SFC) to an inductively coupled plasma mass spectrometer (ICP-MS) to investigate the dissolution of the Pt catalyst during the degradation process in-situ and the SFC coupled to an online electrochemical mass spectrometer (OLEMS) to study the corrosion process of the carbon support in-situ. For the sake of the application relevant conclusions of this study all the aforementioned techniques were operated in application oriented temperature (60 ^oC). Although dealing with a specific nano-engineered class of materials, the reported results are of high interest for the whole catalysis/energy conversion community, as they offer an alternative pathway for increasing the performance of the electrode by refining the catalytic support.