The cleanliness was checked by X-ray photoelectron spectroscopy (XPS). These experiments were conducted at the PM4 beamline of the BESSY II electron storage ring operated by the Helmholtz-Zentrum Berlin (HZB) using the LowDosePES endstation. Polarization-dependent X-ray absorption spectroscopy (XAS) measurements at the N K and Co L edges were carried out in total electron yield mode measuring the sample drain current and orienting the sample at different polar angles with respect to the incoming beam of fixed horizontal polarization. The correction for beamline characteristics of the photon flux was carried out using the drain current from the last beamline mirror or XAS spectra of pristine gold substrates. The XAS spectra were normalized to the same step height well above the absorption edge.