Fig. 4: Near-ambient pressure X-ray photoelectron spectra of CuZn NPs on SiO2/Si(100).

a Cu 2p and b Zn 2p regions recorded using a photon energy of 1250 eV. c Copper and zinc atomic fractions obtained under different atmospheres as indicated on the plot. The two-photon energies used for probing the surface (1250 eV) and subsurface (1580 eV) regions of the CuZn NPs are displayed. Error bars correspond to the standard deviation. The inset shows an AFM image of the sample.