  Since its discovery, the environmental instability of exfoliated black
phosphorus (2D bP) has emerged as a challenge that hampers its wide application
in chemistry, physics, and materials science. Many studies have been carried
out to overcome this drawback. Here we show a relevant enhancement of ambient
stability in few-layer bP decorated with nickel nanoparticles as compared to
pristine bP. In detail, the behavior of the Ni-functionalized material exposed
to ambient conditions in the dark is accurately studied by TEM (Transmission
Electron Microscopy), Raman Spectroscopy, and high resolution X-ray
Photoemission and Absorption Spectroscopy. These techniques provide a
morphological and quantitative insight of the oxidation process taking place at
the surface of the bP flakes. In the presence of Ni NPs, the decay time of 2D
bP to phosphorus oxides is more than three time slower compared to pristine bP,
demonstrating an improved structural stability within twenty months of
observation.
