Suppressing Oxygen Adsorption on Bulk Arsenic and 2D Arsenic Nanoflake Surfaces: The Role of Sb Doping

The susceptibility of bulk and exfoliated nanolayered arsenic to oxidation has been a significant obstacle limiting their widespread application and safe disposal. Here we report a controllable antimony-doped (Sb-doped) method via chemical vapor transport (CVT) with SnI₄ as a transport agent to prepare the bulk arsenic. After 96 h of exposure to air, the oxygen content on the surface of Sb-doped arsenic with SnI₄ is 67% lower compared to the undoped arsenic with SnI₄, and 89% lower than the control group (undoped arsenic without SnI₄). Notably, Sb-doped arsenic is found to be easier and better exfoliated into two-dimensional (2D) nanoflakes with an average diameter of approximately 180 nm and a thickness of 4-5 nm. Sb doping reduces the surface oxygen content of exfoliated arsenic nanoflakes by 48% after 48 h of oxidation. Comprehensive experimental investigations combined with first-principles calculations demonstrate that the antioxidation improvements resulting from Sb-doping are due to the decreased adsorption energies of I₂ on the (012) and (003) surfaces of Sb-doped arsenic, while the adsorption energies of O₂ increased compared to the corresponding surfaces of undoped arsenic. The enhanced long-term stability in both bulk and layered Sb-doped arsenic presents a promising avenue for further advanced applications.