DFT Studies of the Photocatalytic Properties of MoS₂-Doped Boron Nitride Nanotubes for Hydrogen Production

This study investigated the photocatalytic properties of MoS₂-doped boron nitride nanotubes (BNNTs) for overall water splitting using popular density functional theory (DFT). Calculations of the structural, mechanical, electronic, and optical properties of the investigated systems were performed using both the generalized gradient approximation and the GW quasi-particle correction methods. In our calculations, it was observed that only (10, 10) and (12, 12) single-walled BNNTs (SWBNNTs) turned out to be stable toward MoS₂ doping. Electronic property calculations revealed metallic behavior of (10, 10)-MoS₂-doped SWBNNTs, while the band gap of (12, 12) SWBNNT was narrowed to 2.5 eV after MoS₂ doping, which is within the obtained band gaps for other photocatalysts. Hence, MoS₂ influences the conduction band of pure BNNT and improves its photocatalytic properties. The water-splitting photocatalytic behavior is found in (12, 12) MoS₂-doped SWBNNT, which showed higher water oxidation (OH^-/O₂) and reduction (H⁺/H₂) potentials. In addition, optical spectral calculations showed that MoS₂-doped SWBNNT had an optical absorption edge of 2.6 eV and a higher absorption in the visible region. All of the studied properties confirmed MoS₂-doped SWBNNT as a better candidate for next-generation photocatalysts for hydrogen evolution through the overall water-splitting process.