Two-dimensional phosphorus-based binary nanosheets for photocatalyzing water splitting: A first-principles study

Based on the current research on phosphorus-based binary compounds, we designed three two-dimensional (2D) materials, namely P2N2, P3N and 8-P3B monolayers. The stability, mechanical and electronic properties of these 2D crystals were investigated using density functional theory (DFT) method. Our proposed monolayers are all semiconductors and exhibit structural and mechanical anisotropy. The P2N2, P3N and 8-P3B were identified to possess good stability, as demonstrated by their high cohesive energies, positive phonon dispersions, and structural integrity through molecular dynamics simulations at 300?1500 K. The band edges and bandgaps of P2N2, P3N and 8-P3B show different variation under external strains, and P3N with strain modulation become suitable for photocatalyzing water splitting, due to appropriate band alignment, the different spatial distributions of CBM/VBM, long electron-hole (e-h) recombination time, the optical adsorption in visible and UV light region, and high hole mobility. Our systematic studies added new members of phosphorus nitrogen (PN) and phosphorus boron (PB) binary compounds, which are expected to serve as high-efficient photocatalysts for water splitting and flexible nanoelectronic devices.