Simulation Study on the Adsorption Effect of Modified Black Phosphorus on Volatile Organic Compounds.

contextBlack phosphorus (BP) holds promise for gas adsorption, but intrinsic BP often exhibits limited performance. To enhance the limited adsorption performance of intrinsic black phosphorus (BP) towards volatile organic compounds (VOCs), this study investigated the adsorption behaviors of BP doped with ten elements using density functional theory (DFT). Simulations reveal that intrinsic bilayer BP exhibits formaldehyde adsorption energies ranging from - 0.0082 to - 1.6439 eV. Doping significantly improved this performance; notably, Al-doped BP achieved an adsorption energy of - 4.7037 eV at the R-site, nearly tripling the intrinsic value. Mechanism analysis indicated substantial electron transfer from the modified BP to formaldehyde, with Na-, Li-, and Al-doped systems demonstrating charge transfers of - 0.74 e, - 0.71 e, and - 0.70 e, respectively. This redistribution of electron density markedly strengthened interactions with polar molecules. Consequently, the doped systems displayed superior adsorption efficacy for oxygen-containing VOCs compared to non-polar ones, with Li-doped BP attaining a maximum adsorption energy of - 3.8432 eV for acetaldehyde. These findings provide theoretical insights into tuning BP's electronic structure via doping to develop high-performance 2D adsorption materials.

methodsAll calculations used DFT with GGA-PBE and LDA. A plane-wave basis set (480 eV cutoff) and ultrasoft pseudopotentials were used. The Brillouin zone was sampled with a 2 × 2 × 2 k-point grid. Adsorption energies were calculated, and electronic properties like charge density and Mulliken charge transfer were analyzed. All simulations used the CASTEP module in Materials Studio.