This study investigates the adsorption of CO, CO₂, NH₃, NO, and NO₂ gas molecules on mono-layer phosphorene using first-principles calculations. The results indicate that phosphorene exhibits superior sensing performance compared to other 2D materials like graphene and MoS₂. The adsorption strength is found to be highly dependent on the charge transfer between the molecules and phosphorene, with nitrogen-based gases showing the strongest adsorption. Transport properties, calculated using a non-equilibrium Green’s function (NEGF) formalism, reveal significant anisotropy along armchair and zigzag directions, consistent with the anisotropic electronic band structure of phosphorene. The I-V relation shows distinct responses to different gas molecules, making phosphorene a promising candidate for high-performance gas sensors.This study investigates the adsorption of CO, CO₂, NH₃, NO, and NO₂ gas molecules on mono-layer phosphorene using first-principles calculations. The results indicate that phosphorene exhibits superior sensing performance compared to other 2D materials like graphene and MoS₂. The adsorption strength is found to be highly dependent on the charge transfer between the molecules and phosphorene, with nitrogen-based gases showing the strongest adsorption. Transport properties, calculated using a non-equilibrium Green’s function (NEGF) formalism, reveal significant anisotropy along armchair and zigzag directions, consistent with the anisotropic electronic band structure of phosphorene. The I-V relation shows distinct responses to different gas molecules, making phosphorene a promising candidate for high-performance gas sensors.