In this study, the performance of a two-dimensional Al2C monolayer as an adsorptive medium and material sensor for four harmful pnictogen hydride gas molecules viz. NH3, PH3, AsH3, and SbH3 were researched by utilizing first-principles computations. The adsorption energy of the considered pnictogen hydrides is in the range of −0.43 to −1.19 eV. Adsorption of ammonia on the surface of the Al2C monolayer was the strongest among the studied gases. The high adsorption energy of the studied gas molecules on the Al2C sheet may encourage more toxic pnictogen hydride gas molecules to the adsorbed on the material, thereby expanding the affectability. Given the HSE06 computations, the take-up of gases prompts a substantial change in the energy-gap (Eg) of the desired monolayer, which is more noteworthy for the phosphine than other examined gases. AIMD calculations for pristine Al2C monolayer and the corresponding complexes with NH3 and PH3 moieties at 400 K confirm the thermal stability of the studied systems.
