Abstract
Ammonia is a harmful air pollutant that is frequently released by industrial activities, agricultural, and waste treatment facilities, posing major threats to human health and the environment. The development of sensitive, selective, and longlasting ammonia sensors is thus critical for accurate air-quality monitoring. Choline chloride-glycerol-based deep eutectic solvents (DESs) are presented as attractive sensing media due to their strong hydrogen-bonding capacity, customizable physicochemical features, and environmental friendliness. DFT computations were used to study the atomistic interactions between ammonia and the choline chloride-glycerol DES. Geometry optimizations were carried out to determine the most stable DES-ammonia complexes, followed by extensive electronic structure investigations. Charge redistribution was visualized using molecular electrostatic potential (MEP) maps, which also identified preferential interaction sites for ammonia adsorption. Mulliken charge analysis offered quantitative information about charge transfer pathways during complex formation, whereas frontier molecular orbital (HOMO-LUMO) study indicated changes in electronic characteristics relevant to sensing performance. The findings show strong and directed interactions between ammonia and DES components, which are predominantly regulated by hydrogen bonding and electrostatic forces, resulting in notable changes in electronic structure upon ammonia attachment. These results demonstrate the suitability of choline chloride-glycerol DESs as active materials for ammonia sensing. Future research will concentrate on dynamic simulations, temperature impacts, and experimental validation to connect atomistic discoveries with practical sensor development.