Enhanced VOCs adsorption on Group VIII transition metal-doped MoS2: A DFT study

Abstract

Volatile organic compounds (VOCs) represent a significant category of toxic and harmful air pollutants. Among the various abatement techniques available for VOCs, adsorption technology is widely recognized as a cost-effective solution. In this study, density functional theory (DFT) was employed to calculate and compare the adsorption capacities of six typical VOCs on pristine MoS₂ and MoS₂ modified with Group VIII (M_VIII) transition metals atoms. It is found that M_VIII-MoS₂ monolayer demonstrates a significant enhancement in adsorption capabilities for VOCs relative to pristine MoS₂. Among these Group VIII transition metals atoms, Fe, Ru and Os atoms exhibited the most significant VOCs adsorption enhancement, with Fe atoms demonstrating a particularly pronounced effect. This suggests a synergistic interaction between the metal dopants and the substrate. Density of states (DOS) and charge density difference analyses provided further insights into the mechanisms underlying improved adsorption capability. Interestingly, the introduction of M_VIII atoms results in the emergence of a novel state density within the surface state of MoS₂, thereby facilitating enhanced electron transfer between VOCs and the substrate. Charge density difference calculations further corroborated these findings, with certain configurations exhibiting significant electron cloud overlap. Such modification leads to more active electron transfer, thereby increasing the substrate’s affinity for VOC molecules and consequently improving the adsorption efficiency. The findings not only enhance the comprehension of VOC adsorption mechanisms on MoS₂ but also underscore the potential of metal-doped two-dimensional materials for environmental applications.