Adsorption of Toxic Gases on Transition-Metal-Doped Janus MoSTe Monolayers: A First-Principles Study

Area of Science:

• Materials Science
• Computational Chemistry
• Environmental Science

Background:

• Industrial processes release toxic gases (SO2, CO, H2S, NO2, NH3), posing environmental and health risks.
• Development of sensitive gas-sensing materials is crucial for monitoring and mitigating these threats.
• Two-dimensional Janus MoSTe shows promise due to its unique structure, but its gas sensing capabilities, especially when doped, are underexplored.

Purpose of the Study:

• To investigate the gas adsorption properties of transition metal-doped Janus MoSTe using first-principles calculations.
• To evaluate the potential of these doped materials for toxic gas detection and scavenging applications.
• To analyze the impact of transition metal doping on adsorption energies, electronic properties, and recovery times.

Main Methods:

• Employed first-principles calculations based on density functional theory (DFT).
• Systematically studied the adsorption of toxic gases (SO2, CO, H2S, NO2, NH3) on monolayer MoSTe doped with six transition metals (Ru, Rh, Pd, Os, Ir, Pt).
• Analyzed adsorption energies, electronic band structures, density of states, charge density differences, and estimated recovery times.

Main Results:

• Transition metal doping converted weak physisorption on pristine MoSTe to strong chemisorption, with adsorption energies ranging from -0.791 to -2.382 eV.
• Specific dopants showed high sensitivity: Ir-MoSTe for SO2, Ru-MoSTe for CO, and Os-MoSTe for H2S, NO2, and NH3.
• Strong chemisorption leads to ultrahigh sensitivity but increases desorption energy barriers, potentially hindering room-temperature recovery.

Conclusions:

• Transition-metal-doped Janus MoSTe exhibits excellent potential as a highly sensitive toxic gas sensor.
• These materials are also suitable as efficient toxic gas scavengers due to strong adsorption.
• For sensing applications requiring rapid recovery, a thermally activated approach at moderately elevated temperatures is recommended.