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First-principles study insights into Janus MoWC-based MXenes for enhanced H2S and NH3 sensing applications
Author(s)
Date Issued
August 1, 2025
Type
Article
Abstract
Gas sensors are vital for environmental monitoring, industrial safety, and public health, enabling the detection of hazardous gases like H2S and NH3, even at low concentrations. This study uses first-principles calculations to investigate the gas-sensing properties of H2S and NH3 gases on MoWC and MoWCO2, revealing key insights into their interaction mechanisms and potential for sensor applications. MoWC demonstrates stronger interactions with the gases compared to MoWCO2, as indicated by higher adsorption energy values. Charge transfer and electron density analysis suggest that the adsorption is primarily driven by charge exchange. The findings indicate that MoWC exhibits a highly sensitivity, undergoing significant work function changes when gas is adsorbed. However, AIMD results indicate that at 500 K, hydrogen atoms from gases attract to the surface and form terminal groups, making it unsuitable as a toxic gas sensor under these conditions. In contrast, MoWCO2 exhibits too fast reversibility with an extremely short recovery time. In addition, we demonstrate that the sensing performance is enhanced by introducing O-vacancies in MoWCO2. The MoWCO2-vac shows increased adsorption energy for H2S and offers appropriate recovery times of 0.330 s with a sensitivity of 7.547 %, making it a suitable candidate for efficient room-temperature sensors. These findings pave the way to improve the potential of Janus MoWC-based MXenes for advanced H2S and NH3 sensing applications.
Citation
Applied Surface Science, 699, 2025