Au Catalyst-Modified MoS2 Monolayer as a Highly Effective Adsorbent for SO2F2 Gas: A DFT Study

Performance enhancement of gas sensing by modification of molybdenum selenide nanosheets with metal nanoparticles

In this paper, nanostructured molybdenum selenide (MoSe₂) with composited phases are synthesized by hydrothermal method, and the products are modified by metal anoparticles to improve the gas sensing performance. Microstructure characterization shows that few layered 1T/2H-MoSe₂nanosheets have been successfully prepared. Both the morphology and component of nanosheets could be tuned by the reaction parameters. It is shown the MoSe₂-based nanomaterials have excellent selectivity to nitrogen dioxide (NO₂) according to gas sensing properties measurement. The sensitivity of 1T/2H-MoSe₂nanosheets modified by Cu nanoparticles is 17.73 (50 ppm NO₂) at the optimal operating temperature, which is the highest compared with other samples. The sensors also exhibit rapid response/recovery time and high stability. The sensing mechanism of MoSe₂nanosheets toward NO₂is investigated based on the first-principles calculation. The results suggest the modification by metal nanoparticles could significantly improve the adsorption energy and charge transfer between gas molecule and MoSe₂. This work demonstrates a promising guidance for the design of new NO₂gas sensing materials and devices.

First-Principle Study of Rh-Doped Nitrogen Vacancy Boron Nitride Monolayer for Scavenging and Detecting SF6 Decomposition Products

The scavenging and detection of sulfur hexafluoride (SF6) decomposition products (SO2, H2S, SO2F2, SOF2) critically matters to the stable and safe operation of gas-insulated switchgear (GIS) equipment. In this paper, the Rh-doped nitrogen vacancy boron nitride monolayer (Rh-VNBN) is proposed as a gas scavenger and sensor for the above products. The computational processes are applied to investigate the configurations, adsorption and sensing processes, and electronic properties in the gas/Rh-VNBN systems based on the first-principle calculations. The binding energy (Eb) of the Rh-VNBN reaches -8.437 eV, while the adsorption energy (Ead) and band gap (BG) indicate that Rh-VNBN exhibits outstanding adsorption and sensing capabilities. The density of state (DOS) analysis further explains the mechanisms of adsorption and sensing, demonstrating the potential use of Rh-VNBN in sensors and scavengers of SF6 decomposition products. This study is meaningful as it explores new gas scavengers and sensors of SF6 decomposition products to allow the operational status assessment of GIS equipment.

Platinum-Doped Anatase (101) Surface as Promising Gas-Sensor Materials for HF, CS2, and COF2: A Density Functional Theory Study

In order to find promising sensor materials for HF, CS₂, and COF₂ detection to realize the online internal insulation defect diagnosis of a SF₆ gas electrical device, the gas sensing property, binding energy, adsorption distance, charge transfer, and density of states distribution, of Pt-doped anatase TiO₂ (101) surfaces on HF, CS₂, and COF₂ gas molecules was calculated and analyzed in this paper based on the density functional theory. The work suggested that the Pt-TiO₂ surface has a nice gas sensing upon CS₂ and COF₂ because of the increase of the conductivity of the Pt-TiO₂ surface and the suitable adsorption parameter after CS₂ and COF₂ adsorbing on it. However, this material is not suitable as a gas sensor for HF gas. All of the works provide theoretical adsorption information of Pt-TiO₂ as a gas sensor material for HF, CS₂, and COF₂ detection.