Monolayer PC3: A promising material for environmentally toxic nitrogen-containing multi gases

Selective adhesion of nitrogen-containing toxic gasses on hexagonal boron phosphide monolayer: a computational study

CONTEXT

Various toxic gasses are being released into the environment with the increasing industrialization. However, detecting these gasses at low concentrations has become one of the main challenges in environmental monitoring and protection. Thus, developing sensors with high performance to detect toxic gasses is of utmost significance. For this purpose, researchers have introduced 2D materials thanks to their unique electronic qualities and large specific surface area. Within this piece of research, a hexagonal boron phosphide monolayer (h-BPML) is employed as the substrate material. The adhesion behavior of ambient nitrogen-containing toxic gasses, i.e., N2O, NH3, NO2, and NO, onto the h-BPML is investigated through DFT computations. The adhesion energy values for gasses NO and NO2 were calculated to be - 0.509 and - 0.694 eV on the h-BPML, respectively. Meanwhile, the absorbed energy values for gasses NH3 and N2O were found to be - 0.326 and - 0.119 eV, respectively. The recovery time, DOS, workfunction, and Bader charges were computed based on four optimal adhesion structures. After the absorption of NO on the h-BPML, the value of workfunction of a monolayer decreased from 1.54 to 0.47 eV. This amount of decrease was the greatest among the other gasses absorbed. By comparing the investigated parameters, it can be concluded that the h-BPML has a greater tendency to interact with NO gas compared to other gasses, and it can be proposed as a sensor for NO gas.

METHOD

Within this piece of research, the sensitivity of the h-BPML to four nitrogenous toxic gasses, namely, N2O, NH3, NO2, and NO, was investigated using the DFT with HSE06 hybrid functional by using GAMESS software. For this purpose, we computed the DOS, workfunction, and the Bader charges for the four adhesion systems with most stability.

Monolayer AsC5 as the Promising Hydrogen Storage Material for Clean Energy Applications

One of the critical techniques for developing hydrogen storage applications is the advanced research to build novel two-dimensional materials with significant capacity and effective reversibility. In this work, we perform first-principles unbiased structure search simulations to find a novel AsC5 monolayer with a variety of functionally advantageous characteristics. Based on theoretical simulations, the proposed AsC5 has been found to be energetically, dynamically, and thermally stable, supporting the viability of experiment. Since the coupling between H2 molecules and the AsC5 monolayer is quite weak due to physisorption, it is crucial to be enhanced by thoughtful material design. Hydrogen storage capacity can be greatly enhanced by decorating the AsC5 monolayer with Li atoms. Each Li atom on the AsC5 substrate is shown to be capable of adsorbing up to four H2 molecules with an advantageous average adsorption energy (Ead) of 0.19 eV/H2. The gravimetric density for hydrogen storage adsorption with 16Li and 64 H2 of a Li-decorated AsC5 monolayer is about 9.7 wt%, which is helpful for the possible application in hydrogen storage. It is discovered that the desorption temperature (TD) is much greater than the hydrogen critical point. Therefore, such crucial characteristics make AsC5-Li be a promising candidate for the experimental setup of hydrogen storage.

Rich magnetic phase transitions and completely dual-spin polarization of zigzag PC3 nanoribbons under uniaxial strain

Among many modulation methods, strain engineering is often chosen for nanomaterials to produce tunable band gaps continuously. Inspired by the recently reported two-dimensional material PC₃, we explore the tuning of strain on the spin-dependent transport properties of PC₃ nanoribbons using the first-principle approach. Surprisingly, strain regulation achieves uninterrupted completely dual-spin polarization over a wide energy range near E_F. Analysis reveals that the peculiar transmission spectra arise from the interesting evolution of the band structure, in which strain induces bands to shift and broaden/flatten. This results in triggering the transition of PC₃NRs from bandgap-tunable bipolar magnetic semiconductors to spin-gapless semiconductors to ferromagnetic metals or half-metal magnets. Their unique performance demonstrates great potential in spintronics, and our study is expected to provide ideas and theoretical support for the design and application of novel PC₃-based spintronic devices in the future.

Penta-BeP2 Monolayer: A Superior Sensor for Detecting Toxic Gases in the Air with Excellent Sensitivity, Selectivity, and Reversibility

Directly and quickly detecting toxic gases in the air is urgently needed in industrial production and our daily life. However, the poor gas selectivity and low sensitivity under ambient conditions limit the development of gas sensors. In this work, we demonstrate that the penta-BeP₂ monolayer is an excellent toxic gas sensor by using first-principles calculations. The calculated results show that the semiconducting penta-BeP₂ monolayer can chemisorb toxic gas molecules (including CO, NH₃, NO, and NO₂) with distinct charge transfer (-0.182 to 1.129 e) but negligibly interact with ambient gas molecules (including H₂, N₂, H₂O, O₂, and CO₂), indicating high gas selectivity for primary environmental gases. The calculated I-V curves show that the penta-BeP₂ monolayer exhibits a fast response with toxic gas molecules. Upon interaction with CO, NH₃, NO, and NO₂ molecules at a bias voltage of 0.7 V, the currents are 10.23, 14.48, 32.10, and 129.90 times that of the pristine penta-BeP₂ monolayer, respectively, which induces high sensitivity values of 9.23, 13.48, 31.10, and 128.90, respectively. Moreover, the moderate adsorption energies of all toxic gas molecules guarantee that the penta-BeP₂ monolayer possesses good reversibility at room temperature with a short recovery time. Herein, all of our results indicate that the penta-BeP₂ monolayer could be a superior candidate for sensing toxic gases with high selectivity, sensitivity, and reversibility.

Novel Gas-Sensitive Material for Monitoring the Status of SF6 Gas-Insulated Switches: Gese Monolayer

Detecting the decomposition components of SF6 insulating gas is recognized as an effective means to monitor the operating status of the SF6 insulating switch. In this paper, the adsorption characteristics of a new two-dimensional material GeSe for five SF6 decomposition gases (SO2, SOF2, SO2F2, H2S and HF) are reported by first-principles simulation. Through the analysis of the change of energy band structure, density of states distribution, and gas desorption time, it is found that GeSe has the potential as a gas-sensitive material for the selective detection of SO2F2, and the computational work in this paper provides theoretical guidance for the development of new gas-sensitive sensors applied in monitoring SF6 insulated switches.

Adsorption and Sensing Properties of Dissolved Gas in Oil on Cr-Doped InN Monolayer: A Density Functional Theory Study

Dissolved gas analysis (DGA) is recognized as one of the most reliable methods in transformer fault diagnosis technology. In this paper, three characteristic gases of transformer oil (CO, C2H4, and CH4) were used in conjunction with a Cr-decorated InN monolayer according to first principle calculations. The adsorption performance of Cr–InN for these three gases were studied from several perspectives such as adsorption structures, adsorption energy, electron density, density of state, and band gap structure. The results revealed that the Cr–InN monolayer had good adsorption performance with CO and C2H4, while the band gap of the monolayer slightly changed after the adsorption of CO and C2H4. Additionally, the adsorption property of the Cr–InN monolayer on CH4 was acceptable and a significant response was simultaneously generated. This paper provides the first insights regarding the possibility of Cr-doped InN monolayers for the detection of gases dissolved in oil.