Search

By the first-principles calculations, the sensitivity of CO, H 2 O and NO adsorption on Au doped SnSe 2 monolayer surface is investigated. The results show that CO and H 2 O molecules are physically adsorbed on Au doped SnSe 2 monolayer and act as donors to transfer 0.012 e and 0.044 e to the substrate, respectively. However, the NO molecule is chemically adsorbed on substrate and acts as an acceptor to obtain 0.116 e from the substrate. In addition, our results also show that the biaxial strain can effectively improve the adsorption energy and charge transfer of gas molecules adsorbed on the substrate surface. Also, the recovery time of desorbed gas molecules on the substrate surface is calculated, and the results indicate that the Au doped SnSe 2 is a perfect sensing material for detection and recovery of CO and NO under −8% strain. • The sensitivity of CO, H 2 O and NO gas molecules to Au doped SnSe 2 monolayer was studied by the first-principles method. • The adsorption stability of gas molecules CO, H 2 O and NO on the Au doped SnSe 2 surface was enhanced in turn. • The biaxial strain can effectively improve the adsorption performance of three gas molecules on the Au doped SnSe 2 surface. • The recovery time of desorbed gas molecules on the Au doped SnSe 2 surface was calculated. • The Au doped SnSe 2 monolayer may be an ideal sensing material for detecting CO and NO molecules. [ABSTRACT FROM AUTHOR]

For the detection and monitoring of hazardous gases, for which two-dimensional material gas-sensitive elements have excellent gas-sensitive properties, the adsorption behavior and electrical response to hazardous gases (NO 2 and SO 2) revealed by MoTe 2 monolayers modified by Cu n , Ag n and Au n (n = 1 to 4) are investigated in this article using first principles. To better simulate the situation under realistic doping, the number of nanoclusters doped ranges from 1–4, while the most stable calculated structure is chosen based on the formation energy. Calculations of the energy band structure, work function, density of states, frontier molecular orbitals and other electronic properties of the adsorbed systems show that the introduction of metal atoms effectively improves the electrical conductivity of the MoTe 2 monolayer, with significant improvements for the gas-sensitive response, as well as increasing the adsorption capacity of the gas. The adsorption strength for NO 2 molecules is higher than that for SO 2 molecules in the three atom-doped systems. By analyzing the electronic and adsorption properties, it is found that Cu atoms show excellent properties among the three metal atoms, especially the Cu 3 system has good adsorption and desorption properties for gases. These studies provide a theoretical basis for preparing high-performance MoTe 2 gas-sensitive elements with selectivity and sensitivity for detecting and removing hazardous gases. [Display omitted] ● Cu 3 -MoTe 2 is a promising material for NO 2 and SO 2 detection. ● The effect of nanoclusters on MoTe 2 monolayer modification is better than that of monatom doping. ● Compared with Ag and Au, simple Cu atom shows excellent performance in gas sensor. [ABSTRACT FROM AUTHOR]

• The performance of NOER for TM supported SnSe 2 monolayer is studied by the first-principles method. • Zr supported SnSe 2 monolayer show a better catalytic activity, and its limiting potentials are -0.11 V. • Sc, Ti, Y and Zr supported SnSe 2 monolayer inhibit the occurrence of hydrogen evolution reaction. The development of efficient catalysts for NO electrocatalytic reduction (NOER) is an effective way to synthesize ammonia and solve environmental pollutants. Now, Pt, Au and other metal surface electrocatalysts still have great challenges for the practical application of NOER due to their high cost. However, using single-atom catalysts (SACs) of low-cost and high catalytic activity to study NOER is relatively rare. Herein, based on first-principles methods, the catalytic performance of a series of transition metal supported on the pure 1T-SnSe 2 monolayer for NOER is systematically studied in this paper. The calculation results show that Sc, Ti, Y, Zr and Hf atoms can stably form SACs on 1T-SnSe 2 monolayer, and the N-O bond can be successfully activated when NO is adsorbed. In addition, the Zr supported 1T-SnSe 2 monolayer (Zr@SnSe 2) has a high catalytic activity for NOER, with a low limiting potential of 0.11 V. Moreover, it is noteworthy that Zr@SnSe 2 inhibits the occurrence of hydrogen evolution reaction (HER). We hope that our work will not only provide a new idea for designing efficient catalysts of NOER, but also provide an effective method to solve the problem of NO environmental pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

• Double impurities (Fe, Mn) co-doped SnSe 2 preferred ferromagnetic couplings. • The through bond spin polarization mechanism was proposed as the origin of ferromagnetic. • The strain can regulate the ferromagnetism and optics of (Fe, Mn) co-doped SnSe 2 system. • The Optical properties of (Fe, Mn) co-doped SnSe 2 system has been researched. • Magnetism and Optical properties are linked by orbital analysis. The magnetic and optical properties for double impurities (Fe, Mn) doped SnSe 2 are investigated by first principles calculations. We calculate that the magnetic moments of Fe and Mn for Fe and Mn mono-doped SnSe 2 are 3.98 μ B and 4.97 μ B , respectively. In the GGA + U method, the ferromagnetism of the (Fe, Mn) co-doped SnSe 2 system prefers the most stable state, which is resulted from the hybridization between Fe:3d, Mn:3d and Se:4p states. In addition, we apply strain to research the magnetism for the (Fe, Mn) co-doped SnSe 2 system in the GGA + U method. We find that the structure of molecule are changed by strain and the ferromagnetism of (Fe, Mn) co-doped SnSe 2 is also significantly improved. The introduction of transition metal (TM = Fe, Mn) can effectively improve electric conductivity. And the adsorption strength of TM doped SnSe 2 is also outstanding enhanced. The deficiency of ultra violet absorption in the doped system is compensated under strain. These results indicate the (Fe, Mn) co-doped SnSe 2 will be a perfect candidate for spintronic devices applications. [ABSTRACT FROM AUTHOR]