Nitric oxide electrochemical reduction reaction on transition metal-doped MoSi2N4 monolayers

Effect of Vacancy, As, and Sb Dopants on the Gold-Capturing Ability of Cu2S during Gold Collection in Matte Processes

The technique of gold collection in matte can effectively improve the trapping efficiency of precious metals such as gold, silver, and platinum. However, the underlying mechanism of gold collection from high-temperature molten matte is complex and not well understood. In this work, the first-principle calculations were utilized to investigate the adsorption behavior of gold atoms on a Cu2S surface. The effects of vacancies and As and Sb doping on the gold-trapping ability of Cu2S were also explored, and the electronic properties of each adsorption system, including the charge density difference, density of states, and charge transfer, were systematically analyzed. The results show that the Cu-terminated Cu2S(111) surface has the lowest surface energy, and the Au atom is chemically adsorbed on the Cu2S(111) with an adsorption energy of -1.99 eV. The large adsorption strength is primarily ascribed to the strong hybridizations between Au-5d and Cu-3d orbitals. Additionally, the Cu vacancy can significantly weaken the adsorption strength of Cu2S(111) towards Au atoms, while the S vacancy can notably enhance it. Moreover, due to the formation of strong covalent As-Au/Sb-Au bonds, doping As and Sb into Cu2S(111) can enhance the gold-trapping capability of Cu2S, and the Sb doping exhibits superior effectiveness. Our studied results can provide theoretical guidance for improving the gold collection efficiency of Cu2S.

Electronic and Spintronic Properties of Armchair MoSi2N4 Nanoribbons Doped by 3D Transition Metals

Structural and physical properties of armchair MoSi2N4 nanoribbons substitutionally doped by 3d transition metals (TM) at Mo sites are investigated using the density functional theory combined with the non-equilibrium Green's function method. TM doping can convert the nonmagnetic direct semiconductor into device materials of a broad variety, including indirect semiconductors, half semiconductors, metals, and half metals. Furthermore the 100% spin filtering behavior in spin-up and spin-down half metals, a negative differential resistance with peak-to-valley ratio over 140 and a rectification effect with ratio over 130 are predicted, as well as semiconductor behavior with high spin polarization.

Cu-Doped MoSi2 N4 Monolayer as a Potential NH3 Sensor

Cu doped MoSi₂ N₄ monolayer (Cu-MoSi₂ N₄ ) was firstly proposed to analyze adsorption performances of common gas molecules including O₂ , N₂ , CO, NO, NO₂ , CO₂ , SO₂ , H₂ O, NH₃ and CH₄ via density functional theory (DFT) combining with non-equilibrium Green's function (NEGF). The electronic transport calculations indicate that Cu-MoSi₂ N₄ monolayer has high sensitivity for CO, NO, NO₂ and NH₃ molecules. However, only NH₃ molecule adsorbs on the Cu-MoSi₂ N₄ monolayer with moderate strength (-0.55 eV) and desorbs at room temperature (2.36×10^-3  s). Thus, Cu-MoSi₂ N₄ monolayer is demonstrated as a potential NH₃ sensor.

The β-PdBi2 monolayer for efficient electrocatalytic NO reduction to NH3: a computational study

β-PdBi2 was proposed as a novel NORR catalyst for NH3 synthesis with high efficiency and high selectivity, and its catalytic activity can be enhanced by a tensile strain.