Changes In Electronic Properties Research Articles

Charge transfer dynamics in graphene quantum dot-porphyrin derivative nanohybrids appraised via experimental and theoretical calculations

This article is designed to unveil the electronic and spectroscopic property changes of electron withdrawing/releasing group substituted porphyrins, in porphyrin-graphene quantum dot nanohybrids via experimental and computational calculations. Herein, amino, methyl, fluoro & nitro derivatives of meso substituted Tetraphenylporphyrin referred as TAPP, TMPP, TFPP & TNPP respectively, are synthesized from the corresponding benzaldehydes. Charge transfer dynamics of their nanohybrid systems with graphene quantum dots are investigated by electronic spectroscopy, steady state fluorescence and lifetime decay analysis. Negative Gibb's free energy change and dynamic quenching constants stipulate a photoinduced electron transfer with dynamic quenching mechanism within the nanohybrids under scrutiny. Further the computational calculations with the aid of optimized geometries, scatter plots and energy decomposition analysis reflect the same experimental observations. Both experimental and computational studies show that the electron withdrawing group substituted porphyrins have higher interaction with GQD than the electron releasing group substituted porphyrins.

Radiation-induced defects in the InGaN/GaN superlattice structure

With the molecular dynamics method, this paper investigates radiation-induced defects in the In0.16Ga0.84N/GaN superlattice structure (SLS) and the In0.04Ga0.96N/GaN SLS. In the temporal evolution of cascades, most of vacancies recombine with interstitials. The Monte Carlo simulations about the proportions of PKAs induced by 3 MeV protons were also considered in this work for calculating the weighted averages of surviving defects. For the In0.16Ga0.84N/GaN SLS irradiated by protons, around 82.6 percent of surviving vacancies are Ga vacancies while around 88.9 percent of surviving interstitials are Ga interstitials. For the In0.04Ga0.96N/GaN SLS irradiated by protons, around 87.3 percent of surviving vacancies are Ga vacancies while around 88.6 percent of surviving interstitials are Ga interstitials. N vacancies, N interstitials, and In vacancies also exist in irradiated InGaN/GaN SLS. Details about different types of defects are presented in this paper, which helps explain the microscopic mechanism of irradiated InGaN/GaN SLS. Since different types of defects have different influences on electronic and optical properties, simulations about the proportions of various defects in irradiated InGaN/GaN SLS help experimentalists find the effective factors of radiation-related changes in electronic and optical properties.

Transition metal-decorated MgO nanocages as drug carriers for the chlormethine drug

This paper presents a study on the potential use of transition metal (TM)-decorated MgO nanocages, namely Ni, Pd, and Pt, in improving the efficacy and safety of chlormethine (ClM). The research employs density functional theory calculations to explore the electronic properties and adsorption behavior of ClM on the surface of TM-MgO nanocages. The study also investigates the most reactive sites of ClM and TM-MgO nanocages through molecular electrostatic potential plots. The findings reveal that Ni-MgO causes significant changes in electronic properties upon ClM adsorption, with a decrease in the energy gap of frontier molecular orbitals and an increase in electrical conductivity. Meanwhile, Pd-MgO is a suitable Φ-type sensor for ClM detection. The results suggest that TM-decorated MgO nanocages could enhance the effectiveness and safety of ClM and have the potential to be used as a drug delivery system, thus warranting further investigation.

A first-principles investigation of BF3 and ClF3 gas sensing on N-defected AlN nanosheets

We conducted theoretical calculations to examine the energetic stability of pristine aluminum nitride (AlN) and N-defected AlN nanosheets, along with their structural, electronic, and optical properties, utilizing density functional theory. Furthermore, we explored the adsorption properties of BF3 and ClF3 toxic gases on both pristine AlN and N-defected AlN nanosheets. Our findings reveal that the N-defect on the AlN nanosheet enhances the gas adsorption energies (−1.354 and −13.263 eV) compared to the pristine AlN nanosheet. Additionally, the absolute value of the bandgap for the N-defected AlN nanosheet increases to 3.032 eV, exceeding the 2.997 eV value of the pristine AlN nanosheet. The gas molecules suffer significant deformation due to their interaction with adsorbents. Upon BF3 gas adsorption, the bandgap of the N-defected AlN nanosheet diminishes to zero. Moreover, the recovery time after gas adsorption on the N-defected AlN nanosheet surpasses that of the pristine AlN nanosheet. Both adsorbents showed a high absorption coefficient of over 104 cm−1 in the UV region. Significant peak shifting in the optical spectra of the N-defected AlN nanosheet was observed due to gas adsorption. The pronounced changes in structural, electronic, and optical properties following toxic gas adsorption suggest that N-defected AlN nanosheets are suitable for the adsorption (dissociation) of BF3 (ClF3) gases.

Microscopic effect of iron dosage on the stability of Fe‐doped ettringite

AbstractOne significant aspect that affects the performance of high‐ferrite cement is the incorporation of iron (Fe) atoms and its stabilization into the cement phases. However, the influence of Fe doping on the stability of key phases, particularly on the ettringite, remains largely unexplored requiring deeper insights into the fundamental mechanisms. The present study explored the stability of Fe‐doped AFt structure based on density functional theory calculations at different Fe dosage. The obtained results showed that the stability of AFt structure decreases by increasing Fe dosage, which is in good agreement with the previous experimental observations. The incorporation of Fe into ettringite induced a series of changes in AFt structural and electronic properties. Bond order analysis underscored stronger covalent Fe–O bonds compared to Al–O, further emphasizing changes in the material's bonding network. Notably, density of states (DOS) analysis highlights the emergence of new occupied states near the Fermi level, primarily contributed by Fe and O atoms. This increased DOS, coupled with higher electron mobility, correlates with a reduction in material stability, as observed through shifts in bonding interactions and alterations in the bonding network. These findings point toward a complex interplay of factors, including altered bonding characteristics, increased electron mobility, and changes in the electronic structure, contributing to the observed instability of Fe‐doped ettringite.

An experimental and theoretical aided 2D MoS2 nanoflowers strategy for rapid visual sensing of Gallic acid in food and clinical matrixes

Gallic acid (GA), an important phenolic component, is gaining popularity due to its biological and industrial applications. However, its rapid expansion can be hazardous, causing cancer and gene damage, making the design of a low-cost and fast GA sensor difficult. We used a single-step hydrothermal approach to synthesize MoS2 nanoparticles for colorimetric detection of GA. The nanoparticles were analyzed using techniques like; UV–Vis spectroscopy, FT-IR spectroscopy, SEM, EDX and XRD. The optimization of key parameters such as MoS2 concentration (2.0 mg), temperature (30 °C), and pH (7) resulted in a limit of detection (LOD) of 0.125 × 10−6 M with a dynamic range of 0.5 to 36 × 10−6 M. MoS2 nanoflowers performed as nanozymes in the filter paper-based sensor, catalyzing 3, 3′, 5, 5′-tetramethylbenzidine (TMB) oxidation, while GA acted as an inhibitor to prevent further reaction progression. The detection was made feasible through capturing an image support by an ordinary smartphone and the steady-state kinetic study validated MoS2 nanoflowers' affinity for sensing H2O2. The sensor performed well in real-world samples such as diet tea, green tea, water, blood serum, and urine, with recovery rates ranging from 93.2 % to 102.1 %. Density functional theory calculations were applied to provide an insight into GA-MoS2 binding interactions and changes in electronic properties. With all of these merits, we believe MoS2 nanoparticles can provide low-cost and portable filter paper-based strips as a sensing platform for visual assessment of GA.

Radiation induced changes in chemical and electronic properties of few-layer MoS2 and MoTe2 films

We investigate the changes in chemical and electronic properties of partially oxidized MoS2 and MoTe2 films of a few atomic layers during X-ray photoelectron spectroscopy (XPS) measurements at different power densities and exposure times. Our results show that MoTe2 films undergo severe photon-induced chemical changes from surface TeO2 to MoTe2 by Te-O dissociation, while MoS2 undergoes much less change. We find that the reduction of p-dopant TeO2 in MoTe2 results in an upward shift of the Fermi level due to electron injection. These electronic changes in the materials can lead to misleading interpretations of device performance and operating mechanisms during operando analysis. To minimize the damage, we propose two protocols, namely “unscanned mode” and “raster mode”, with high X-ray power density and short acquisition time. These protocols enable reliable operando-XPS analysis of 2D FETs using high photon flux and allow intermediate states to be observed under device operation within seconds to minutes.

Efficient detection of specific volatile organic compounds associated with COVID-19 using CrX2 (X = Se, Te) monolayers

Motivated by the necessity of efficient detection of COVID-19 through specific biomarkers, such as ethyl butyrate and heptanal, we performed first principles calculations based on density functional theory (DFT) to explore the sensing mechanism of pure, vacancy-induced, and single atom catalyzed CrX2 (X = Se, Te) monolayers. Both the biomarkers barely bind on pristine CrSe2. However with Se-vacancy (As-doping) suitable adsorption energies of −1.44 (−0.70), and −0.70 (−0.54) eV were obtained for ethyl butyrate and heptanal, respectively. Te-vacancy (Sn-doping) in CrTe2 resulted in much stronger binding of ethyl butyrate and heptanal with the adsorption energies of −2.04 (−2.40), and −2.90 (−2.40) eV, respectively. The adsorption of the mentioned biomarkers altered the magnetic and electronic properties of defected CrX2, which were explored through spin-polarized density of states, electrostatic potential and work function calculations. Measurable changes in electronic and magnetic properties confirmed excellent sensing potential of CrX2. Statistical thermodynamics analysis based on Langmuir adsorption model was employed to study the sensing of the biomarkers at different temperature and pressure ranges for real-world application.

Two-dimensional ferromagnetism induced by Jahn-Teller distortion and orbital order

As the dimension of the system decreases, the quantum confinement effect and electronic correlation interaction inside the material will be correspondingly enhanced, often resulting in some novel physical properties. Recently, the freestanding perovskite oxide films down to the monolayer limit have been successfully prepared and can be transferred to any desired substrate, providing a great opportunity to explore the functional properties of two-dimensional perovskites. In perovskite materials, Jahn-Teller distortion and orbital order often cause a variety of correlated electronic behaviors. However, unlike van der Waals materials that retain their structural and chemical bonding characteristics when reduced to the monolayer limit, perovskite materials may undergo structural reconstruction when reduced to two dimensions. Therefore, whether Jahn-Teller distortion and related effects exist in the perovskite monolayer limit, and whether two-dimensional perovskite can exhibit some new properties different from its bulk phase, have become urgent issues to be solved. In this work, perovskite fluoride KCuF<sub>3</sub> and its monolayer have been comparatively studied by means of first-principles calculation, symmetry analysis, and Monte Carlo simulation methods, to reveal the change in lattice dynamics, structural, electronic, and magnetic properties caused by dimensionality reduction in perovskites. The results show that the cooperative Jahn-Teller distortion and the in-plane staggered orbital order occurring in the KCuF<sub>3</sub> bulk can be retained to the monolayer limit. However, unlike the bulk phase, the Jahn-Teller distortion mode appears as a soft mode of the prototype phase in the monolayer, and the insulating property of the monolayer does not rely on the emergence of the Jahn-Teller distortion, but is related to the enhancement of the electronic correlation effect. The staggered orbital order causes the nearest-neighbor exchange interaction to be ferromagnetic, resulting in the monolayer being a two-dimensional ferromagnetic insulator, different from the antiferromagnetic phase in the bulk. Monte Carlo simulations predict that the Curie temperature of the monolayer is about 5 K, which is much lower than the Néel temperature of the bulk phase, indicating that the disappearance of interlayer coupling leads to a significant reduction in the magnetic phase transition temperature. This work provides guidance and reference for the study of two-dimensional perovskite materials and the design of perovskite-based two-dimensional ferromagnets.

Construction of Dual-atom catalysts on MoTe2 monolayer to achieve high-efficiency OER/ORR performance

Developing efficient, economical and environmentally friendly multifunctional electrocatalysts is a prerequisite for developing renewable energy conversion and storage technologies. Dual-atom catalysts have significant catalytic performance compared to monoatomic catalysts due to the larger metal loading and synergistic effects between metal atoms, and the reduction of overpotentials and increase of the reaction rate are the keys to obtaining high-performance OER/ORR bifunctional electrocatalysts, as determined by the electrocatalytic thermodynamics and kinetics of electrocatalysis. This work investigates efficient electrocatalysts with bifunctional catalytic activity for OER/ORR. Modifying the MoTe2 material by doping with transition metal atoms shows that the catalysts exhibit better electrochemical stability due to higher solvation potentials. The Pd2@MoTe2 catalysts were screened for bifunctional electrocatalysts due to the change in the local chemical environments. The Pd2@MoTe2 catalysts have excellent bifunctional electrocatalytic activity with overpotentials for OER and ORR of 0.23 and 0.21 V. The results show it can compete with and outperform the currently developed catalysts. This excellent catalytic activity can be attributed to the change in the coordination environment around the modified material, resulting in a change in electronic properties. This effectively ensures excellent electrical conductivity and electron transfer to modulate the strength of adsorbate interactions and optimize the catalytic performance. This work provides new ideas for understanding and optimizing the active center of bifunctional catalysts and new strategies for designing high-performance multifunctional electrocatalysts for metal-air batteries.

Oxygen vacancies mediated changes in ferromagnetic, optical, Photoluminescent and electronic structure properties of Ho-doped CeO2 nanoparticles

The undoped CeO2 and Ce1-xHoxO2 (x = 0.03, 0.05 and 0.07) nanoparticles prepared using microwave assisted co-precipitation route are investigated using X-Ray Diffraction (XRD), UV–Vis–NIR, Raman, photoluminescence, X-ray Photoelectron Spectroscopy (XPS) and SQUID-VSM magnetometer. The XRD validates the inclusion of Ho3+ at the Ce3+/Ce4+ site while maintaining the crystal structure with development of defects and oxygen vacancies with expansion of the CeO2 nanolattice. The composition of the elements with desired stoichiometry is confirmed by Energy Dispersive X-ray spectra analysis. The absorption spectroscopy analysis reports the Urbach energy along with refractive index increases with Ho3+ doping and the optical band gap is decreased indicating red shift. All the nanoparticles are subjected to PL investigations to ascertain the oxygen vacancy and defect structure of nanoparticles. Raman active modes at ∼500 - 630 cm−1 verifies the existence of oxygen vacancies (Vo)., which are seen to rise with concentration of Ho-doping in the CeO2 lattice. When Ce4+ transforms into Ce3+, oxygen vacancies are generated in the lattice to maintain the charge neutrality, as can be seen by the Ce-3d, O-1s, and Ho-4d core level XPS spectra. To demonstrate that Ho3+ doping favours ferromagnetic ordering in the CeO2 lattice, the magnetic properties using the Bound Magnetic Polaron model and F centre exchange mechanism are discussed. The development of various complexes that involve host and doped cations are mediated by Vo suggests the existence of F0, F+, and F2+ centres. The weak ferromagnetic behaviour in Ho3+-doped CeO2 nanoparticles reinforce the relationship between Vo to explain the observed magnetic properties of nanoparticles.

Influence of main-group elements on structural, electronic, magnetic and half-metallic properties of DO3-type Mn3Z (Z = Al, Ga, In, Si, Ge, Sn, P, As and Sb) alloys - A DFT study

We investigate the influence of main-group elements belonging to group III (Al, Ga and In), IV (Si, Ge and Sn) and V (P, As and Sb) on structural, electronic, magnetic and half-metallic (HM) properties of DO3-type Mn3Z alloys using density functional theory (DFT). In particular, we emphasize on the correlation between structural parameters (lattice constant) and the changes in electronic and magnetic properties of Mn3Z alloys. From full geometry optimization results, we find that the entire Mn3Z alloys stabilized to ferrimagnetic ordering. Further, the spin-polarized density of states (DOS) calculation reveals that Mn3Z (Z = Al, Si, Ge, Sn, As and Sb), Mn3Ga and Mn3In alloys exhibit, respectively, half-metallic (HM), nearly half-metallic (NHM) and metallic nature. While, the Mn3P alloy displays spin-gapless semiconducting (SGS) feature, in which spin-up and spin-down channels show metallic and spin-gapless feature, respectively. The Mn3Al, Mn3Z (Z = Si, Ge and Sn) and Mn3Z (Z = P, As and Sb) alloys follow Slater-Pauling rule well, and gives 100 % spin-polarization at the Fermi energy (EF) with total integer magnetic moment of 0, 1 and 2 μB/f.u, respectively. The contribution to total magnetic moment in all the Mn3Z alloys comes predominantly from Mn(Y) atoms. The molecular orbital (MO) hybridization mechanism is proposed to rationalize the HM band gap.

B3C2P3 monolayers based highly sensitive and selective room-temperature gas sensors for reusable NO and NO2 detection

Motivated by the development of high-performance gas sensors using two-dimensional (2D) nanomaterials, herein using the combination methods of density functional theory (DFT) and nonequilibrium Green's function (NEGF), the structural, electronic, transport, and gas sensing properties of the B3C2P3 monolayer adsorbed with various gases (NO2, NO, NH3, SO2, H2S, CO2, CO, H2O, O2 and CH2O) have been systematically studied. The NO2 (or NO) molecules were chemically adsorbed (or strong physisorbed) on the B3C2P3 monolayer, while other molecules were weak-physically adsorbed on the substrate. Furthermore, only the NO2 and NO adsorption results in the remarkable change in electronic properties of B3C2P3. The transport properties such as current-voltage (I–V) characteristics and transmission functions indicate the B3C2P3 monolayer is highly sensitive and selective towards NO2 and NO gases. The recovery times of NO2 and NO were calculated to be 2.27 and 0.0785 ms at 300 K, indicating the reusability of the B3C2P3-based NO2 (NO) sensors. The existence of moisture hardly influences the adsorption of NO and NO2 on the B3C2P3 monolayer. Our results indicated that the B3C2P3 monolayer, as a room-temperature reusable gas sensor, is highly sensitive and selective for NO2 and NO detection regardless of the existence of moisture, O2 and CO2.

Doped HfOx Nanoclusters: Polar and Resistive Switching in the Smallest Functional Units

In the study presented in this article, the impact of proton doping on the structural and electronic properties of hafnium oxide nanoclusters is investigated, with a focus on their potential for use in resistive and polar switching devices. In the results, it is shown that the incorporation of protons can stabilize the cage‐like crystalline structures of clusters, leading to reversible changes in electronic properties by varying oxygen stoichiometry. However, the full coverage of hafnia atoms by hydrogen removes in‐gap states, highlighting the importance of controlled moisture content in redox‐based memristive devices and neuromorphic units. In addition, in this study, the polar properties of these clusters are explored, illustrating possible polar switching in metastable pure , low‐barrier antiferroelectric‐like switching in carbon‐stabilized , and low‐barrier polar switching in . In these findings, the potential of clusters is revealed as active components for next‐generation high‐capacity nonvolatile electronic memory and beyond von Neumann computing in sub‐nanometer scale.

Electronic Properties and Interlayer Interactions in Antimony Oxide Homo‐ and Heterobilayers

Antimony shows promise as a 2D mono‐elemental crystal, referred to as antimonene. When exposed to ambient conditions, antimonene layers react with oxygen, forming new crystal structures, leading to significant changes in electronic properties. These changes are influenced by the degree of oxidation. Utilizing density‐functional theory calculations, stable configurations of bilayer antimony oxide and their corresponding electronic properties are studied. Additionally, different stacking arrangements and their effects on the physical properties of the materials are investigated. Furthermore, the analysis encompasses strain‐free heterobilayers containing both pristine and oxidized antimonene layers, aiming to understand the interplay between these materials and their collective impact on the bilayer properties. In the results, insight is provided into how the properties of antimony‐based bilayer structures can be modified by adjusting stoichiometry and stacking configurations.

Blue phosphorus phase GeSe monolayer for nitrogenous toxic gas sensing: A DFT study

Continuing industrialization, a variety of toxic gases are emitted into the air, yet gas concentrations at low levels are extremely hard to detect. So the development of high-performance toxic gas sensors is imminent. Two-dimensional materials with advantages such as large specific surface area and unique electronic properties open new paths for gas sensors. In this study, a monolayer of blue phosphorus phase germanium selenide (GeSe) was used as the substrate material. The absorption performance of ambient nitrogenous toxic gases (NO, NO2, NH3, N2O) on the surface of GeSe monolayers was explored by the density-functional theory (DFT) calculations. The results show that the interaction between GeSe and the four gases exhibits physisorption. Based on four optimal adsorption structures, Bader charge, work function, band structure, density of states, and recovery time were calculated. Charge transfer is promoted due to the presence of GeSe intrinsic dipoles and only NH3 was found to be the charge donor. The significant changes in work function and electronic properties of GeSe monolayer adsorption of NO indicate significant changes in electrical signals during gas detection. This work reveals that GeSe monolayer has higher sensitivity and selectivity for NO hazardous gas.

Boron-induced phase transformation of ternary cerium boron silicides

Samples of the alloys CeSi2–хBх (x = 0, 0.1, 0.2, 0.4, and 0.5) were prepared and their crystal structures, electrical and magnetic properties were determined. Depending on the amount of boron, x, the phases CeSi2–хBх crystallize in the α-ThSi2 structure type (x = 0, 0.1), or in the α-GdSi2 structure type (x = 0.2, 0.4). Interestingly, as determined by means of X-ray single crystal diffraction crystallizes, CeSi1·5B0.5 crystallizes in the AlB2 structure type (space group P6/mmm, a = 3.9922(2), c = 4.3053(4) Å, 191 reflections with Io ≥ 2σ(Io), R1 = 0.019, wR2 = 0.042). Measurements of the electrical and magnetic properties indicate that phases CeSi2-xBx (x = 0, 0.1, 0.2, 0.4, 0.5) are metallic in character and that phases with B substitution x ≥ 0.2 exhibit correlated magnetic behavior, typically below ∼15 K. Density functional theory calculations were performed to elucidate the change of electronic and physical properties upon boron substitution.

Stoichiometry ratio-induced structural and electronic properties changes of TaN thin films prepared by reactive magnetron sputtering

Tantalum nitride (TaN) is a representative compound with a variety of compositions and mesoscopic phases, which ultimately leads to a diversity of properties. In order to explore relationship between the stoichiometry and properties, in this work, TaN thin films were prepared by reactive sputtering and modulated by controlling the percentage of nitrogen (PN2). All the prepared films were dense and uniform, which exhibited a δ-TaN phase structure. The decrease of nitrogen vacancies directly caused the slightly shift of XRD diffraction peaks and the increase in grain size, both of which showed a lattice distortion of the films. It is also found that the presence of nitrogen vacancies affectes the distribution of the Ta cation as well as the nitrogen-tantalum stoichiometry ratios, so that the deficient material exhibits different electrical properties. The TCR of TaN in this work achieved as low as 32.9 ppm/°C (nitrogen-tantalum ratio of 0.843), which is attributed to the nitrogen vacancies in TaN lattice effectively regulating the electron scattering in the vicinity of Ta atoms. Meanwhile, the change in resistivity is only 1 %, indicating a good long-term stability of TaN. This study provides a point of reference for the preparation of film resistors from the perspective of material modulation.

Stable acidic water oxidation by tunable electronic states in β-PbO2 anode electrocatalyst aided by incorporation of various anions and cations

Developing stable and cost-effective electrodes is one of the main challenges of clean hydrogen fuel production. However, the investigation of non-precious materials for this application, from both experimental and theoretical aspects, has been limited in scope. In the present research, the lead dioxide (β-PbO2) electrode was prepared by an anodic electrodeposition method on Ti substrate to use as the anode in electrochemical water splitting cells, where the oxygen evolution half-reaction occurs. The substitution of F– anion and Fe3+ and Co2+ cations into the structure of lead dioxide, to improve the properties and performance of these anodes, was investigated through a combination of experimental studies and quantum mechanical (QM) calculations. The β-PbO2, β-PbO2-F, β-PbO2-Fe, and β-PbO2-Co electrodes were characterized by the XRD, SEM, EDS, and electrochemical analyses, including CV, LSV, CP, and EIS. Furthermore, the electrode structures were investigated in theoretical studies by the density functional theory (DFT) method. The Gibbs energy change of intermediates formation and electronic properties, including band structure, the density of states, and charge density difference, were calculated and studied. The results showed that the substitutional elements improved the PbO2 activity toward oxygen evolution reaction (OER) by reducing the intermediates' adsorption resistance from 84.2 in pure PbO2 to 11.7 Ω.cm2 in PbO2-Fe. Fe3+ substitution had the most effect on durability and increased the efficient lifetime of the anode about 4 times relative to pure PbO2. The electrochemically active surface area (ECSA) was also increased intensively by doping Fe3+. It is concluded from the DFT calculations that the reaction energy barriers are reduced by ion incorporation. The OER overpotential decreases significantly from 920 mV on pure PbO2 surface to 350 mV by Co2+ substitution. The enhancement of the intrinsic activity of cation-substituted anodes was evidenced by the remarkable reduction of band gap energy at the Fermi level.

Adsorption of sulfur-containing contaminant gases by pristine, Cr and Mo doped NbS2 monolayers based on density functional theory

The adsorption and sensor performance of hazardous gases containing sulfur (SO2, H2S and SO3) on pristine, Cr and Mo doped NbS2 monolayers (Cr-NbS2 and Mo-NbS2) were investigated in detail based on density functional theory. The comparative analysis of the parameters such as density of states, adsorption energy, charge transfer, recovery time and work function of the systems showed that the pristine NbS2 monolayer have poor sensor performance for sulfur-containing hazardous gases due to weak adsorption capacity, insignificant charge transfer and insignificant changes in electronic properties after gas adsorption on the surface. After doping with Cr atoms, the adsorption performance of Cr-NbS2 was significantly improved, and it can be used as a sensor for SO2 and H2S gases and as an adsorbent for SO3 gas. The adsorption performance of Mo-NbS2 is also significantly improved by doping with Mo atoms, and it can be used as a sensor for H2S gas and as an adsorbent for SO2 and SO3 gas. Therefore, Cr-NbS2 and Mo-NbS2 are revealed to be sensing or elimination materials for the harmful gases containing sulfur (SO2, H2S and SO3) in the atmosphere.