Van Der Waals Dispersion Correction Research Articles

Electronic structure and optical properties of nitrogen-doped antimonene under biaxial strain: first-principles study.

In this thesis, the role of N atom doping and biaxial strain in modulating the electronic structure and optical properties of antimonene has been deeply investigated using a first-principles approach based on density-functional theory. The results show that N doping significantly reduces the band gap of antimonene and introduces new electronic states, thus affecting its electronic structure. In terms of optical properties, N doping reduces the static permittivity of antimonene and alters its absorption, reflection, and energy loss properties. In addition, biaxial strain further enhanced the modulation effect of these properties. This study not only provides theoretical support for the application of antimonene in the field of high-performance two-dimensional electronic and optoelectronic devices, but also reveals strain and doping as an effective means to modulate the physical properties of two-dimensional materials. For the calculations, we used the DFT-based CASTEP software package for the simulation of the electronic structure. In order to more accurately characterize the weak interactions between two-dimensional materials, we specifically introduced the Van der Waals dispersion correction. We have chosen the Perdew-Burke-Ernzerhof (PBE) exchange-correlation generalization under the generalized gradient approximation (GGA) and combined it with the Van der Waals correction term in order to fully consider the electronic structure of antimonene. For the calculation parameter settings, we set the truncation energy to 400 eV to ensure the accuracy of the calculation. Meanwhile, we adopt a 6 × 6 × 1 k-point grid for Brillouin zone sampling to obtain more accurate energy band structure and density of states information. For the convergence settings, the convergence criteria for both the system energy and the interaction force between atoms were set to 1 × 10-5 eV and 0.01 eV/Å, respectively. We selected a 3 × 3 × 1 supercell model with 18 Sb atoms. A vacuum thickness of 18 Å was established in the Z direction, which is sufficient to avoid interactions between the two atomic layers above and below the periodic structure.

Probing interaction of atherogenic lysophosphatidylcholine with functionalized graphene nanosheets: theoretical modelling and experimental validation.

The potential of graphene derivatives for theranostic applications depends on their compatibility with cellular and biomolecular components. Lysophosphatidylcholine (LPC), a lipid component present in oxidized low-density lipoproteins, microvesicles and free circulation in blood, plays a critical role in the pathophysiology of various diseases. Usingdensity functional theory-based methods, we systematically investigated the interaction of atherogenic LPC molecule with different derivatives of graphene, including pristine graphene, graphene with defect, N-doped graphene, amine-functionalized graphene, various graphene oxides and hydroxylated graphene oxides. We observed that the adsorption of LPC on graphene derivatives is highly selective based on the orientation of the functional groups of LPC interacting with the surface of the derivatives. Hydroxylated graphene oxide exhibited the strongest interaction with LPC with adsorption energy of - 2.1 eV due to the interaction between the hydroxyl group on graphene and the phosphate group of LPC. The presence of aqueous medium further enhanced this interaction indicating favourable adsorption of LPC and graphene oxide in biological systems. Such strong interaction leads to substantial change in the electronic structure of the LPC molecule, which results in the activation of this molecule. In contrast, amine-modified graphene showed the least interaction. These theoretical results are in line with our experimental fluorescence spectroscopic data of LPC/1-anilino-8-napthalene sulfonic acid complex. Our present comprehensive investigation employing both theoretical and experimental methods provides a deeper understanding of graphene-lipid interaction, which holds paramount importance in the design and fabrication of graphene-based nanomaterials for biomedical applications. In this study, we employed the density functional theory-based methods to investigate the electronic and structural properties of graphene derivatives and LPC molecule using the Quantum Espresso package. The exchange-correlation functional was described within generalized gradient approximation (GGA) as parameterized by Perdew, Burke and Ernzerhof (PBE). The valence electrons were represented using plane wave basis sets. `The Grimme's dispersion method was used to include the van der Waals dispersion correction.

High-Throughput Computational Screening of Two-Dimensional Semiconductors

Two-dimensional (2D) materials have attracted great attention mainly due to their unique physical properties and ability to fulfill the demands of future nanoscale devices. By performing high-throughput first-principles calculations combined with a semiempirical van der Waals dispersion correction, we have screened 73 direct- and 183 indirect-gap 2D nonmagnetic semiconductors from nearly 1000 monolayers according to the criteria for thermodynamic, mechanical, dynamic, and thermal stabilities and conductivity type. We present the calculated lattice constants, formation energy, Young's modulus, Poisson's ratio, shear modulus, anisotropic effective mass, band structure, band gap, ionization energy, electron affinity, and simulated scanning tunnel microscopy for each candidate meeting our criteria. The resulting 2D semiconductor database (2DSdb) can be accessed via the Web site https://materialsdb.cn/2dsdb/index.html. The 2DSdb provides an ideal platform for computational modeling and design of new 2D semiconductors and heterostructures in photocatalysis, nanoscale devices, and other applications. Further, a linear fitting model was proposed to evaluate band gap, ionization energy, and electron affinity of 2D semiconductors from the density functional theory (DFT) calculated data as initial input. This model can be as precise as hybrid DFT but with much lower computational cost.

Ionic Dynamics and Vibrational Spectral Diffusion of a Protic Alkylammonium Ionic Salt through Intrinsic Cationic N-H Vibrational Probe from FPMD Simulations.

We employed density functional theory (DFT)-based molecular dynamics simulations to explore the structure, dynamics, and spectral properties of the protic ionic entity trimethylammonium chloride (TMACl). Structural investigations include calculating the site-site radial distribution functions (RDFs), the distribution of constituent cations and anions in three-dimensional space, and combined distribution functions of the hydrogen-bonded pair RDF versus angle, revealing the structural characteristics of the ionic solvation and the intermolecular interactions within ions. Further, we determined the instantaneous vibrational stretching frequencies of the intrinsic N-H stretch probe modes by applying the time-series wavelet method. The associated ionic dynamics within the protic ionic compound were investigated by calculating the time-evolution of the fluctuating frequencies and the frequency-time correlation functions (FFCFs). The time scale related to the local structural relaxation process and the average hydrogen bond lifetime, ion cage dynamics, and mean squared displacement were investigated. The faster decay component of the FFCFs, depicting the intermolecular motion of intact hydrogen bonds in TMACl, is 0.07 ps for the Perdew-Burke-Ernzerhof (PBE)-based simulation and 0.06 ps for the PBE-D2 representation. The slower time scale of the longer picosecond decay time component of PBE and PBE-D2 representations are 3.13 and 2.87 ps, respectively. These picosecond time scales represent more significant fluctuations of the hydrogen-bonding partners in the ionic entity and hydrogen-bond jump events accompanied by large angular jumps. The longest picosecond time scales represent structural relaxation, including large angular jumps and ion-pair dynamics. Also, ion cage lifetimes correlate with the slowest time scale of the associated dynamics of vibrational spectral diffusion despite the type of DFT functional. This study benchmarks DFT treatments of the exchange-correlation functional with and without the van der Waals (vdW) dispersion correction scheme. The inclusion of vdW interactions to the PBE functional represents a less structured state of the ionic entity and faster dynamics of the molecular motions relative to the one predicted by the PBE system. All the results illustrate the necessity of accurately describing the Coulomb interactions, vdW dispersive interactive forces, and localized hydrogen bonds required to sustain the energetic balance in this ionic salt.

Structures, Electronic Properties, and Gas Permeability of 3D Pillared Silicon Carbide Nanostructures.

Silicon carbide (SiC) is recognized as excellent material for high power/temperature applications with a wide-band gap semiconductor. With different structures at the nanosize scale, SiC nanomaterials offer outstanding mechanical, physical, and chemical properties leading to a variety of applications. In this work, new 3D pillared SiC nanostructures have been designed and investigated based on self-consistent charge density functional tight-binding (SCC-DFTB) including Van der Waals dispersion corrections. The structural and electronic properties of 3D pillared SiC nanostructures with effects of diameters and pillar lengths have been studied and compared with 3D pillared graphene nanostructures. The permeability of small gas molecules including H2O, CO2, N2, NO, O2, and NO2 have been demonstrated with different orientations into the 3D pillared SiC nanostructures. The promising candidate of 3D pillared SiC nanostructures for gas molecule separation application at room temperature is highlighted.

Copper-phthalocyanine (CuPc) and O, Li and Mn adatoms on graphene substrate: First-principles study of stability, magnetism and electronic properties

The effects of adatoms of Oxygen (O), Lithium (Li) and Manganese (Mn) on the adsorption properties of copper-phthalocyanine molecule on a graphene substrate have been investigated using the spin-polarized density functional theory (DFT) calculations. The effects of van der Waals dispersion correction of the type vdW-DF2 is also investigated. This work extends our earlier work (J.F. Matoko-Ngouma et. al., J. Mol. Struct., 1211 (2020) 128034) on molecular CuPc adsorption on a graphene substrate. Here, our structural models consist of CuPc having an adatom of X = Li, Mn and O at a stable site, i.e., X-CuPc, with the latter deposited on a graphene substrate in a configuration we have named X-CuPc/graphene. Also, we have considered structural models wherein CuPc is deposited on a X-decorated graphene, i.e., CuPc/X-graphene. Our results show that X-CuPc/graphene and CuPc/X-graphene structures are stable. In fact, we have found that the Li and Mn adatoms increase the binding of CuPc to the graphene substrate as evidenced by the increase in the adsorption energy of CuPc to graphene (CuPc/graphene) upon the aforementioned adatom adsorption. However, the Oxygen atom does not have significant effect on the relative stability of CuPc adsorption on graphene. Regarding the magnetization, incorporating O and Mn as an adatom in CuPc/graphene system enhance its magnetization while Li quenches the magnetization of CuPc when it is adsorbed with or without the graphene substrate. Our findings underline the possibility to improve molecular adsorption of phthalocyanine molecules on graphene and to manipulate its magnetization through the incorporation of external atoms such as Li, Mn and O. This may be consequential in the development of molecular electronics, spintronics and nanosensors.

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

Carbon and its analogous nanomaterials are beneficial for toxic gas sensors since they are used to increase the electrochemically active surface region and improve the transmission of electrons. The present article addresses a detailed investigation on the potential of the monolayer PC3 compound as a possible sensor material for environmentally toxic nitrogen-containing gases (NCGs), namely NH3, NO, and NO2. The entire work is carried out under the frameworks of density functional theory, ab-initio molecular dynamics simulations, and non-equilibrium Green's function approaches. The monolayer-gas interactions are studied with the van der Waals dispersion correction. The stability of pristine monolayer PC3 is confirmed through dynamical, mechanical, and thermal analyses. The mobility and relaxation time of 2D PC3 sensor material with NCGs are obtained in the range of 101–104 cm2 V−1 s−1 and 101–103 fs for armchair and zigzag directions, respectively. Out of six possible adsorption sites for toxic gases on the PC3 surface, the most prominent site is identified with the highest adsorption energy for all the NCGs. Considering the most stable configuration site of the NCGs, we have obtained relevant electronic properties by utilizing the band unfolding technique. The considerable adsorption energies are obtained for NO and NO2 compared to NH3. Although physisorption is observed for all the NCGs on the PC3 surface, NO2 is found to convert into NO and O at 5.05 ps (at 300 K) under molecular dynamics simulation. The maximum charge transfer (0.31e) and work function (5.17 eV) are observed for the NO2 gas molecule in the series. Along with the considerable adsorption energies for NO and NO2 gas molecules, their shorter recovery time (0.071 s and 0.037 s, respectively) from the PC3 surface also identifies 2D PC3 as a promising sensor material for those environmentally toxic gases. The experimental viability and actual implications for PC3 monolayer as NCGs sensor material are also confirmed by examining the humidity effect and transport properties with modeled sensor devices. The transport properties (I-V characteristics) reflect the significant sensitivity of PC3 monolayer toward NO and NO2 molecules. These results certainly confirm PC3 monolayer as a promising sensor material for NO and NO2 NCG molecules.

Designing nanoscale capacitors based on twin-graphene.

A 'twin-graphene' bilayer-based nanoscale capacitor and nanoscale dielectric capacitor are designed using a density functional theory approach including van der Waals dispersion correction. A strong effect on electronic properties is observed for different stacking modes. The AB stacking mode is the most stable one among the considered stacking modes with a band gap of 0.553 eV. Our predicted energy and charge-storage capacities are higher than those of other nanoscale capacitors designed using other two-dimensional carbon allotropes. We designed a nanoscale dielectric capacitor by placing a 'twin-graphene like BN sheet' (n = 1-3) sandwiched between 'twin-graphene' layers. The capacitance decreases significantly in the nanoscale dielectric capacitor model compared to the nanoscale capacitor model. However, the measured capacitance is higher than that of the previously studied nanoscale dielectric capacitor models. The significant capacitance of our proposed models ensures their promising applications for designing next-generation nanoscale capacitors.

Isocyanic acid (HNCO) dissociation on Rh(001) surface: A DFT study with and without dispersion correction

The adsorption and coadsorption of CO and NH species, and the dissociation of HNCO molecule on the flat Rh(001) surface have been investigated using density functional theory (DFT) with GGA-PBE functional. Also, effect of van der Waals (vdW) dispersion correction, in particular the vdW-DF-revPBE variant is studied. The hollow site on the Rh(001) surface is found to be the most energetically stable for NH, while the bridge site is found for the CO as well as HNCO molecule. However, the inclusion of dispersion correction to the PBE changes the order of site preference for the CO while NH site preference remains the same. Also, the inclusion of vdW-DF-revPBE correction reduces the adsorption energy. Furthermore, the Climbing-Image Nudged Elastic Band (CI-NEB) method has been used to determine the minimum energy path for the molecular HNCO dissociation into NH and CO on the Rh(001) surface. We obtain an activation energy of 0.55 eV for the standard PBE, whereas the inclusion of vdW-DF-revPBE dispersion to the PBE functional results in activation energy of 0.51 eV. Our study therefore suggests that the rapid reduction of nitrogen oxide (RAPRENOx), a chemical combustion process designed to remove harmful NO from harmful combustor exhaust, is a high temperature process, if the Rh(001) is used as a reaction surface. Our analysis of electronic structures, in the form of projected density of states and electronic density, unravels the origin of HNCO molecular dissociation on the flat Rh(001) surface.

Two-Dimensional Boron–Phosphorus Monolayer for Reversible NO2 Gas Sensing

We proposed a boron–phosphorus monolayer (BP-ML) and investigated its gas sensing properties by density functional theory including the van der Waals dispersion correction term. Electronic property...

Structural, magnetic and electronic properties of copper-phthalocyanine (CuPc) adsorbed on graphene: Ab initio studies

The energetics, electronic and magnetic properties of copper-phthalocyanine (CuPc) adsorbed on graphene have been studied, using the density-functional theory with variants of GGA and LDA as the exchange-correlation functionals. The effects of van der Waals (vdW) dispersion correction on the calculated properties are also investigated. Five different adsorption sites of CuPc on graphene have been considered. Our results shows that the vdW dispersion has significant effects on the final relaxed structure of the CuPc/graphene system and the CuPc adsorption process on graphene. As an illustration, we find that in the case of PBE functional, the graphene substrate remains almost flat after the CuPc adsorption whereas there is significant departure from graphene planar geometry when the vdW dispersion correction (i.e., PBE + vdW) is included. Also, with the PBE functional, the CuPc molecule adsorption process is that of physisorption whereas with the inclusion of vdW dispersion correction, the molecule is chemisorbed. However, for both the PBE functional and PBE + vdW dispersion correction, the CuPc molecule prefers to bind on the hollow site. Also, the energetically preferred CuPc adsorption site may depend on the CuPc concentration on graphene. Finally, we found that the CuPc/graphene nanocomposite acquires a magnetic moment of 1.0 μB. Our work highlights the influences of exchange-correlation functionals as well as vdW forces on the nature of interactions between an organic molecule and the graphene substrate.

UMBD: A Materials-Ready Dispersion Correction That Uniformly Treats Metallic, Ionic, and van der Waals Bonding

Materials design increasingly relies on first-principles calculations for screening important candidates and for understanding quantum mechanisms. Density functional theory (DFT) is by far the most popular first-principles approach due to its efficiency and accuracy. However, to accurately predict structures and thermodynamics, DFT must be paired with a van der Waals (vdW) dispersion correction. Therefore, such corrections have been the subject of intense scrutiny in recent years. Despite significant successes in organic molecules, no existing model can adequately cover the full range of common materials, from metals to ionic solids, hampering the applications of DFT for modern problems such as battery design. Here, we introduce a universally optimized vdW-corrected DFT method that demonstrates an unbiased reliability for predicting molecular, layered, ionic, metallic, and hybrid materials without incurring a large computational overhead. We use our method to accurately predict the intercalation potentials of layered electrode materials of a Li-ion battery system, a problem for which the existing state-of-the-art methods fail. Thus, we envisage broad use of our method in the design of chemo-physical processes of new materials.

Hydrogen evolution reaction electrocatalysis trends of confined gallium phosphide with substitutional defects

The integration of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) gives better prediction of the system properties towards the applications like water-splitting and gas storage capacity/mechanism. The pursuit of generating low-cost and effective catalyst for such purposes has motivated the material scientists and researchers to design and study the novel nanostructured materials both theoretically and experimentally. We have utilized the well-established state-of-the-art density functional theory (DFT) for envisaging the HER activity of the two-dimensionally confined Gallium Phosphide (GaP). The effect of substitutional defect caused by foreign atoms like boron and nitrogen on the structural, electronic and adsorption properties of the GaP nanowire is analyzed by incorporating the van der Waals dispersion correction. The energy differences and the contributions of the individual atomic species to the electronic energy states have been observed by computing the electronic density of states. Introduction of the defect in the system significantly modifies the electronic and adsorption properties of the system. The results suggest GaP to be highly active for hydrogen adsorption which further gets pronounced by introducing boron defect in the system. The results on adsorption energy and Gibbs free energy stipulating better adsorptive nature for hydrogen give confidence to utilize GaP as an HER catalyst by further tuning the adsorption response by means of defect engineering. In a nut-shell, we assert the dependence of material properties that are very sensitive to defects and the cause root beneath this response can serve as a blueprint for designing prominent materials for HER based applications.

Nitridation of the metallic Mo2C(001) surface from NH3 dissociative adsorption—A DFT study

Adsorption and sequential decomposition of ammonia on the metallic Mo2C(001) surface have been systematically computed using periodic density functional theory under the consideration of van der Waals dispersion correction (PBE-D3). It is found that NH3 adsorption prefers the top sites from low to saturation coverage. For the adsorption of surface NH2, bridge and hollow sites are possible at low coverage and only bridge sites are preferred at high coverage up to saturation. The adsorption of surface NH and N prefers the hollow sites. Sequential decomposition of NH3 into surface NH2, NH and N has low barrier and is highly exothermic. On the basis of surface Mo atoms, the saturation coverage of surface NH3, NH2, NH and N by using NH3 as nitridation agent is 0.75, 1.0, 1.0 and 0.5 monolayer, respectively. These results provide the basis for the study of surface properties and catalytic reaction of nitrided Mo2C surfaces. The dissociative adsorption of ammonia among others metals and molybdenum nitrides has been categorized and compared.

Mechanisms and Activity of 1‐Phenylethanol Dehydrogenation Catalyzed by Bifunctional NHC‐IrIII Complex

Acceptorless dehydrogenation of 1‐phenylethanol to acetophenone catalyzed by OH‐functionalized N‐heterocyclic carbene Cp*Ir(NHC) complexes under base‐free condition as well as under the promotion of protic co‐solvent tBuOH were investigated using density functional theory including solvation and van der Waals dispersion corrections. The first step is the 1‐phenylethanol dehydrogenation, which is more favored via an inner‐sphere over an outer‐sphere mechanism. The second step is H2 formation from Ir–H and O–H functionalities, which is the rate‐determining step, in agreement with the observed kinetic isotopic effect. The protic co‐solvent and 1‐phenylethanol act as a shuttle for proton transfer for the formation of H2.

Structural and electronic properties of bulk and ultrathin layers of V2O5 and MoO3

The structural and electronic properties of bulk and ultrathin films of V2O5 and MoO3 layered oxides have been studied with first-principles density functional theory calculations including Van der Waals dispersion corrections. The U parameter in the DFT + U approach has been determined in order to properly reproduce geometry, band-gap, macroscopic dielectric constant, and formation enthalpies of the two materials. The mono-, and multi-layers are cleaved along the 〈0 0 1〉 and 〈0 1 0〉 stable crystallographic orientations for V2O5 and MoO3, respectively. Three layers are needed in order to recover bulk-like properties of V2O5 and MoO3. Spin-orbit effects have been incorporated in our simulations, and they result in marginal effects (∼20–30 meV) on the electronic band-gap of V2O5 and a more pronounced (∼200 meV) effect on the band gap of bulk MoO3. We also discuss the importance of including local field effects for the reproduction of the anisotropy of the dielectric constant, which reflects the crystal structure of these materials.

Electronic and mechanical property of high electron mobility semiconductor Bi2O2Se

Using first-principles calculations combined with a semi-empirical van der Waals dispersion correction, we have investigated the structural, electronic and mechanical properties of Bi2O2Se. We predict that Bi2O2Se is a semiconductor with a band gap of 0.99 eV. By analyzing its bulk modulus, shear modulus, Young's modulus and Possion's ratio, we found that it is a ductile material. Furthermore, the shear anisotropic factors and the elastic anisotropy are also investigated. The minimum thermal conductivity of around 0.2 W/(m · K) and a Debye temperature of 18.23 K are determined by the theoretical elastic constants.

Local dynamics of copper active sites in zeolite catalysts for selective catalytic reduction of NOx with NH3

In Cu-zeolite based selective catalytic reduction of NOx with NH3 (NH3-SCR), Cu species (in particular CuI) solvated by NH3 molecules are predicted theoretically to be highly mobile with their mobility being decisive for the NH3-SCR reactivity at low temperatures (<250 °C). Direct experimental observation of the Cu mobility after NH3 solvation, however, has not been achieved yet. Here we show that complex impedance-based modulus spectroscopy, performed by following the corresponding dielectric relaxation processes at high frequencies (104 to 106 Hz), can be applied to monitor directly the dynamic local movement of Cu ions in zeolite catalysts under NH3-SCR related reaction conditions. Simultaneous in situ impedance and infrared spectroscopy studies, assisted by periodic DFT calculations with reliable van der Waals dispersion corrections, allowed us to identify the key factors determining the local dynamics of Cu ions in two representative Cu-zeolites, i.e. Cu-ZSM-5 and Cu-SAPO-34. The co-adsorption and interaction of NO and NH3 on CuII sites led to the formation of highly mobile CuI species and NH4+ intermediates, and, consequently, significantly enhanced local dynamics of Cu ions in both zeolite catalysts. The re-oxidation of CuI, which is the rate-determining step of NH3-SCR reaction, was more favorable in Cu-SAPO-34 than in Cu-ZSM-5, which can be attributed to the close coupling of NH4+ intermediate and Cu site promoting the formation of CuII-NO2/NH4+. As a result, the overall local dynamics of Cu, largely determined by CuI species, is less dependent on the NH4+ intermediate in Cu-SAPO-34 than in Cu-ZSM-5.

Structural, electronic, and dynamical properties of liquid water by ab initio molecular dynamics based on SCAN functional within the canonical ensemble

We perform ab initio molecular dynamics (AIMD) simulation of liquid water in the canonical ensemble at ambient conditions using the strongly constrained and appropriately normed (SCAN) meta-generalized-gradient approximation (GGA) functional approximation and carry out systematic comparisons with the results obtained from the GGA-level Perdew-Burke-Ernzerhof (PBE) functional and Tkatchenko-Scheffler van der Waals (vdW) dispersion correction inclusive PBE functional. We analyze various properties of liquid water including radial distribution functions, oxygen-oxygen-oxygen triplet angular distribution, tetrahedrality, hydrogen bonds, diffusion coefficients, ring statistics, density of states, band gaps, and dipole moments. We find that the SCAN functional is generally more accurate than the other two functionals for liquid water by not only capturing the intermediate-range vdW interactions but also mitigating the overly strong hydrogen bonds prescribed in PBE simulations. We also compare the results of SCAN-based AIMD simulations in the canonical and isothermal-isobaric ensembles. Our results suggest that SCAN provides a reliable description for most structural, electronic, and dynamical properties in liquid water.

Highly Sensitive Sensing of NO and NO2 Gases by Monolayer C3N

AbstractUsing density functional theory with van der Waals dispersion correction, the adsorption behavior of common gaseous pollutants (CO, NO, NO2, and NH3) on monolayer C3N is investigated. The adsorption sites and energies, binding distances, charge transfers, and electronic band structures are calculated to understand the influence of the adsorbed molecules on the transport properties of monolayer C3N. The current–voltage characteristics are calculated using the nonequilibrium Green's function formalism. It turns out that all investigated molecules are physisorbed on monolayer C3N and that NO and NO2 gases can be sensed with high sensitivity. The recovery time of the sensor is found to be outstanding in the case of NO sensing (2.4 μs at room temperature) and competitive to other materials in the case of NO2 sensing.