Transition Metal Adsorption Research Articles

5d transition-metal adsorption tailored valley splitting and magnetic anisotropy of Janus 2H-WSSe monolayer

Valley splitting and magnetic anisotropy of 5d TM (Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg) adsorbed Janus 2H-WSSe monolayers are investigated using first-principles calculations. The results show that 5d TM atoms adsorbed on the W-top site of Janus 2H-WSSe monolayer exhibit the lowest adsorption energy, regardless of the Se or S layer. The electronic states of Hf-SW and Re-SeW adsorbed systems cross the EF and show metallicity, while the other adsorbed systems still exhibit the semiconducting characteristics. According to the k·p model based on the effective Hamiltonian, the Zeeman effect arising from the local magnetic moment of 5d TM atoms lifts tunable valley splitting within 12.7-227meV owing to different SOC strength. A maximum valley splitting of 227meV is observed in the W adsorbed system, which is large enough to realize the valley Hall effect. Both perpendicular magnetic anisotropy (PMA) and in-plane magnetic anisotropy (IMA) can be adjusted by adsorbing different 5d TM atoms on the S/Se layer. Remarkably, the matrix elements differences (dx2–y2, dxy) decide the PMA and IMA behaviors, which are due to the competition of different TM-d orbitals based on the second-order perturbation theory. These results suggest that the 5d TM adsorbed Janus 2H-WSSe monolayer can be considered a good candidate for the spintronic and valleytronic devices.

Gas sensitivity research of transition metal (Fe, Zr, Ta, Tc) doped boron nitride nanosheets to indoor toxic gases (CH2O, NH3, Benzene): A DFT perspective

Indoor air quality affects human health, with CH2O, NH3 and Benzene being the three most common indoor toxic gases. In this work, we investigated the adsorption of transition metal (Fe, Zr, Ta, Tc) doped boron nitride nanosheets (BNNSs) for three indoor toxic gases based on density functional theory (DFT). Through a series of analyses after simulation, the results show that the adsorption of pristine BNNSs for the three toxic gases is low, whereas the adsorption of transition metal doped BNNSs for all the three gases are significantly enhanced. Among them, Ta-BNNSs is the structure with a large change in band gap after adsorption of CH2O and Benzene. For NH3, the band gap change after adsorption of Tc-BNNSs is the largest. We have analyzed the recovery time of these three adsorption systems at 298 K, 398 K and 498 K. The results showed that the recovery time of Ta-BNNSs for adsorption of CH2O or Benzene at all three temperatures was large, while the recovery time of Tc-BNNSs at 498 K was small. Thus Tc-BNNSs are a potentially recyclable NH3 sensor material. Finally, the relative adsorption energy analyses showed that Fe-BNNSs had large adsorption energies for all three toxic gases at room temperature and the desorption temperatures were all around 700 K. Therefore, Fe-BNNSs are promising as a recyclable adsorbent material for the three toxic gases.

Unraveling Hydrogen Adsorption on Transition Metal-Doped [Mo3S13]2- Clusters: Insights from Density Functional Theory Calculations.

Molecular and dissociative hydrogen adsorption of transition metal (TM)-doped [Mo3S13]2- atomic clusters were investigated using density functional theory calculations. The introduced TM dopants form stable bonds with S atoms, preserving the geometric structure. The S-TM-S bridging bond emerges as the most stable configuration. The preferred adsorption sites were found to be influenced by various factors, such as the relative electronegativity, coordination number, and charge of the TM atom. Notably, the presence of these TM atoms remarkably improved the hydrogen adsorption activity. The dissociation of a single hydrogen molecule on TM[Mo3S13]2- clusters (TM = Sc, Cr, Mn, Fe, Co, and Ni) is thermodynamically and kinetically favorable compared to their bare counterparts. The extent of favorability monotonically depends on the TM impurity, with a maximum activation barrier energy ranging from 0.62 to 1.58 eV, lower than that of the bare cluster (1.69 eV). Findings provide insights for experimental research on hydrogen adsorption using TM-doped molybdenum sulfide nanoclusters, with potential applications in the field of hydrogen energy.

Investigating the dilute magnetic semiconductor behavior of 4d transition metal adsorption on B4C3

We conducted a systematic investigation of B4C3 adsorbed with 4d-transition metals (4d-TMs), including Tc, Cd, Mo, Nb, Rh, Ru, and Ag, using first principles. This study involved an evaluation of structural, electronic, and magnetic properties. When single atom adsorption was adsorbed to B4C3 using elements such as Tc, Nb, Rh, Ru, and Ag, it demonstrated characteristics of a diluted magnetic semiconductor (DMS), manifesting magnetic moments. Conversely, Cd, Mo, and Pd exhibited behavior consistent with non-magnetic semiconductors. Ferromagnetic (FM) and antiferromagnetic (AFM) arrangements were formed through the adsorption of 2TM atoms on B4C3. In the FM setup, Ru and Nb uphold their roles as DMS. Interestingly, Tc and Rh exhibit half-metal behavior in this configuration, displaying their potential utility in spintronics applications. In the AFM configuration, Tc displayed half-metallic behavior, while the other metals maintained the same characteristics observed in the case of single TM adsorption. The reactivity of Nb-B4C3 is notably high owing to its low work function, whereas Cd-B4C3 is observed to be less reactive. AFM coupling is favorable in the 2Nb-, 2Rh-, and 2Ru-B4C3 systems, while 2Tc-B4C3 displays FM coupling. Transition metals belonging to the 4d series hold the potential to enhance the properties of B4C3, including its half-metallic, metallic, and semiconductor characteristics. These findings suggest the potential use of 4D transition metals adsorbed on B4C3 as a prospective material for spintronics and magnetic storage applications in the future.

Transition metal induced- magnetization and spin-polarisation in black arsenic phosphorous

The electronic and magnetic properties of two-dimensional black Arsenic Phosphorus (b-AsP) on adsorption of Transition Metals (TM) on its surface are investigated using density functional theory (DFT) based on first principles calculations. Spin-density of states (S-DOS) and the bandstructure of all the transition metals adsorbed structures have been plotted which reveals their change from non-magnetic to magnetic behaviour. The results suggest that pristine b-AsP which is a non-magnetic semiconductor turns into a half metal ferromagnet (HMF) on adsorption of Co, Fe and Ti, and it turns into a ferromagnet (FM) on adsorption of Cr and Zr. The total magnetic moments were also calculated to further support our results and findings. Strong magnetic moments were observed for Cr, Fe and Ti adsorbed b-AsP structures. Ag, Cu and Mo adsorption over b-AsP results into non-magnetic metallic characteristics with very weak magnetic moments. This transformation from a non-magnetic semiconductor to a magnetic HMF or FM material demonstrates the potential use of b-AsP in designing spin magnetic devices for various spin-based applications.

Potential applications of C2N-h2D/BN nanoribbon adsorption of transition metals in spintronic devices and magnetic storage devices

By splice C2N-h2D with BN, we construct a novel two-dimensional nanoribbon material. By doping Fe atoms, C2N-h2D/BN nanoribbons exhibit half-metallic properties, which is of great significance for their future applications in spintronic devices.

Modulating the ferromagnetism of Fe3GeTe2 with 3d transition metal adsorption and strain-engineering

Two-dimensional ferromagnetic materials hold great promise to develop energy-efficient magnetoelectric memory devices and next-generation spintronics. However, one of the crucial challenges for these materials is the realization of tunable magnetocrystalline anisotropy (MCA) to balance thermal stability and energy efficiency. Here, we systematically study the adsorption effects of 3d transition metals (3d-TMs) on the electronic structure and magnetic property of the Fe3GeTe2 (FGT) monolayer. The adsorption systems exhibit different ground state configurations depending on the adatoms, while the controlled perpendicular magnetic anisotropy has also been achieved. Notably, the Mn/FGT system can maintain the out-of-plane magnetic orientation with a changing amplitude of MCA energy up to 3.057 erg/cm2 as the external strain varies from −4% to 1%. In contrast, the Fe/FGT structure undergoes spin reorientation from in-plane to out-of-plan magnetization with a distinct modification behavior of MCA. We elucidate that the underlying atomistic mechanism mainly arises from the alteration of Fe-derived 3d-orbital states in response to the strain effect, leading to competitive changes in the different coupling states. These findings can not only provide useful guidance to optimize two-dimensional magnets for fundamental research but also reveal the promising potential of TMs/FGT materials for the development of ultra-low energy spintronic devices.

Density functional theory of NO2 and N2O adsorption on the transition metal modified TiO2 surface

The geometric structure and electronic properties of transition metal M (M = Cu, Fe, Mn)-TiO2 (101) surface adsorbed by NO2 and N2O were calculated by density functional theory (DFT) and DFT + U theory. Eight models were established to explore the effect of NO2 and N2O adsorption, and the results show that transition metal adsorption has different effects on the redox reaction of NO2 and N2O. From the stability of adsorption structure, the adsorption of NO2/N2O on Mn atom is more stable, and the adsorption of N2O on Fe atom is more stable than that of NO2. The analysis of charge transfer and electronic structure show that a large number of free active electrons are formed around the Mn and Fe atoms, which are connected with the N atoms of NO2/N2O, and one N atom in N2O changes from losing electrons to gaining a small number of electrons. This means that the Mn and Fe atoms can stimulate more active electrons to exchange with NO2 and N2O, that is, they can exchange more electrons with NO2/N2O before selective catalytic reduction (SCR) reaction, which is beneficial to the succeeding catalytic reaction.

Effects of transition metal dopants and Se-vacancy defects on carbon monoxide sensitivity of WSe2/graphene heterostructures

In this study, we performed first principles calculations to explore the adsorption behavior, electronic structures, and magnetic properties of CO molecules on pristine transition metal (TM)-doped WSe2/graphene (WSe2/G) heterostructures with vacancy defects. Introducing the Se-vacancies and TM dopants (Ti, Cr, Ni, and Co) enhanced the adsorption stability of CO on WSe2/G. The adsorption mechanism of CO molecules on primordial WSe2/G was physisorption, with large interaction distances and small adsorption energies. However, when the CO molecules were adsorbed on the defected and TM-doped WSe2/G, the adsorption mechanism changed to chemisorption. The adsorption of TMs (Ti, Cr, Ni, and Co) on the WSe2/G heterostructures was systematically investigated to evaluate its potential for application in gas sensor devices. The recovery time of CO@Cr–WSe2/G after CO adsorption was suitable for CO detection gas sensors. The findings of our study provide new technical directions for developing CO gas sensor devices.

Transition-metal single atom anchored boron-graphdiyne and its adsorption behavior to CO, NO, HCHO toxic gases

Layer materials anchored with transition-metal (TM) single atom is a typical catalyst model for many applications. Recent studies reveal that boron-graphdiyne (BGDY) has unique properties similar to grephyne e.g. two-dimensional nature, excellent electrical conductivity, and good thermal–mechanical properties. More importantly, it possesses electron-deficient boron atoms, larger molecular pore and more π bonds. These advantages motivate us to investigate TM single atom anchored BGDY and its adsorption behavior to CO, NO and HCHO. The DFT calculations reveal that BGDY can accommodate TMs at multiple sites and the favorite adsorption site is near the highly active C≡C-B-C≡C corner. The TMs adsorption is stronger than that on graphene. Overall, the adsorption energies, height and structural distortion vary regularly as moving along a d series. These phenomena are closely related to electrons exchange and TMs characteristic. The TMs of oxidation on BGDY can effectively adsorb CO, NO and HCHO. Interesting electron exchange occurs among gas, TMB/TM and the adjacent C atoms in GDY substrate. The three atom groups work synergistically which suggests tunable electron environment. The adsorption results reveal that TMs adsorption endows BGDY layer beneficial properties, and TMs-BGDY have good potential as the detection or fixation materials for CO, NO and HCHO.

Density functional theory study of NO adsorption on the transition metal M (M=Cu, Fe and Mn) modified TiO2 surface

To study the effect of different kinds of transition metals and their proportions on NO adsorption on TiO2 surface, the density functional theory (DFT) method was used to calculate the energetic, geometric structure and electronic structure of the adsorption of NO on transition metal M (M = Cu, Fe and Mn)-anatase TiO2 (101) surface. The above transition metals were adsorbed on anatase TiO2 (101) surface in three different adsorption ratios, which are single transition metal adsorption model, mixed 2:2 and 1:3 ratio models. On the basis of the study, 13 models were established to study the effects of transition metals and adsorption ratio on NO oxidation to determine the optimal adsorption model. It has been found from the energetic calculations that mixed adsorption model is more stable for the adsorption of NO. The results of electronic structure and charge distribution analysis showed that a large quantity of active electron clusters are distributed around Mn and Fe atoms, which are attached to a large area of N atoms in NO, indicating that Mn and Fe can provide more electrons for catalytic reaction and facilitate electron exchange between catalyst and NO. Among all the adsorption models, the 3Fe+1Mn–TiO2 and 3Mn+1Fe–TiO2 models are superior, i.e., they can exchange more electrons with NO before the catalytic reaction, which is conducive to the subsequent catalytic reaction.

Spiderweb-inspired fabrication of 3D MXene hybrid filler with multilayer and multiscale features for multifunctional polydimethylsiloxane composites

Polymer-based composite with high thermal conductivity and excellent fire safety is urgently desired and required in the field of thermal management of advanced electronic devices. In this study, inspired by the structure of a spiderweb, we reported a polymer composite with three-dimensional (3D) interconnected spiderweb-like structures by assembling adsorption of transition metal carbides/nitrides (MXene) and diethylenetriaminepenta(methylene-phosphonic acid) coordinated cobalt ions complex. In this composite, MXene combined with the coordination complex forms a 3D network structure with multi-layer/-scale features, which enables high cross-plane thermal conductivity (∼0.59 K w-1m−1) and excellent flame retardancy, especially including effective inhibition of toxic CO and asphyxiating CO2 production. Notably, the 3D MXene networks embedded in the polymer matrix impart the composite with an intelligent damage detection function that is able to detect the depth of cracks. This bioinspired strategy provides a promising approach to creating high-performance polymer-based composites.

Influence of vacancy and adsorption of transition metal on performance of single layer of boron pnictides as a supercapacitor electrode: An ab initio investigation

Our work employs density functional theory (DFT), exploring the potential of transition metal adsorption (3d, 4d, and 5d) on boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb) as a means of increasing energy storage capacity for supercapacitor electrodes. We observe band gaps of 4.56 eV, 0.97 eV, 0.80 eV, and 0.51 eV for BN, BP, BAs, and BSb, respectively. The pristine BX (X = N, P, As, Sb) monolayers have a maximum quantum capacitance (CQ-max) of 17.15 μF/cm2, 33.52 μF/cm2, 36.91 μF/cm2, and 52.53 μF/cm2. With the adsorption of transition metals, the band gaps decrease due to the additional occupied states, leading to an increase in density near the Fermi region and a higher CQ-max of 146.54 μF/cm2, 132.95 μF/cm2, 121.43 μF/cm2, and 111.76 μF/cm2 for BN, BP, BAs, and BSb when adsorbed on the center of the hexagonal. Upon adsorption of transition metals on the Boron atom, the CQ-max values increase to 137.51 μF/cm2, 210.17 μF/cm2, 190.36 μF/cm2, and 169.79 μF/cm2 for BN, BP, BAs, and BSb, respectively. We also examine mono-vacancies of boron and X atoms (X = N, P, As, Sb) to further explore the potential of these materials for energy storage applications.

Adsorption of 4D and 5D transition metals on antimonene for optoelectronics and spintronics applications

For spintronic devices, the adsorption of transition metal (TM) atoms may provide two-dimensional (2D) materials with enhanced electrical and magnetic characteristics. Herein, the stability, electronic, and magnetic properties of 4d (Ag, Cd) and 5d (Ir, Pt, Au, Hg) TM adsorbed mono-layer antimonene (Sb) are investigated thoroughly using first-principles calculations. We find out the stability and suitability of the material by using different parameters like relative formation energy, thermal stability, and phonon dispersion curve. The adsorption energies suggest that the most favorable position of adsorption is the hollow (H) site where the ground state energy is lowest. In the case of Ir, and Au adsorbed Sb, the metallic and magnetic behavior is observed due to the change of spin-up and down. Adsorption of Ag also reveals metallic behavior but there is symmetry in high and low spin and shows non-magnetic results. Interestingly, the spin-polarized semiconducting state appears in Cd, Pt, and Hg adsorbed Sb and shows non-magnetic semiconductor behavior. Our study reveals that the TMs adsorbed Sb can be used in potential applications like spintronics, magnetic storage devices, optoelectronics, and Nanoelectronics applications.

Effect of transition metal modification on the sensing characteristics of arsenene adsorption of nitrogenous toxic gases

Detection and control of toxic gas molecules are becoming more and more indispensable. In this paper, the electronic properties of primary and adsorbed transition metal (TM) atoms (Mo, Ni, Pd, Ti and Zr) arsenene with the adsorption of toxic nitrogenous gas molecules (NH3, NO and NO2) by using first-principles methods. The calculated results show that the adsorption of transition metal atoms significantly enhances the interaction between gas molecules and the substrate. In particular, the arsenene with Ti or Zr adsorbed has the best adsorption energy and the most charge transfer from the substract to gas molecules. Most of the systems retain their semiconductor properties, expect for the Zr-Arsenene with nitric oxide adsorbed, which have unique metallic properties. Interestingly, the system with NO and NO2 adsorbing can induce the magnetism. At the same time, uniaxial strain can change the adsorption strength of the system, and adjust the NO2 sensing characteristics of arsenene. It is hoped that the arsenene with transition metal adsorbed is a potential candidate for the detection of nitrogen-containing toxic gas molecules.

The effective regulation of heterogeneous N-heterocyclic carbenes: structures, electronic properties and transition metal adsorption.

Heterogeneous N-heterocyclic carbene materials have attracted increasing interest in the fields of materials science and catalysis due to their unique properties and potential applications. However, current heterogeneous systems primarily focus on a single class of carbene. In this work, we simultaneously introduce two classes of typical five-membered carbenes into a graphene lattice, forming a series of novel two-dimensional heterogeneous N-heterocyclic carbene nanomaterials (2D-NCMs) composed of multiple carbenes. First-principles calculations demonstrate the thermodynamic stability of the designed 2D-NCMs, as well as their diverse electronic properties ranging from metallic to semiconducting. The incorporation of carbenes in the 2D-NCMs enables them to adsorb both acidic BCl3 and basic CO molecules, thus exhibiting unique amphoteric properties. Furthermore, the 2D-NCMs exhibit remarkable adsorption capacities for ten transition metals, highlighting their promising potential for future catalytic applications. By adjusting the proportions of the two classes of carbenes, we can effectively regulate the electronic properties and adsorption capacities of small molecules and transition metals in the 2D-NCMs. This study presents a novel strategy for designing and regulating the properties of heterogeneous N-heterocyclic carbenes, offering significant implications in the fields of catalysis and materials science.

Optoelectronic and magnetic properties of transition metals-adsorbed GeC monolayer

The optoelectronic and magnetic behaviors of GeC monolayer after transition metals (TMs) adsorption have been systematically discussed using density functional theory. The calculated data illustrates that the optimal adsorption sites of Sc-, Ti-, V-, Cr-, Mn-, Fe-, and Co-GeC systems are all located at [Formula: see text] site, while the Ni- and Cu-GeC systems are situated in [Formula: see text] site. The band structures of Ti-, Fe-, and Ni-GeC systems still remain nonmagnetic semiconductors, while the Sc-, Cr-, and Cu-GeC systems exhibit magnetic semiconductor behaviors, and the band gaps are 0.11 eV (Sc), 0.30 eV (Cr), and 0.57 eV (Cu), respectively. In particular, V- and Mn-GeC systems exhibit half-metallic characteristics, and Co-GeC system exhibits magnetic metal characteristics. And the magnetic moments of Sc-, V-, Cr-, Mn-, Co-, and Cu-GeC structures have been obtained to be 0.08, 1.00, 2.00, 1.00, 0.04, and 1.00 [Formula: see text], respectively. Furthermore, the charge transfer was exhibited between the GeC and TM. Especially, the work function of GeC can decrease greatly after TM adsorption, among them, the work function of Sc-GeC is 37.9% lower than that of GeC. Consequently, it indicates the usefulness of the TM-GeC system for the fabrication of spintronic and nanoelectronic devices.

Removing Non-Biodegradable Toxic Ions via Bio-Oxidation Analysis in Anzali Lagoon: A Usage of Seaweed in Biodiversity

Seaweed has been considered a treatment with the possibility of saving the environment in Anzali Lagoon in Iran due to its eco-potential, accessibility, and anti-toxic metal ion. Mostly, transition metals are toxic to human organs. Due to these problems and concerns, this study exhibits suitable adsorption materials for several native materials. Using the seaweeds of Anzali Lagoon in Iran for treatment has shown prominent results compared with other materials. The adsorption of transition metals by dead seaweed biomass offers a comparative advantage over other natural adsorption materials. This work describes the situation of heavy metals on the environment and why dead seaweed biomass is considered for remediation, among other materials. This work provides general ways to remove dissolved metals and toxic ions from Anzali Lagoon. Each of the various stages of operations of this lagoon will be discussed with their role in the metals removal process. The described treatment is general for metals and ion oxides removal. Some variations will exist among different systems. In layman's terms, these methods are intended to provide a suitable understanding of the precipitation process for toxic water treatment application. This investigation also provides a general method on how to remove dissolved metals (third and fourth-row elements of Mendeleyev tables) from toxic waters for discharge into sanitary systems.

Identifying Key Descriptors for the Single-Atom Catalyzed CO Oxidation

Identifying Key Descriptors for the Single-Atom Catalyzed CO Oxidation

Enhancing the optical absorption of Ga2SeTe Janus monolayer by adsorption of transition metals

Enhancing the optical absorption of Ga2SeTe Janus monolayer by adsorption of transition metals