Termolecular Eley-Rideal Research Articles

A single Mn atom supported by a boron-vacancy in a BN monolayer: An encouraging catalyst for CO oxidation

Single-atom catalysts (SACs) are known for their exceptional activity, primarily attributed to the abundance of low-coordinated metal atoms, which enable efficient activation of robust chemical bonds, including CO bonds. In this work, we explore the prospective utilization of a specific SAC, isolated Mn atoms supported on Boron nitrogen (Mn/BN), for CO oxidation. By analyzing the adsorption/co-adsorption energies of CO, O2, O2+CO, and 2CO, we create a set of screening criteria and conduct a comparative analysis of the chemical processes involved in CO oxidation. The Langmuir-Hinshelwood (LH), Eley-Rideal (ER), termolecular Langmuir-Hinshelwood (TLH) and termolecular Eley-Rideal (TER) mechanisms are investigated. Results indicate the ER and LH mechanisms feature pronouncedly lower barrier of 0.33 and 0.41 eV, respectively, for the rate-limiting step, than those of the TLH (0.72 eV) and TER (3.00 eV) mechanisms, suggesting that the ER and LH mechanisms are favorable at normal temperature. This study offers valuable insights that can inform future developments in the design of low-temperature CO oxidation processes utilizing SACs.

Termolecular Eley–Rideal pathway for catalytic oxidation of nitric oxide on [Pt2]0,± dimers using O2

AbstractA comprehensive density functional theory (DFT) investigation of the catalytic oxidation of NO to NO2 on neutral and charged [Pt2]0,± dimers has been considered employing M06L/def2TZVP level of theory. Single as well as co‐adsorption energies of NO and O2 molecules suggest that the traditional Langmuir Hinshelwood (LH) mechanism and less explored termolecular Eley–Rideal (TER) and termolecular Langmuir Hinshelwood (TLH) mechanisms, are suitable for a full catalytic reaction pathway in which two NO molecules are converted to two NO2 molecules, initiated by an activated O2 molecule. Activation barrier reveals that the TER mechanism is found to be more reliable in converting two NO molecules into two NO2 molecules on [Pt2]¯ dimer. In addition to shedding light on the intrinsic characteristics of Pt2 dimers, the study will serve as a benchmark for investigating the oxidation process of NO to NO2 utilizing models of termolecular chemical processes.

Heterogeneous Co1/P1Mo12O40 single-atom catalyst for CO oxidation via termolecular Eley-Rideal (TER) mechanism

Catalytic mechanisms, micro-kinetic and thermodynamics studies of Phosphomolybdic acid (PMA) supported non-noble metal (NNM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, and Zn1) single-atom catalysts (SACs) are explored for carbon monoxide (CO) oxidation by using DFT calculations. The results reveal that Co1/P1Mo12O40 have demonstrated excellent ability to adsorb (CO, O2) molecules, resulting in significant charge transfer from the catalyst surface to the adsorbate, which is essential to produce CO2 under normal reaction conditions. The various reaction pathways, including Eley Rideal (ER), Langmuir Hinshelwood (LH), Termolecular Eley Rideal (TER), and Mars Van Krevelen (MvK) are explored for CO oxidation on Co1/P1Mo12O40 to authenticate the most auspicious reaction mechanism. The energy barrier for the TER mechanism was 0.41 eV, lower as compared to the other reported materials which suggests that the Co1/P1Mo12O40 SACs would be the most appropriate future material for CO oxidation. To further validate the results, we performed the microkinetic investigation which predicts the CO oxidation rate of 4.58 × 106 s − 1. The key role of spin-magnetic moment for the promotion of CO oxidation by using Co1 single-atom catalyst was revealed from the deep electronic analysis. The current results would provide appreciated guidelines for experimentalists to develop less expensive and more effective non-noble metal SACs for CO oxidation.

Theoretical study on the reaction kinetics of CO oxidation by nitrogen-doped graphene catalysts with different ligand structures

Harmful carbon monoxide (CO) gas from vehicle exhaust and fossil fuel combustion seriously affects the ecological environment and human health, although this issue can be effectively solved by low-temperature catalytic combustion. Herein, an Fe and N codoped double vacancy graphene catalyst (Fe-CxNy) for the low-temperature catalytic combustion of CO is proposed, and the mechanism of the CO catalytic combustion reaction over the catalyst is systematically investigated by using density function theory (DFT). Four oxidation mechanisms, including Eley–Rideal (ER1 and ER2), Langmuir-Hinshelwood (LH) and Termolecular Eley–Rideal (TER), were compared in terms of oxidation pathways and energy distribution. All the results indicate that Fe-CxNy catalysts have efficient catalytic activity. The Fe-CN3 catalyst with the predominant LH reaction mechanism showed the best performance for the catalytic combustion of CO with only 0.20 eV, which was comparable to that of noble metals. The rate constant calculations further demonstrate that Fe-CN3 exhibits excellent catalytic performance at low temperatures. This work not only provides a theoretical basis for the design and development of low-temperature catalytic combustion CO catalysts, but also provides data support for the kinetic model of CO combustion reaction.

A theoretical investigation of NO oxidation using single metal atom catalysts with boron nitride

The principal pollutant, nonstop emitted, is nitric oxide (NO), organized with a small amount of nitrogen dioxide (NO2). A significant technology for their removal is their reaction with ammonia via choosy catalytic reduction with the momentous bottleneck for held catalysts being the high temperature vital for the catalytic activity (200–400 °C). Using first-principles theoretical approaches, the catalytic processes and bonding analyses of NO oxidation over transition metal (SAC) scattered on the boron nitride (BN) surface have been comprehensively examined. For isolated TM atom catalysts, BN is a good support. O2@TM-BN, NO@TM-BN, ON@TM-BN, 2NO@TM-BN, 2O2@TM-BN, and NO + O2@TM-BN configurations and the binding energies were calculated. In comparison to the other TM-SACs, V-/Cr-BN was originate to be the most gifted SAC for NO oxidation. It was discovered that at ambient temperatures, V-/Cr-BN SAC is precise volatile for NO oxidation, with squat stimulation barriers to the rate-determining stages for (V and Cr) Eley Rideal (0.25, 0.02, 0.12, and 0.19 eV), Langmuir Hinshelwood (0.73 and 0.55 eV), and Termolecular Eley-Rideal (0.41 and 0.30 eV) mechanisms. A comparative analysis of the results revealed that Cr-BN NO oxidation is additional auspicious than V-BN NO oxidation. These discoveries offer important insights into the development of exceedingly capable and selective dissimilar SACs for NO oxidation with TMs.

A density functional theory study of the CO oxidation on Pt1 supported on PtX2 (X = S, Se, Te)

The geometric stability, electronic structure and catalytic properties towards CO oxidation of a single Pt atom supported on PtS2, PtSe2, PtTe2 with a S, Se, and Te vacancies (Pt1/PtX2) were systematically explored by density functional theory calculations. The results showed that the single Pt atom can be located at the vacancy site stably, providing accessible active sites for CO oxidation. Both the Langmuir-Hinshelwood (LH) mechanism and the termolecular Eley-Rideal (TER) mechanism were considered comprehensively. By comparing the rate-determining step (RDS) of CO oxidation process, we found that the LH mechanism is easier to achieve. Meanwhile, as the X atom changes from S to Te, the RDS energy barrier gradually decreases, which is attributed to promoted adsorption and activation of O2 molecules on Pt1/PtX2. The results show that Pt1/PtTe2 is the most active catalysts with a low RDS barrier of 0.41 eV. This work provides an important reference for the design of single atom catalysts (SACs) based on transition metal dichalcogenides (TMDs), and has profound implications for the use of supported SACs on defective TMDs for CO oxidation or other reactions.

Simultaneous catalytic oxidation mechanism of NO and Hg0 over single-atom iron catalyst

Among the many pollutants emitted from coal-fired power plants, elemental mercury (Hg0) and nitrogen oxides (NOx) are widely concerned and regarded as a global environmental problem. Catalytic oxidation is an effective method to remove the above power plant pollutants. Although the recent pioneering experiment found that single-atom catalysts (SACs) exhibit excellent performance for the oxidation of NO and Hg0, the reaction mechanism for the simultaneous removal of NO and Hg0 has not been thoroughly revealed. In this work, a single-atom iron catalyst supported by a double vacancy doped graphene substrate with four N atoms (Fe1N4) was used to explore the reaction mechanism of O2 simultaneous catalytic of NO and Hg0. By using DFT method and energy span model, all possible paths of simultaneous catalytic oxidation of NO and Hg0 are enumerated. Among the ten paths we found, Termolecular Eley-Rideal (TER) mechanism has the lowest energy barrier. The rate determining reaction barrier is 1.59 eV. Disregarding the contribution of molecular collisions, TER path is more kinetically favorable for the integrated removal of NO and Hg0. Comprehensive consideration of intermolecular collisions, the catalytic oxidation reaction follows the E-R mechanism. The study deepened the understanding of the reaction mechanism of simultaneous removal of NO and Hg0.

Theoretical investigation of CO oxidation by single cobalt atom within two-dimensional porphyrin sheet

In this paper, the oxidation mechanism of carbon monoxide (CO) on two-dimensional porphyrin sheet within a single cobalt atom (Co-TDPs) was studied by density functional theory with dispersion (DFT-D). The stability of Co-TDPs at different temperatures was verified by first-principle molecular dynamics simulations. Absorption energies of reactant and product to anchor to the Co–N4 site showed CO and O2 adsorption to be stronger than the CO2 adsorption. In addition, the Langmuir–Hinshelwood, Eley–Rideal (ER), and ter-molecular Eley–Rideal (TER) mechanisms were used to investigate the reaction mechanisms of CO oxidation on Co-TDPs. The Langmuir–Hinshelwood (LH) and ER mechanisms were feasible reaction profiles of CO oxidation because of their smaller energy barrier. The results suggested that the Co-TDPS was acting as a catalyst for CO oxidation in the mild condition.

Termolecular Eley–Rideal pathway for efficient CO oxidation on phosphorene‐supported single‐atom cobalt catalyst

AbstractDensity functional theory calculations are conducted to examine the oxidation of CO on a single Co atom anchored on a two‐dimensional phosphorene monolayer (Co@Pn). The stability of the Co adatom on the Pn monolayer was revealed by ab initio molecular dynamics simulations. Three plausible pathways for CO oxidation over Co@Pn were explored: Langmuir–Hinshelwood (LH), Eley–Rideal (ER), and the recently proposed termolecular Eley–Rideal (TER) mechanisms. The TER pathway has a relatively lower energy barrier for the rate‐determining step (0.55) than those of the LH (0.81) and ER (0.70 eV) pathways. The efficiency of TER pathway can be interpreted by CO‐promoted O2 activation via the effective formation of a five‐membered ring composed of two CO and one O2 molecules. The results open a new avenue for developing phosphorene‐supported non‐noble transition metal single‐atom catalysts for various catalytic applications.

Non-noble metal single-atom catalyst with MXene support: Fe1/Ti2CO2 for CO oxidation

MXenes have attracted considerable attention owing to their versatile and excellent physicochemical properties. Especially, they have potential applications as robust support for single atom catalysts. Here, quantum chemical studies with density functional theory are carried out to systematically investigate the geometries, stability, electronic properties of oxygen functionalized Ti 2 C (Ti 2 CO 2 ) supported single-atom catalysts M 1 /Ti 2 CO 2 (M = Fe, Co, Ni, Cu Ru, Rh, Pd, Ag Os, Ir, Pt, Au). A new non-noble metal SAC Fe 1 /Ti 2 CO 2 has been found to show excellent catalytic performance for low-temperature CO oxidation after screening the group 8-11 transition metals. We find that O 2 and CO adsorption on Fe 1 atom of Fe 1 /Ti 2 CO 2 is favorable. Accordingly, five possible mechanisms for CO oxidation on this catalyst are evaluated, including Eley-Rideal, Langmuir-Hinshelwood, Mars–van Krevelen, Termolecular Eley-Rideal, and Termolecular Langmuir-Hinshelwood (TLH) mechanisms. Based on the calculated reaction energies for different pathways, Fe 1 /Ti 2 CO 2 shows excellent kinetics for CO oxidation via TLH mechanism, with distinct low-energy barrier (0.20 eV) for the rate-determining step. These results demonstrate that Fe 1 /Ti 2 CO 2 MXene is highly promising 2D materials for building robust non-noble metal catalysts. MXene supported non-noble metal single-atom catalyst Fe 1 /Ti 2 CO 2 is found to exhibit excellent activity for low-temperature CO oxidation through first-principles computational modelling.

CO oxidation on MXene (Mo2CS2) supported single-atom catalyst: A termolecular Eley-Rideal mechanism

Finding transition metal catalysts for effective catalytic conversion of CO to CO2 has attracted much attention. MXene as a new 2D layered material of early transition metal carbides, nitrides, and carbo-nitrides is a robust support for achoring metal atoms. In this study, the electronic structure, geometries, thermodynamic stability, and catalytic activity of MXene (Mo2CS2) supported single noble metal atoms (NM = Ru, Rh, Pd, Ir, Pt and Au) have been systematically examined using first-principles calculations and ab initio molecular dynamic (AIMD) simulations. First, AIMD simulations and phonon spectra demonstrate the dynamic and thermal stabilities of Mo2CS2 monolayer. Three likely reaction pathways, Langmuir-Hinshelwood (LH), Eley-Rideal (ER), and Termolecular Eley–Rideal (TER) for CO oxidation on the Ru1- and Ir1@Mo2CS2 SACs, have been studied in detail. It is found that CO oxidation mainly proceeds via the TER mechanism under mild reaction conditions. The corresponding rate-determining steps are the dissociation of the intermediate (OCO-Ru1-OCO) and formation of OCO-Ir1-OCO intermediate. The downshift d-band center of Ru1- and Ir1@Mo2CS2 help to enhance activity and improve catalytst stability. Moreover, a microkinetic study predicts a maximum CO oxidation rate of 4.01 × 102 s-1 and 4.15 × 103 s-1 (298.15 K) following the TER pathway for the Ru1- and Ir1@Mo2CS2 catalysts, respectively. This work provides guideline for fabricating and designing highly efficient SACs with superb catalyts using MXene materials.

Theoretical insights into the CO/NO oxidation mechanisms on single-atom catalysts anchored H4,4,4-graphyne and H4,4,4-graphyne/graphene sheets

Novel two-dimensional (2D) carbon-based substrates supported single-atom catalysts (SACs) have gained enormous interests. Herein, the adsorption property of single transition metal (TM) catalysts anchored at H4,4,4-graphyne (TM-H4,4,4-GY) are investigated using the first-principle calculations. The graphene substrate can provide the electron transfer to H4,4,4-GY and then improve the stability of TM atoms on H4,4,4-GY sheet (TM-H4,4,4-GY/G). Different kinds of TM adatoms and gas reactants can effectively control the electronic and magnetic properties of Mn-H4,4,4-GY and Mn-H4,4,4-GY/G systems. Four catalytic mechanisms for NO and CO oxidations are comparably analyzed via Langmuir-Hinshelwood (LH), Eley-Rideal (ER), new ER (NER) and termolecular ER (TER) reactions. The calculated results reveal that the NO and CO oxidation processes exhibit various reaction rates on different substrates. Compared with NO oxidation on Mn-H4,4,4-GY surface, the ER and LH mechanisms as the starting state for CO oxidation are energetically more favorable than other ones. On the Mn-H4,4,4-GY/G sheet, the CO oxidation processes by ER and NER mechanisms have relatively smaller energy barriers and exhibit higher reaction rates than those of NO oxidation. Therefore, the oxidation reactions of CO acts as a leading role in the first stage and the NO oxidation may happen in the second stage. These results provide an effective descriptor about geometric structure, electronic, magnetic, gas sensoring and catalytic properties of novel 2D carbon-based catalysts.

Co Anchored B36 Cluster as a Novel Single Atom Catalyst for Removing Toxic CO Molecules: A Mechanistic First‐Principles Study

AbstractThe catalytic oxidation of toxic carbon monoxide (CO) into carbon dioxide (CO2) is one of the most significant reactions in heterogeneous catalysis and industrial chemistry. Hence, finding efficient and cost‐effective catalysts for CO oxidation is very critical. In this study, the electronic and catalytic properties of a Co atom incorporated B36 cluster (Co@B36) are investigated by means of first‐principles calculations. The results show that the Co atom can seriously tune the properties of the B36 cluster due to significant hybridization between the 3d states of the Co atom and the B‐2p states of the surrounding B atoms. This induces a significant positive charge on the Co atom, providing an active site for O2 and CO molecules to attack. Furthermore, the well‐known mechanisms for CO oxidation, namely the Eley‐Rideal (ER), Langmuir‐Hinshelwood (LH), termolecular Eley‐Rideal (TER), and new Eley‐Rideal (NER), are taken into account in this work. According to our findings, the LH and TER mechanisms are the most energetically efficient routes for CO oxidation; however, the favored mechanism may be depending on the relative concentrations of CO and O2 molecules in the reaction mixture. The obtained activation energies through the TER and LH mechanisms are also comparable with those reported on noble metals. The findings of this work might help in the design and manufacture of noble‐metal free single atom catalysts for the removal of harmful CO molecules from the environment.

Catalytic role of B atoms in CO oxidation on B-doped graphene

We have performed periodic first-principles calculations to examine the catalytic activity of B-doped graphene in oxidation of CO to CO2. It is found that B atoms of B-doped graphene can provide active sites to adsorb CO and O2 molecules. Based on our results, the termolecular Eley-Rideal (TER) pathway is the most energetically relevant mechanism for the CO + O2 reaction. Compared with the single noble-metal catalysts, B-doped graphene exhibits exceptional catalytic performance to oxidize CO molecules at normal temperatures. The findings can provide guidelines for designing active metal-free catalysts by doping of graphene.

Cobalt anchored CN sheet boosts the performance of electrochemical CO oxidation* *Project supported by the National Natural Science Foundation of China (Grant Nos. 11574167 and 11874033).

Single-atom catalysts (SACs) have attracted great interest due to their significant roles played in applications of environmental protection, energy conversion, energy storage, and so on. Using first-principles calculations with dispersion-correction, we investigated the structural stability and catalytic activity of Co implanted CN sheet towards CO oxidation. The adsorption energy of CO and O2 on the catalysts Co@CN and 2Co@CN are close, thus preventing CO poisoning. Among three possible CO oxidation mechanisms, termolecular Eley-Rideal is the most appropriate reaction path, and the corresponding rate-limiting reaction barriers of the two systems are 0.42 eV and 0.38 eV, respectively.

Atomic level N-coordinated Fe dual-metal embedded in graphene: An efficient double atoms catalyst for CO oxidation

Double atoms catalysts (DACs) emerged very recently as excellent materials and were used in various catalytic reactions due to their excellent catalytic activity. Although active research on the design DACs has been ongoing for almost a decade, little attention has been paid to the detailed catalytic mechanisms. Based on density functional theory (DFT) analysis, the iron dimer embedded in N-containing graphene (FeFe@N6) has the most excellent adsorption properties of O2 and CO among DACs systems (M1M2@N6, M1/M2 = Fe, Co, Ni). We considered the influence of N atoms concentration and position on the adsorption performance and stability of the iron dimer, FeFe@N6 was screened as a potential DAC. We systematically studied the catalytic mechanisms of CO oxidation on FeFe@N6 and its monometallic counterpart (VFe@N6). CO oxidation on FeFe@N6 along the Eley–Rideal (ER) and termolecular Eley–Rideal (TER) mechanisms needs to overcome the low energy barriers of 0.513 eV and 0.299 eV, which is smaller than the maximum energy barrier (0.584 eV) of CO oxidation along the Langmuir–Hinshelwood (LH) mechanism on VFe@N6. Therefore, FeFe@N6 has high activity for CO oxidation, which can provide useful guidance for the development of low-cost and efficient green DACs.

Comparative Study of NO and CO Oxidation Reactions on Single-Atom Catalysts Anchored Graphene-like Monolayer.

Noble metal single-atom catalysts (NM-SACs) anchored at novel graphene-like supports has attracted enormous interests. Gas sensitivity, catalytic activity, and d-band centers of single NM (Pt and Pd) atoms at graphenylene (graphenylene-NM) are investigated using first-principle calculations. The adsorption geometries of gas reactants on graphenylene-NM sheets are analyzed. It is found that the adsorption energies of reactant species on graphenylene-Pt are larger than those on graphenylene-Pd, because the d-band center of the Pt atom is closeser to the Fermi level. The NO and CO oxidation reactions on graphenylene-NM are investigated via four catalytic mechanisms, including Langmuir-Hinshelwood (LH), Eley-Rideal (ER), New ER (NER), and termolecular ER (TER). The results show that the NO and CO oxidations via LH and TER mechanisms can occur owing to the relatively small energy barriers. Moreover, the interaction of 2NO+2CO via ER mechanism is the energetically more favorable reaction. Although the NO oxidation via the NER mechanism has rather low energy barriers, the reaction is unlikely to occur due to the low adsorption energy of O2 compared with CO and NO. This research may provide guidance for exploring the catalytic performance of SACs on graphene-like materials to remove toxic gas molecules.

Non-noble metal single-atom catalyst of Co1/MXene (Mo2CS2) for CO oxidation

MXene is a variety of new two-dimensional (2D) materials with early transition metal carbides, nitrides, and carbonitrides. Quantum chemical studies have been carried out on the geometries, electronic structures, stability and catalytic properties of a non-noble metal single-atom catalyst (SAC) with single Co atom anchored on MXene materials of Mo2CS2. The Co adatom anchored on top of the Mo atom of this MXene is found to be rather stable, and this SAC is appropriate for CO oxidation. The charge transfers from the surface to the adsorbed CO and O2 play a significant role in the activation of these molecules on Co1/Mo2CS2. With this catalyst, the Eley-Rideal (ER), Langmuir-Hinshelwood (LH), and Termolecular Eley-Rideal (TER) mechanisms are explored for CO oxidation. We find that, while all the three mechanisms are feasible at low temperature, Co1/Mo2CS2 possesses higher catalytic activity for CO oxidation through the TER mechanism that features an intriguing OC(OO)CO intermediate (IM) adsorbed on Co single atom. The calculated activation energy barriers of the rate-limiting step are 0.67 eV (TER), 0.78 eV (LH) and 0.88 eV (ER), respectively. The present study illustrates that it is promising to develop and design low-cost, non-noble metal SACs using MXene types of 2D materials.

Single–atom manganese and nitrogen co-doped graphene as low-cost catalysts for the efficient CO oxidation at room temperature

Room temperature, low-cost and efficient single-atom catalysts for the CO oxidation was essential for the pollutant-free biological and ecological environment. Herein, the oxidation mechanism of CO on manganese (Mn) and nitrogen (N) co-doped single-vacancy graphene (MnN-SV) and double-vacancy graphene (MnN-DV) are studied through density functional theory (DFT) calculations. The MnN-SV have a more excellent catalytic performance for CO oxidation compared to MnN-DV due to the synergistic effect of the Mn and N atoms and the ligand effect. CO oxidation on MnN-SV results into two CO2via the termolecular Eley–Rideal (TER) mechanism whose energy barrier of rate determining step (RDS) is 0.351 eV, indicating superior catalytic performance compared to the most known catalysts. In addition, MnN-SV catalyzes CO via the Langmuir-Hinshelwood (LH) mechanism with only an energy barrier of RDS is 0.727 eV, and the energy barrier for the second CO2 generated by Eley-Rideal (ER) mechanism is 0.691 eV. Technologically, present results provide a pathway for the development of an efficient and low-cost catalysts to oxidize CO at room temperature.

The coordination of Al on pyridinic-N doped graphene as electrons reservoir for efficiently catalyzing CO oxidization

Single atom catalysts (SACs) have gained paramount attention due to their superior catalytic reactivity. Herein, as the most abundant metal on earth, the aluminum (Al) was used to construct a novel SAC with configuration of Al-GN4 for catalytic oxidation of CO, where a single Al atom was coordinated with four pyridinic nitrogen atoms doped in graphene grids. Four CO catalytic oxidization mechanisms including Eley-Rideal (ER), Langmuir-Hinshelwool (LH), New Eley-Rideal (NER) and termolecular Eley-Rideal (TER) were investigated to explore the catalytic performance of Al-GN4. It was found that the energy barriers of the rate-determining step for ER, LH and NER mechanisms were in the range from 0.41 to 0.59 eV, denoting the high catalytic activity of Al-GN4. It is worthy to note that the CO oxidization via TER mechanism is nearly barrierless although the probability may be low for its high adsorption energy at the initial state. Through detailed electronic structure analysis, an Al-N-C local structure functioning as electrons reservoir for electrons collection and release during adsorption and activation of O2 was proposed. Our results may provide clues for understanding the catalytic performance of SACs, moreover, we expect it will be helpful for designing other SACs with superior activity.