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As the demand for high-capacity battery materials continues to grow, the exploration of the interaction mechanisms between Li/Na/K atoms and electrode materials has gained tremendous attention. In this study, we introduce a descriptor (ɛɑ) aimed at efficiently identifying high-performance electrode materials, specifically from two-dimensional transition metal chalcogenides and C and N compounds (MXenes). Our density functional theory calculations disclose a robust linear relationship between this descriptor and the adsorption energy (Ead), represented as Ead = ɛɑ + b. The fitting parameters, ɛɑ and b, are individually linked to the inherent properties of the substrate and adsorbate. Explicitly, the descriptor ɛɑ represents the capacity of the electrode material to accommodate an extra electron, while the intercept b is determined by the ionization energy (EIP) of alkali atoms and the coupling energy (Ecp) between the cation to the negatively charged substrate. This finding serves as a practical guide for designing high-capacity battery materials and paves the way for future advancements in this field. [ABSTRACT FROM AUTHOR]

Synthesis of Ni and nitrogen-codoped carbon nanosheets by pyrolyzing citric acid and melamine at 900 °C. Single-atom catalysts have attracted wide attention recently because of their unique size quantum effect and superior atom utilization in CO 2 reduction reaction (CO 2 RR). Here, ultrathin Ni and nitrogen-codoped carbon nanosheets (Ni- N -CNSs) were proposed by a facile in-situ pyrolytic strategy. The ultrathin porous structure of Ni- N -CNSs affords large surface area, rich mesoporous volume and vast uniformly dispersed Ni atoms. The optimized catalyst exhibits a high CO Faradaic efficiency of nearly 100%, partial current density of 121.4 mA mg−1, CO production rate of 37.7 μmol mg−1 min−1, and super durability. In addition, the first principles calculations and the Mulliken charge analyses reveal the Ni sites show high bonding force towards the CO 2 molecules, which gives rise to the high activity and selectivity of Ni- N -CNSs in CO 2 RR. [ABSTRACT FROM AUTHOR]

The development of efficient catalysts for low temperature CO oxidation is important to the application of fuel cells. In this work, we report that the Ag monolayer on WC (0001) surface (Ag ML /WC) could effectively catalyze CO oxidation through the L-H mechanism (CO + O 2 → OOCO → CO 2 + O). The most sluggish reaction step is suggested to be CO + O → CO 2 with a barrier of 0.48 eV, which is 1.21 eV lower than the barrier of O 2 dissociation. The electronic structure and d-band center analyses demonstrate that the promoted activity may originate from the synergistic effect between Ag monolayer and WC. The present study is conducive to design new efficient and cost-effective catalysts for CO oxidation without using of the noble platinum. • The AgML/WC (0001) has higher ability to adsorb small molecules compared to that of Ag (111). • The L-H and E-R mechanisms of CO oxidation on AgML/WC (0001) are comparatively studied. • The AgML/WC (0001) could effectively catalyze CO oxidation with higher activity than Pt (111). • The promoted activity may originate from the synergistic effect between AgML and WC. [ABSTRACT FROM AUTHOR]

Catalysts with fast NO oxidation kinetics and moderate adsorption towards NO 2 are urgently required for fast selective catalytic reduction of NO. Based on density functional calculations, we report in this work that Au monolayer on WC(0001) (Au/WC) has both high NO oxidation activity and strong adsorption to NO 2. The WC substrate shifts the d -band center of Au monolayer to the vicinity of the Fermi level and the binding strength of reactants on Au/WC is consequently enhanced. The rate constants of gas desorption obtained in this work are significantly lower than those of forward reactions, in accordance with previous molecule dynamics simulations. We anticipate that the present results will facilitate the development of high-performance catalysts for NO oxidation. Unlabelled Image • NO molecule will directly dissociate on pure WC(0001). • NO 2 will desorb easily from the Au(111). • Au/WC has a high activity towards NO oxidation and moderate adsorption to NO 2. • The synergistic effect between Au and WC endows the Au/WC a promising SCR catalyst. [ABSTRACT FROM AUTHOR]

The CO oxidation reaction over single-atom Pt catalyst dispersed on the defective TiC (1 0 0) surface with a Ti vacancy is studied using the dispersion-corrected density functional theory (DFT-D) computations. The stable configuration of the TiC supported single Pt atoms and the preferable CO oxidation reaction mechanisms are explored. The results demonstrate that the Pt atom may be tightly embedded in the surface Ti defect sites with a formation energy of −4.86 eV, forming a TiC supported single-atom platinum catalyst, marked as Pt@d-TiC. The adsorption characteristics of various adsorbates on Pt@d-TiC are investigated, and the Eley–Rideal (E–R) and Langmuir–Hinshelwood (L–H) mechanisms for CO oxidation on Pt@d-TiC are simulated. Specifically, it is found that all the reaction species prefer to be adsorbed on the TiC support, indicating that the support vigorously participates in the catalytic reactions. In addition, the catalytic CO oxidation reaction over Pt@d-TiC favors to start with the L–H reaction. The rate-limiting step is the formation of the peroxide-like (OCOO) intermediate complex by the coadsorbed CO and O 2 with an activation barrier of 0.91 eV. The subsequent E–R reaction has a lower energy barrier of 0.45 eV. This work clearly shows the catalytic activity of the single-atom Pt supported on TiC for CO oxidation and perhaps for other reactions. [ABSTRACT FROM AUTHOR]

The adsorption and dissociation of O 2 on the palladium and platinum modified TaC (1 0 0) surfaces were investigated based on the density functional theory calculations. It is found that the adsorption sites of O 2 are the Ta-Ta bridge sites on both the partially covered TaC (1 0 0) surfaces by Pd and Pt, M 4 /TaC (1 0 0) (M = Pd and Pt), while the 4-fold metal hollow sites and the metal-metal bridge sites are preferred on the fully covered TaC (1 0 0) surfaces by Pd and Pt monolayer, M ML /TaC (1 0 0), respectively. The deposition of Pd or Pt can enhance the oxidation resistance of TaC (1 0 0). Meanwhile, the TaC (1 0 0) decorated by monolayer Pd still exhibited outstanding catalytic activity for O 2 dissociation. Our study might be useful to designing efficient catalysts for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Defective PtX 2 (X = S, Se, Te) is an excellent structure for supporting Pt atom. • Pt 1 /PtTe 2 has high catalytic activity for CO oxidation. • The electronegativity of X atoms changes the O 2 capture ability of the substrate. • Defective monolayer TMDs can serve as excellent substrates for SACs. The geometric stability, electronic structure and catalytic properties towards CO oxidation of a single Pt atom supported on PtS 2 , PtSe 2 , PtTe 2 with a S, Se, and Te vacancies (Pt 1 /PtX 2) 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 O 2 molecules on Pt 1 /PtX 2. The results show that Pt 1 /PtTe 2 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. [ABSTRACT FROM AUTHOR]

The deposition of platinum on the tungsten carbide (Pt/WC) have been achieved and proved with high stability, activity and CO-tolerance toward some reactions in experiments. Although a lot of experimental efforts have been focused on understanding the activity, stability and CO-tolerance of Pt/WC, the relevant theoretical works related to the CO-tolerance mechanism are still scarce. In current study, the adsorption and oxidation of CO on the Pt monolayer supported on WC(0001) surface (Pt ML /WC(0001)) are investigated using density functional theory calculations. It is found that the oxidation of CO on Pt ML /WC(0001) proceeds preferably along the Langmuir-Hinshelwood mechanism. The energy barrier of 1.06 eV for the rate-determining step of OOCO formation is almost equal to that (1.05 eV) for CO oxidation by atomic O on Pt(111), while the adsorption energy of 1.59 eV for CO on Pt ML /WC(0001) is smaller than that on Pt(111) (1.85 eV), indicating that the high resistance to CO poisoning of Pt ML /WC(0001) may originate from the weak interaction between them. To further improve the CO tolerance, some probable strategies are proposed based on the relevant kinetics results. The current results are helpful to understanding the origin of the highly resistant to CO poisoning of Pt ML /WC(0001) and rationally designing catalysts to improve the CO oxidation activity. [ABSTRACT FROM AUTHOR]

The low operating temperature, high efficiency and noble-metal-free are the goal of the ideal catalysts. In present study, an efficient noble-metal-free catalyst for CO oxidation with a single cobalt atom incorporated with pyridinic nitrogen graphene (Co-N 3 -gra) is proposed. The catalytic activity for CO oxidation via various mechanisms on the Co-N 3 -gra catalyst is investigated using the first-principles method. It is found that the CO oxidation occurs preferably following the Langmuir-Hinshelwood mechanism (CO + O 2 → OOCO → CO 2 + O) with an energy barrier of 0.86 eV for the rate-limiting step of OOCO formation. Our findings prove that the activity of noble-metal-free Co-N 3 -gra catalyst is comparable to or even higher than some other single noble-metal-graphene based catalysts. [ABSTRACT FROM AUTHOR]

The growth process of Pt monolayer on ZrC(100) were investigated using density functional theory calculations. The strong interaction of Pt atoms with ZrC(100) was beneficial to improving the stability and activity of Pt catalyst. The adsorption and dissociation of O 2 on the bare and Pt modified ZrC(100) were comparably investigated, and found that the supported Pt on ZrC(100) have a positive impact on promoting the scission of the O O bond and weakening the adsorption of produced O, which shed meaningful light on the important role of ZrC(100) as support to improve the efficiency of Pt for oxygen reduction. [ABSTRACT FROM AUTHOR]

The mechanisms for oxygen reduction reaction (ORR) on the metal-free phosphorus doped graphene (P-Gra) support are investigated using the density function theory (DFT) calculations. It is found that all the ORR species can be strongly adsorbed on the P-Gra except for the H 2 O molecule. Our calculation results show that all of the possible ORR elementary reactions could take place within a small region around the dopant and the ORR could proceed firstly by a 2e − process to form an OOH intermediate, which is followed by the 4e − process to break the O–O bond of OOH. Along this reaction path, the reduction of the second OH to H 2 O is the rate-limiting step with the largest barrier of 0.88 eV. To the best of our knowledge, this is the first theoretical investigation on the mechanisms for the entire process of the ORR on the P-Gra. [ABSTRACT FROM AUTHOR]

• Graphene improves the electrical conductivity of iron phthalocyanine molecules. • The iron phthalocyanine exhibits different OER activity on various graphene substrates. • The defective graphene most promoted the OER activity with potential of 0.45 V. • The activity origin is the moderate adsorption of oxygen-containing intermediate by iron atoms. Electrolysis of water is a clean, sustainable and efficient way to produce hydrogen, and will be indispensable among the production of renewable energy in the future. The oxygen evolution reaction (OER) plays a key role of water decomposition. Here, we attached iron phthalocyanine to graphene, and explored the influence of different graphene substrates to catalytic activity using the first-principles methods based on density functional theory. Graphene improves the dispersion and electrical conductivity of iron phthalocyanine molecules, and facilitates its OER activity. The introduction of substrate promotes the electron transfer between FePc and the oxygen-containing intermediates. The results indicated that the iron phthalocyanine exhibits different OER activity on various graphene substrates, among which the defective graphene most promoted the OER activity. The improved activity is originated from the axial interaction between the iron and carbon atoms on the defective graphene, leading to a moderate adsorption of oxygen-containing intermediates. Our study provides a reference for the regulation of molecular catalyst activity. [Display omitted] [ABSTRACT FROM AUTHOR]

The integrated mechanism of the catalytic oxidation of NO by NO on the metal-free support of nitrogen doped graphene (NG) is investigated using density function theory calculations. The results indicate that the NO can be intensively adsorbed on NG support, while the NO, N, NO are all weakly adsorbed. In the oxidation process, a two-step mechanism is identified: the dissociation of NO followed by the oxidation of NO with the dissociative O-atom. The present work suggests that the NG support, as a high-efficient and metal-free catalyst, is one of the promising candidates for removing the nitrogen oxides gases exhaust. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface alloying could stabilize the supported monolayer structure. • Alloy monolayers on tungsten carbide exhibit enhanced HER activity. • The doping modes and ratio play an important role in modulating the stability and activity. • Superior HER activity of Cu 2 Au 7 d@WC(0001) is identified. Rational design of supported catalysts with alloy monolayer on suitable substrate is of crucial importance for reducing the cost and enhancing the catalytic activity. In this work, the reactivity of Cu-Au alloy monolayer supported on WC for HER is investigated using density functional theory (DFT) calculations, and the results are compared with those of the supported pure monolayer ones. It is found that the Cu-Au alloy monolayers on WC exhibit enhanced stability and tunable HER activity. Superior activity of Cu 2 Au 7 d@WC(0001) for HER (ΔG = 0.007 eV) is identified according to the calculated Gibbs free energy and the exchange current density. Geometric and electronic analyses enable to a deep understanding on the important role of the specific configuration and ratio of Cu and Au for moderate H adsorption. Cu doping leads to the synergistic ligand and stress effects in the alloy systems, which further optimize the adsorption characters and the charge redistribution around the dopants, which is essential to the high HER activity. The present study sheds light on the significance of alloy effects on tuning the geometric stability and electronic properties as well as the catalytic activity, which may benefit to the rational design and development of supported alloy materials. [ABSTRACT FROM AUTHOR]

The improved electron acceptability of phthalocyanine/ketjenblack compounds can enhance the adsorption strength of the *COOH and inhibit the rival HER in ECR, thus showing extremely high synergistic catalytic activity for converting CO 2 to CO. • NiPc/KB was synthesized by a rapid and facile one-step in-situ π-π stacking method. • TOF for converting CO 2 to CO is enhanced by greater than 251 times. • Faradaic efficiency for CO reaches to 98.2%. • DFT calculations reveal the synergistic catalytic processes of NiPc/KB in ECR. Designing a facile and high-yield strategy to prepare highly active and selective electrocatalysts for CO 2 reduction is beneficial to the industrial application. However, there are still many challenges in catalyst preparation. Besides, further mechanism studies on catalytic process for enhancing CO 2 reduction are not clear. Herein, We have found that nickel phthalocyanine facilely incorporated into defect-rich ketjenblack by π-π stacking method can greatly improve its ECR performance. Nickel phthalocyanine/ketjenblack compounds show high selectivity and activity, 251 times turnover frequency for converting CO 2 to CO compared to pristine nickel phthalocyanine, and keep above FE CO of 90% under large potentials regions from −0.65 to −1.05 V vs RHE. Fundamentally density functional theory (DFT) calculations reveal that nickel phthalocyanine molecules anchored onto ketjenblack enhance the electron acceptability, decrease the formation energy of the *COOH and inhibit the rival hydrogen evolution reaction (HER), thus showing extremely high synergistic catalytic properties in ECR. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) is one of the most important reactions in renewable energy conversion and storage devices. The full deployment of these devices depends on the development of highly active, stable, and low‐cost catalysts. Herein, a new hybrid material consisting of Na2Ta8O21−x/Ta2O5/Ta3N5 nanocrystals grown on N‐doped reduced graphene oxide is reported. This catalyst shows a significantly enhanced ORR activity by ≈4 orders of magnitude in acidic media and by ≈2 orders of magnitude in alkaline media compared to individual Na2Ta8O21−x on graphene. Moreover, it has excellent stability in both acid and alkaline media. It also has much better methanol tolerance than the commercial Pt/C, which is relevant to methanol fuel cells. The high ORR activity arises not only from the synergistic effect among the three Ta phases, but also from the concomitant nitrogen doping of the reduced graphene oxide nanosheets. A correlation between ORR activity and nitrogen content is demonstrated. Deep insights into the mechanism of the synergistic effect among these three Ta‐based phases, which boosts the ORR's kinetics, are acquired by combining specific experiments and density functional theory calculations. [ABSTRACT FROM AUTHOR]

Spin-unrestricted density functional theory (DFT) calculations are performed to explore the electronic structure and water-gas shift (WGS) behavior for the non-polar (001) surface of both titanium carbide (TiC) and titanium nitride (TiN). Previous researches have suggested that the unique electronic structures of these materials can effectively explain their surface adsorption and reactivity. Herein, our DFT calculations demonstrate that TiC(001) surface with occupied nonmetal C-2p states strongly binds CO molecule to the carbon site, and subsequently mediates the WGS along an associative mechanism. In contrast, TiN(001) surface dominated by metal Ti-3d states prefers to adsorb CO molecule at the titanium site, and then mediates WGS reaction through a redox mechanism. This indicates that the surface behavior of TiC(001) and TiN(001) is strongly dependent on their own electronic structure as expected. Therefore, the present studies provide an interesting perspective to understand the correlation between the electronic structure and catalytic behavior of such materials. Unlabelled Image • The difference in electronic structure is for TiC(001) with C-2p feature and for TiN(001) with Ti-3d character. • The WGS reaction on TiC(001) follows associative mechanism, while on TiN(001) goes through redox mechanism. • Substituting nonmetal elements in TiC and TiN can change electronic structure and reactivity of such materials. [ABSTRACT FROM AUTHOR]

The adsorption of Au dimer on MgO(100), CaO(100), BaO(100), TiO 2 (110) and YSZ(100) surfaces is comparatively studied using ab initio density functional theory calculations. It is found that Au dimer prefers upright adsorption on MgO(100), CaO(100), BaO(100) surfaces and parallel adsorption on TiO 2 (110) and YSZ(111) surfaces. According to the analysis of the metal-metal cohesive energy (E Au-Au ) and the metal-substrate adhesion energy (E Au-Support ), we find that Au adatoms prefer 2D cluster on BaO(100) and TiO 2 (110) surfaces and 3D cluster on MgO(100), CaO(100) and YSZ(111) surfaces. We also find a linear relationship between E Au-Support /E Au-Au and E b (binding energy of metal atom on the substrate). Furthermore, an interesting correlation between association energies and the amount of transferred charge is found. The findings may help to gain further insight into the structure-property correlation and provide valuable information on crucial parameters in catalyst design. [ABSTRACT FROM AUTHOR]

• The charge transfer between ZrC and Pd atoms benefits the catalytic performance. • The coverage of Pd plays an important role in adsorption and dissociation of O 2. • Pd ML /ZrC(0 0 1) is expected to be a promising substitute for Pt/C catalyst. • ZrC(0 0 1) may serve as a good support for noble metals. We propose the Pd monolayer (ML) on ZrC(0 0 1) surface as an effective catalyst for the dissociation of oxygen by density functional theory calculations. We find that the coverage of Pd has a conspicuous impact on the adsorption and dissociation of O 2. The strong interaction between the Pd atoms and the ZrC(0 0 1) support enhances the reactivity and stability of the electrocatalyst. By comparing the binding energies of Pd-Pd and Pd-C, we conclude that the Pd adatoms do not aggregate to form a cluster and prefer to form a monolayer when the coverage is low. With a monolayer of coverage, the C sites are fully saturated by adsorbed Pd atoms, which prevent the oxidation of the ZrC(0 0 1) surface. The dissociation activity of O 2 on Pd ML /ZrC(0 0 1) is predicted to be a rival of or even surpass Pt(1 1 1). In addition, the high mobility of the dissociated oxygen atoms on Pd ML /ZrC(0 0 1) also benefits the later reaction step for ORR. [ABSTRACT FROM AUTHOR]