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• Optimal path for ethyl acetate as a byproduct of vinyl acetate synthesis by ethylene method. • Adsorption properties of PdAu(100) surface species during ethyl acetate generation. • The combination of density functional theory and kinetic Monte Carlo method. Vinyl acetate (VAc) is an important chemical raw material for the production of polyvinyl alcohol and polyvinyl acetate, among others. The preparation of vinyl acetate over PdAu catalysts using ethylene, oxygen and acetic acid as raw materials is one of the mainstream processes for the production of vinyl acetate in the world. The by-product ethyl acetate in this process is more difficult to be completely removed, and it is an impurity component in vinyl acetate products that needs to be strictly controlled in content. However, studies on the mechanism of ethyl acetate generation have not been reported, which limits the improvement of the purity of vinyl acetate products and the optimization of the ethyl acetate separation process. In this paper, the mechanism of ethyl acetate generation during ethylene vinyl acetate reaction on PdAu catalysts was systematically investigated using a combination of density functional theory (DFT) and kinetic Monte Carlo (kMC) simulations. The results show that the species tend to adsorb to the Pd-Au bridge sites, diagonal Pd-Pd vacancies, and diagonal Pd-Au vacancies of PdAu(100), and the Pd on the catalyst surface interacts more strongly with the adsorbed species. The dominant pathway for the generation of ethyl acetate on PdAu(100) is CH 2 CH 2 * + O *→ CH 2 CH* + H * → CH 3 CH* + CH 3 COO* → CH 3 COOCHCH 3 * + H * → CH 3 COOCH 2 CH 3 *, where the hydrogenation of CH 2 CH* to CH 3 CH* is the rate-control step in the dominant pathway for the generation of ethyl acetate. This step has an energy barrier of 1.09 eV and a reaction heat of 0.90 eV. The study of the generation mechanism of the by-product ethyl acetate in this paper is hoped to provide more targeted guidance and suggestions for the modification of Pd-Au catalysts, so as to reduce the generation of ethyl acetate as a by-product, to reduce the energy consumption required for the separation, and to enhance the purity of vinyl acetate products. [Display omitted] [ABSTRACT FROM AUTHOR]

• Sc @BB is a promising electrocatalyst towards NRR. • The NRR performance of Sc @BB could be further improved by strains. • The NRR performance of TM@BB is related to the intrinsic properties of TMs. NH 3 plays an important role in industrial production, while it is still a challenge to develop a promising catalyst for NH 3 synthesis. In particular, the metal borides have attracted much attention because of their excellent catalyst performances towards N 2. In this paper, we have theoretically studied the N 2 reduction reaction (NRR) by employing the transition metal (TM = Co, Cr, Cu, Fe, Mn, Mo, Ni, Sc , Ti, V, Zn, Nb, Pd, Rh, Ru or Zr) doped bilayer borophene (BB). After the screening, it is found that Sc -doped BB (Sc @BB) exhibits excellent NRR performance with the limiting potential of -0.43 V, and the hydrogen evolution reaction (HER) could be well suppressed. The limiting potential could be further improved into -0.40 V by applying 0.30 % uniaxial strains to the system. In addition, the machine learning method was employed to understand the catalytic mechanism, the results revealed that the NRR performance of TM@BB is strongly related to the inherent properties of TM atoms, such as the d -electron number, electronegativity, first ionization energy, atomic radius, and atomic number. Therefore, our paper not only proposed a promising electrocatalyst for NRR, but also further extend the application of transition metal-boron based two dimensional materials in NRR. [Display omitted] [ABSTRACT FROM AUTHOR]

• The mechanism of inhibiting the generation of methane and improving the selectivity of olefin on the Co(020) surface was found. • The paper investigates the reaction mechanism and elementary reaction kinetics of the cobalt carbide-catalysed FTO process by quantum mechanical methods. • The DFT study of Fischer–Tropsch synthesis of low carbon olefins on Co 2 C is limited to C 1 and C 2 species. In this paper, the generation mechanism of ethylene, propylene and butene will be further studied. Fischer–Tropsch Synthesis to lower olefins (FTO) is an important non-petroleum route to produce lower olefins. Nanoprisms Co 2 C has been discovered as a promising FTO catalyst possessing high selectivity to olefins and low CH 4 selectivity for its exposing (020) facet. Density Functional Theory (DFT) was used to understand the reason for inhibiting methane formation, the chain growth mechanism and dominant formation pathway of three main low olefins. The results show that the activation energy for CH 2 * to couple with CH* (0.51 eV) was much lower than that for further hydrogenation to form CH 3 * (0.66 eV), which was the key species to produce methane. Therefore, the mechanism inhibiting methane formation was Co 2 C(020) promoting CH 2 *-CH*coupling rather CH 2 * hydrogen. Moreover, it can be predict that the carbon chain would not grow too long, because the coupling activation energy for the C 1 -C 1 coupling, C 1 -C 2 coupling, C 1 -C 3 coupling were 0.51 eV, 0.54 eV and 0.69 eV, respectively. At last, it can be predicted that propylene was the easiest to produce, followed by ethylene and butylene, because their barrier energy were 1.58 eV, 1.64 eV and 2.12 eV, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

• DFT and microkinetic modeling were performed to study the mechanism of the propane dehydrogenation over Pd(100), Pd(210), Pd 3 Bi 1 (100), Pd 2 Bi 1 (100), Pd 1 Bi 1 (100), and Pd 1 Bi 1 (210). • With the increase of the Bi concentration, the ε d of the surface layer moves to the lower energy, and the propylene bonding strength decreases. AIMD finds the temperature at which propylene begins to desorb also decreases. • Two selectivity descriptors (Δ E selec, 1 and Δ E selec,2) succeed in predicting the propylene selectivity on the pure Pd and Pd-Bi intermetallic compounds, because the barriers for both C-C crack and propylene deep dehydrogenation approximately increase with Bi concentration. • Under typical reaction conditions, the apparent activation energies are 1.04, 1.34, 1.78, and 2.07 eV on the Pd(100), Pd 3 Bi 1 (100), Pd 2 Bi 1 (100), and Pd 1 Bi 1 (100), respectively. And the propylene selectivity increases from 0.64 on the Pd(100) to 0.99 on the Pd 1 Bi 1 (100). • The isolated Pd sites on the Pd 1 Bi 1 (100) and Pd 1 Bi 1 (210) result in a relatively high e a eff for propane dehydrogenation and a lower TOF of propylene. As a compensation between activity and selectivity, the Pd 2 Bi 1 (100) may be more suitable for PDH. Propylene is an important industrial raw material. The high temperature needed by the propane dehydrogenation (PDH) on the pure Pt or Pd catalyst may give rise to hydrogenolysis and carbon deposition, which ultimately poisons the catalysts. Experiments synthesized a series of Pd-Bi intermetallic compounds loaded on SiO 2. The Pd-Bi/SiO 2 catalyst with a moderate Bi concentration bears high activity and selectivity. But the reason is unknown. In the present paper, the DFT calculation and microkinetic modeling were performed to study the reaction network of PDH on the Pd(100), Pd 3 Bi 1 (100), Pd 2 Bi 1 (100), Pd 1 Bi 1 (100), Pd(210), and Pd 1 Bi 1 (210). Due to the isolated Pd sites, Pd 1 Bi 1 (100) and Pd 1 Bi 1 (210) showed the highest propylene selectivity but low TOF of propylene. The Pd 2 Bi 1 (100) may be more suitable for PDH because of the compensation between activity and selectivity. Two selectivity descriptors (Δ E selec, 1 and Δ E selec, 2) could measure the influence of deep dehydrogenation and hydrogenolysis on the selectivity for propylene in the PDH, respectively. The barriers for both C-C crack and propylene deep dehydrogenation approximately increase with Bi concentration, which may be why both Δ E selec, 1 and Δ E selec, 2 succeed in predicting the propylene selectivity on the pure Pd and Pd-Bi catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• Optimized pathway for the production of methyl acetate as by-product in the gas-phase synthesis of vinyl acetate from ethylene. • Adsorption properties of species on PdAu(100) surface during methyl acetate generation. • The combination of density functional theory and kinetic Monte Carlo method. Methyl acetate is a byproduct that is difficult to completely remove in the gas-phase process of producing vinyl acetate from ethylene. High-quality vinyl acetate products require stringent control of the methyl acetate content. However, studies on the mechanism of methyl acetate formation have not been reported, which constrains the modification of catalysts to reduce its formation. This paper presents a comprehensive study on the generation mechanism of methyl acetate during the ethylene-based vinyl acetate synthesis process over PdAu catalysts, utilizing a combination of DFT (Density Functional Theory) and kMC (kinetic Monte Carlo) simulations. The reaction network for the formation of methyl acetate on PdAu catalysts was constructed. Initially, DFT calculations were employed to investigate the adsorption properties of relevant species on the PdAu(100) surface. The results indicate that surface species preferentially adsorb at the Pd-Au bridge sites, diagonal Pd-Pd hollows, and diagonal Pd-Au hollows on the PdAu(100) catalyst, with a stronger interaction between the Pd atoms and the adsorbed species. Subsequently, DFT calculations were performed to identify the optimal pathways for the generation of methyl acetate on PdAu(100). Based on the kinetic parameters obtained from DFT calculations, kMC simulations were conducted to stimulate the generation process of methyl acetate. The results demonstrate that the dominant pathway for the formation of methyl acetate during the ethylene-based vinyl acetate synthesis over PdAu(100) is through CH 2 CH 2 * + O * → CH 2 CH * + H * → CH 3 CH * → CH 3 * + CH * ( CH * + H * → CH 2 * + H * → CH 3 *) → CH 3 * + CH 3 COO * → CH 3 COOCH 3 *. The reaction between CH 3 COO* and CH 3 * to form methyl acetate is identified as the rate-determining step, with an energy barrier of 1.75 eV and an exothermic reaction heat of −0.53 eV. [Display omitted] [ABSTRACT FROM AUTHOR]

• Secondary and tertiary carbamates are prepared in high efficiency in an unprecedentive strategy. • Active transition metal-functionalized MOFs are synthesized via an in situ -grown protocolunder solvent-free mechanochemical conditions. • Both aminesand aniline are well tolerated. The solvent-free synthesis of MOF represents a promising and environmentally benign protocol. This paper outlines a green one-pot mechanochemical method for the synthesizing of UiO-66 in the absence of solvent, along with the implantation of three different metals (Cu, Ni, and Pd) into the defect sites. The materials have proven to be effective catalysts in the transformation between azidocarbonate and amines/anilines in moderate to excellent isolated yields (up to 94%), exhibiting better advantages compared with the exiting methodologies. More interestingly, Cu and Ni exhibited very good catalytic performance towards primary and secondary amines, respectively. It also should be noted that high yield was still observed after six cycles. Our work presents a novel and straightforward strategy for the preparation of secondary and tertiary carbamates in an unprecedented fashion, greatly enriched the toolbox for the synthetic community. Moreover, the combination of experimental studies and density functional theory (DFT) calculations gave more insight and evidence for the mechanism. Accompanied by the advantages of the effective and recyclable catalyst, the broad substrate scope, good functional group tolerance, and excellent reaction yields made the established method attractive in heterogeneous catalysis and the carbamates synthesis. [Display omitted] [ABSTRACT FROM AUTHOR]

• Multi-molecules adsorption configuration with CO on Mn while O 2 on P can be easily achieved on MnP 4 -Gr. • Fast LH processes is predicted to be proceeding. • The atomic oxygen removal from P atom determines the whole reaction on MnP 4 -Gr. • Cooperation of Mn and P is evidenced to promote CO oxidation on MnP 4 -Gr. Computational studies show that the co-doping of Mn and P atoms in graphene (MnP 4 -Gr) can provide high CO oxidation performance at room temperature. Results suggest that the configuration (CO+O 2)* can be easily obtained due to the better adsorption of CO on the Mn atom and O 2 on the P atom. (CO+O 2)* is further found to undergo a fast Langmuir−Hinshelwood (LH) process and then left one atomic oxygen on P which is difficult to remove. Therefore, due to the more favorable adsorption of CO on the Mn atom and O 2 on other P atoms, coupled with the speed of the LH process, the configuration (CO+4O)* of one atomic oxygen adsorbed on each P atom and CO on Mn atom is finally obtained. The whole reaction is determined by the atomic oxygen removal in (CO+4O)* with an energy barrier of 0.80 eV. It is predicted that the cooperation of Mn and P atoms is conducive to the fast LH process of MnP 4 -Gr and also the weaker binding between P and O in MnP 4 -Gr. Moreover, thermodynamic and kinetics analysis indicates that increasing temperature can accelerate CO oxidation and facilitate reaction in thermodynamics. Therefore, the insights reported in this paper will provide a new catalyst for low-temperature CO oxidation. [Display omitted] [ABSTRACT FROM AUTHOR]

• CuO-NiO complex metal oxides catalyzed glycerol production of lactic acid. • Significant heterogeneous junctions were observed by HRTEM. • CuO1NiO2 has excellent catalytic activity (90.08 % lactic acid yield). • DFT calculations revealed that Cu-Ni composite metal oxides are more likely to adsorb glycerol. • The differential charge density verifies that the formation of heterojunctions promotes charge transport and enhances electronic synergies. One of the most essential techniques to achieve effective usage of the principal by-product (glycerol) in the manufacturing of biodiesel is catalytic conversion of glycerol to lactic acid. In this paper, CuO-NiO composite metal oxides with different Cu/Ni molar ratios were prepared by co-precipitation method to catalyze the conversion of glycerol to lactic acid in alkaline medium. By using XRD, SEM, TEM, BET, XPS, and H 2 -TPR characterisation, the catalysts' crystalline phase, shape, and performance were assessed. The results show that the electronic synergy of CuO-NiO composite metal oxides plays a positive role in catalyzing the conversion of glycerol to lactic acid. The production of lactic acid might reach 90.08 % when Cu/Ni molar ratio (CuO1NiO2) and reaction conditions are optimum. In conjunction with the analysis using Density Functional Theory: due to the formation of heterojunctions in CuO1NiO2 the formation of good contacts between the atoms at the CuO and NiO interfaces is conducive to promoting charge transfer and electron mobility, thus enhancing the synergistic effect of electron transfer. Meanwhile, DFT calculations revealed that the Cu-Ni composite metal oxides had stronger adsorption energy for glycerol, which favored the bonding of glycerol on their surfaces. The prepared CuO-NiO composite metal oxides were used to catalyze the conversion of glycerol to lactic acid. [Display omitted] [ABSTRACT FROM AUTHOR]

• BN nanocages were constructed for synergistically curvature-polarity regulation. • Curved BN nanocages provide chemical anchoring sites for the HCHO molecules. • A multi-channel electron balance transfer mechanism formed in curved BN surface. • Curved BN nanocages present dual-catalytic sites to accelerate HCHO oxidation. Development of efficient catalysts for formaldehyde (HCHO) oxidation is of importance in indoor air pollution treatment. However, the robust design criteria remain greatly challenging because of the poor recognization of structure-function relationships. Herein, by means of density functional theory (DFT) calculations, we proposed a surface modulation strategy to optimize the surface polar bonding state of BN, proving a curvature tuned B–N–B active sites and its relationship with catalytic activity. The results indicated that HCHO can be efficiently adsorbed by the curved BN nanocage with exceptional chemisorption efficiency (up to 97 %) and even under high coverage (two molecules, 86 %). Moreover, the distortion of BN nanocage facilitates the electron transfer from electron-rich O atom of HCHO to B 2p orbital, and then transfer to O 2 via the B–N polar bond, leading to the implementation of HCHO chemisorption and O 2 activation. Thus, a multi-channel for interactive electron transfer was spatially built for the HCHO oxidation on BN nanocage. Finally, a novel BN nanocage initiated advanced HCHO oxidation mechanism, combining the curvature and polarity catalytic effects, is systematically investigated based on reaction-kinetic studies. These findings shed new light on the rational design of HCHO oxidation catalysts and broadened the applications of BN-based materials. In this paper, a strategy of "synergistically curvature and polarity bond regulation" is reported to effectively modulate the electronic structure of BN surface sites to form a multi-channel electron balance transfer mechanism between HCHO/O 2 and catalyst. Benefiting from the curvature-enhanced polarization effect, the curved BN catalyst displays excellent adsorption and catalytic oxidation performance for HCHO. [Display omitted] [ABSTRACT FROM AUTHOR]