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In this work, we have proposed a Continuous Constant Potential Model (CCPM) based on grand canonical density functional theory for describing the electrocatalytic thermodynamics on single atom electrocatalysts dispersed on graphene support. The linearly potential-dependent capacitance is introduced to account for the net charge variation of the electrode surface and to evaluate the free energetics. We have chosen the CO2 electro-reduction reaction on single-copper atom catalysts, dispersed by nitrogen-doped graphene [CuNX@Gra (X = 2, 4)], as an example to show how our model can predict the potential-dependent free energetics. We have demonstrated that the net charges of both catalyst models are quadratically correlated with the applied potentials and, thus, the quantum capacitance is linearly dependent on the applied potentials, which allows us to continuously quantify the potential effect on the free energetics during the carbon dioxide reduction reaction instead of confining it to a specific potential. On the CuN4@Gra model, it is suggested that CO2 adsorption, coupled with an electron transfer, is a potential determining step that is energetically unfavorable even under high overpotentials. Interestingly, the hydrogen adsorption on CuN4@Gra is extremely easy to occur at both the Cu and N sites, which probably results in the reconstruction of the CuN4@Gra catalyst, as reported by many experimental observations. On CuN2@Gra, the CO2RR is found to exhibit a higher activity at the adjacent C site, and the potential determining step is shifted to the *CO formation step at a wide potential range. In general, CCPM provides a simple method for studying the free energetics for the electrocatalytic reactions under constant potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pd-H x (Hδ-) and ZrO 2 -(OH) x can be formed by interfacial water dissociation. • The Hδ+ undergo the proton coupled electron transfer (PCET) from Pd to form Hδ-. • The spatial separation of H and OH in water results in the interface polarization. • The metal-support polarization promotes their interaction and flattens Pd cluster. • The formed Pd-hydrides could behave as the new active phase in CO oxidation. The supported metal catalysts are usually prepared and widely applied in aqueous phase. Here, by performing density functional theory calculations and ab initio molecular dynamics simulations with explicit solvent waters, the metal-support interaction of Pd@ZrO 2 catalyst was found to be enhanced by water dissociation at the metal-support interface. This happens to an appreciable number of interfacial waters, generating ∼ 25% hydrides compared to Pd atoms. After the partially heterolytic water dissociation, the generated Hδ+ would undergo the proton coupled electron transfer (PCET) from Pd to form the hydride (Hδ-). The spatial separation of the generated H on Pd and remaining OH on ZrO 2 results in the polarization of metal-support interface, which then flattens the shape of cluster. Moreover, the formed metal-hydride behaves as the new catalytic active phase for CO oxidation, making the catalyst highly active in water vapor. [ABSTRACT FROM AUTHOR]

The rational design of electrocatalysis has emerged as one of the most thriving means for mitigating energy and environmental crises. The key to this effort is the understanding of the complex electrochemical interface, wherein the electrode potential as well as various internal factors such as H‐bond network, adsorbate coverage, and dynamic behavior of the interface collectively contribute to the electrocatalytic activity and selectivity. In this context, the authors have reviewed recent theoretical advances, and especially, the contributions to modeling the realistic electrocatalytic processes at complex electrochemical interfaces, and illustrated the challenges and fundamental problems in this field. Specifically, the significance of the inclusion of explicit solvation and electrode potential as well as the strategies toward the design of highly efficient electrocatalysts are discussed. The structure‐activity relationships and their dynamic responses to the environment and catalytic functionality under working conditions are illustrated to be crucial factors for understanding the complexed interface and the electrocatalytic activities. It is hoped that this review can help spark new research passion and ultimately bring a step closer to a realistic and systematic modeling method for electrocatalysis. [ABSTRACT FROM AUTHOR]

The catalytic hydrogenation of biomass-derived chemicals is essential in chemical industry due to the growing demand for sustainable and renewable energy sources. In this study, we present a comprehensive theoretical investigation regarding the hydrogenation of glycolaldehyde to ethylene glycol over a Ru/C catalyst by employing density functional theory and ab initio molecular dynamics simulations. With inclusion of explicit solvation, we have demonstrated that the glycolaldehyde hydrogenation is significantly improved due to the fast proton transfer through the hydrogen bond network. The enhanced activity could be attributed to the participation of the solvent water as the hydrogen source and the highly positively charged state of a Ru cluster in an aqueous phase, which are critical for the activation of aldehyde groups and proton-assisted hydrogenation. Overall, our findings provide valuable insights into glycolaldehyde hydrogenation over Ru/C catalysts in the aqueous phase, highlighting the importance of solvation effects in the biomass conversion. [ABSTRACT FROM AUTHOR]

Dynamics of intrinsic defects are considered fundamental in the chemistry of reducible oxides, and their effect on catalytic reactions have been rarely reported. Herein, we propose a new Ov diffusion assisted Langmuir–Hinshelwood mechanism for CO oxidation, which may largely account for the origin of high reactivity of supported atomic gold catalysts. [ABSTRACT FROM AUTHOR]

Preparing metal single-atom materials is currently attracting tremendous attention and remains a significant challenge. Herein, we report a novel core-shell strategy to synthesize single-atom materials. In this strategy, metal hydroxides or oxides are coated with polymers, followed by high-temperature pyrolysis and acid leaching, metal single atoms are anchored on the inner wall of hollow nitrogen-doped carbon (CN) materials. By changing metal precursors or polymers, we demonstrate the successful synthesis of different metal single atoms dispersed on CN materials (SA-M/CN, M = Fe, Co, Ni, Mn, FeCo, FeNi, etc.). Interestingly, the obtained SA-Fe/CN exhibits much higher catalytic activity for hydroxylation of benzene to phenol than Fe nanoparticles/CN (45% vs 5% benzene conversion). First-principle calculations further reveal that the high reactivity originates from the easier formation of activated oxygen species at the single Fe site. Our methodology provides a convenient route to prepare a variety of metal single-atom materials representing a new class of catalysts. [ABSTRACT FROM AUTHOR]

Many reactions required for the upgrading of biomass into fuels and chemicals—hydrogenation, hydrodeoxygenation, hydrocracking—are ostensibly similar to those practiced in the upgrading of petroleum into fuels. But, repurposing hydroprocessing catalysts from refinery operations to treat bio-oil has proved to be unsatisfactory. New catalysts are needed because the composition of the biogenic reactants differs from that of petroleum-derived feedstocks (e.g. the low concentration of sulfur in cellulose-derived biomass precludes use of metal sulfide catalysts unless sulfur is added to the reaction stream). New processes are needed because bio-oils oligomerize rapidly, forming intractable coke and “gunk”, at temperatures so low that the desired upgrading reactions are impractically slow, and so low that the bio-oil upgrading must be handled as a condensed fluid. Ideally, the new catalysts and processes would exploit the properties of the multiple phases present in condensed bio-oil, notably the polarizability and structure of the fluid near a catalyst’s surface in the cybotactic region. Molecular simulation results of the cybotactic region adjacent to different catalyst surfaces in the hydrogenation of phenol suggest that Pd catalysts supported on hydrophilic surfaces are more active than catalysts based on lipophilic supports because the former serve to enhance the concentration of the phenol in the vicinity of the Pd. The effect stems from thermodynamics, not the rate of mass transport. [ABSTRACT FROM AUTHOR]

Abstract: The mechanisms of hydrazine decompositions on Ir(111) have been investigated by using slab model based on periodic density functional theory (DFT). In order to shed light on the elementary radical reaction processes of hydrazine decomposition on Ir-based catalysts, three possible reaction pathways are considered. Through computational modeling we have investigated the adsorption characteristics, geometrical structures, activation energies, and reaction mechanisms. The initial reactants, transition states, and final products of each elementary step and various likely intermediates are discussed. We have found that the main reaction channel with relatively low energy barriers is the following: the thermal decomposition of hydrazine forms two NH2 radicals, which attack an adjacent adsorbed hydrazine molecule or subsequent N2H x (x =1–3) species and capture the H atoms step by step, finally leading to the formation of N2 and NH3 products. We show that the rate-determining step involves NH2 interacting with a N2H species, with an energy barrier of 0.63eV (or 14.5kcal/mol). The overall reaction channel releases a large amount of thermal energies. The decomposition of hydrazine on Ir surfaces is therefore both thermodynamically and kinetically favorable. The other reaction channels investigated have much higher activation barriers with Ir catalysts. [Copyright &y& Elsevier]

Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self‐contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post‐passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes. [ABSTRACT FROM AUTHOR]

Borophenes have sparked considerable interest owing to their fascinating physical characteristics and diverse polymorphism. However, borophene nanoribbons (BNRs) with widths less than 2 nm have not been achieved. Herein, we report the experimental realization of supernarrow BNRs. Combining scanning tunneling microscopy imaging with density functional theory modeling and ab initio molecular dynamics simulations, we demonstrate that, under the applied growth conditions, boron atoms can penetrate the outermost layer of Au(111) and form BNRs composed of a pair of zigzag (2,2) boron rows. The BNRs have a width self‐contained to ∼1 nm and dipoles at the edges to keep them separated. They are embedded in the outermost Au layer and shielded on top by the evacuated Au atoms, free of the need for post‐passivation. Scanning tunneling spectroscopy reveals distinct edge states, primarily attributed to the localized spin at the BNRs' zigzag edges. This work adds a new member to the boron material family and introduces a new physical feature to borophenes. [ABSTRACT FROM AUTHOR]

The rationale for low performances in perovskite solar cells with buried interface still needs to be clarified, owing to the complicated physiochemistry of metal oxides/perovskite interface, and literature offers a meager knowledge about the reactions at this interface. While exploring the SnO2/perovskite interfacial interactions, the reasons behind deteriorating perovskite at the interface are comprehensively investigated, and it is revealed that the PbI2 residue and metallic Pb0 are the byproducts of this decomposed perovskite. Introducing an optimized amount of Ti3C2TX at the SnO2/perovskite interface detaches the SnO2 hydroxyls, which are found to be responsible for interfacial ion migrations. In addition, Ti3C2TX passivates the interface defects via its functional groups and establishes ballistic pathways for electrons with high chances of non‐radiative recombination. Thus, 25.19% (certified as 24.41%) of efficiency with superior long‐term operational stability is achieved. [ABSTRACT FROM AUTHOR]

To investigate the sleep quality and mental health status of healthcare professionals during the outbreak of coronavirus disease 2019 (COVID-19) in order to promote timely intervention and treatment. An Questionnaire Star of WeChat online survey was conducted at Hwamei Hospital, University of Chinese Academy of Sciences, NingBo, China. The questionnaire consisted of two parts including sociodemographic characteristics, and the Pittsburgh Sleep Quality Index (PSQI), the Generalized Anxiety Disorder (GAD-7) scale, a depression screening scale (Patient Health Questionnaire-9 [PHQ-9]) so as to investigate the sleep quality and mental health status of healthcare professionals during the outbreak of COVID-19.The data were analyzed with the t-test, χ2 test, one-way analysis of variance (ANOVA) and Pearson correlation, P < 0.05 was considered statistically significant. The mean score of PSQI is 5.8 ± 3.7 and the incidence of sleep disorders was 28.8% among the healthcare professionals and was related to occupation, title, education level, role and some underlying diseases. The positive rates for anxiety and depression among the healthcare professionals were 33.2% and 39.4% according to the GAD-7 and PHQ-9. Mental health status was related to occupation, education level, role and some underlying diseases. During the COVID-19 outbreak, sleep quality was significantly correlated with anxiety and depression among the healthcare professionals. The incidences of sleep disorder, anxiety and depression among healthcare professionals have been high. Furthermore, these disorders are interrelated and require timely intervention and treatment. [ABSTRACT FROM AUTHOR]

In this work, density functional theory (DFT) calculations were used to investigate the mechanism of carbon corrosion on nitrogen-doped carbon support. Free energy diagrams were generated based on three proposed reaction pathways to evaluate corrosion mechanisms. The most energetically preferred mechanism on nitrogen-doped carbon was determined. The results show that the step of water dissociation to form #OH was the rate-determining step for gra-G-1N (graphene doped with graphitic N) and pyrr-G-1N (graphene doped with pyrrolic N). As for graphene doped with pyridinic N, the step of C#OC#O formation was critical. It was found that the control of nitrogen concentration was necessary for precisely designing optimized carbon materials. Abundance of nitrogen moieties aggravated the carbon corrosion. When the high potential was applied, specific types of graphitic N and pyridinic N were found to be favorable carbon modifications to improve carbon corrosion resistance. Moreover, the solvent effect was also investigated. The results provide theoretical insights and design guidelines to improve corrosion resistance in carbon support through material modification by inhibiting the adsorption of surface oxides (OH, O, and OOH). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The furfural hydrogenation mechanisms are systematically investigated in vapor phase and aqueous phase. • A proton-shuttling mechanism in aqueous phase is proposed. • The presence of water enhances the stability and activity of reaction intermediates. • The dynamic charge separation between the catalyst and the intermediates results in low hydrogenation barriers. The catalytic hydrogenation of biomass-derived compounds in the aqueous phase is crucial to upgrading renewable biochemicals and biofuels. Herein, by combining density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, we have explored the selective hydrogenation mechanism of furfural on the copper surface with a fully explicit solvation model. The presence of water solvent could significantly affect the reaction mechanism, in adjunct with the charge interactions between the reaction intermediates and the Cu surface. It demonstrates a proton-shuttling mechanism for furfural hydrogenation where the initial hydrogen source for reducing the carbonyl group is from the dissociation of the adjacent water. Furthermore, the water solvation effect results in the dynamic charge separation between the copper surface and the reaction intermediates, significantly reducing the energy barrier. These results deepen our mechanistic understanding of selective hydrogenation of furfural over Cu-catalysts, paving the way for upgrading renewable biomass derivatives in applications. [ABSTRACT FROM AUTHOR]

Designing a highly efficient electrocatalyst to realize overall water splitting is vital, yet identifying the active site remains an ongoing challenge. Herein, the electrochemical in situ surface activation of P@Co/Se 2 -NW/CC was investigated to understand the enhanced OER activity of P@Co/Se 2 -NW/CC. The incorporation of phosphorus is thought to increase the vacancies surrounding the Co cations in the initial Co/Se 2 and speed up the structural change into "active species" like cobalt oxide/oxyhydroxide. The as-synthesized P@Co/Se 2 -NW/CC required a low overpotential for OER (η 100 = 230 and 280 mV) and HER (η 100 = 111 and 132 mV), respectively, in alkaline water and alkaline seawater media. In-situ infrared reflection-absorption spectroscopy (IRRAS) and Post characterization unraveled the existence of surface-bounded Co oxide species on P@Co/Se 2 -NW/CC after OER catalysis, which is responsible for the enhanced electrocatalytic activity. This study offers a valuable strategy for developing noble-metal-free bifunctional catalysts for efficient hydrogen generation from alkaline seawater and alkaline water electrolysis. [Display omitted] • We successfully constructed a cost-efficient P@Co/Se 2 -NW heterointerface. • P@Co/Se 2 -NW heterointerface exhibits superior OER and HER catalytic performance in alkaline water and seawater electrolytes. • A symmetric alkaline water and seawater electrolyzer with a P@Co/Se 2 -NW electrode revealed enhanced performance. • Post characterization revealed surface-bounded Co oxide species on P@Co/Se 2 -NW/CC after OER catalysis. [ABSTRACT FROM AUTHOR]

We reported that the dissolved tungsten bronze (H x WO 3) exhibits the best activity for selective C C bond cleavage. The active species with low coordinated and low valent W site calls for the selectivity to C 2 fragments via a homolytic cleavage of C C bond cleavage. [Display omitted] • The formation of a chelated metalacyclic complex with 5-membered ring is critical for C C cleavage of glucose on the W-based catalyst. • The low-valent W center experiences a redox cycle (+V → +VI → +V) during the C C cleavage that accounts for the high reactivity of W-based catalyst. • The surface decoration of reduced and low-coordinated W site could be efficient for selective cellulose conversion in aqueous phase. In chemistry, selective activation of C C bonds enables the direct production of valuable chemicals from widely available and inexpensive natural materials but remains a fundamental challenge due to their kinetic inertness. The selective cleavage of C C bond in glucose by tungsten oxide-based catalysts in aqueous phase pioneers a path for converting cellulose biomass into valuable ethylene glycol. However, debates regarding the active phase and how it selectively breaks the C 6 into C 2 fragments have persisted for over a decade. In this study, we present a comprehensive mechanistic investigation by modeling three potential active phases, i.e. the reduced WO 3-x surface, the dissolved tungstic acid, and tungsten bronze, in explicit solvent waters. By constrained molecular dynamics simulations, we have demonstrated that the low-coordinated W center can chelate with glucose, forming a metallacyclic complex with a 5-membered ring after the protonation of carbonyl group. The formation of 5-membered ring serves as the premise for the selectivity to C 2 fragments via homolytic cleavage of C C bond. Furthermore, the reduced W5+ center is suggested to be crucial in facilitating the cleavage process by stabilizing the dissociated C 4 intermediates via a redox process. In conclusion, we propose that the surface decoration of reduced and low-coordinated W sites can act as active heterogeneous catalysts for the selective conversion of cellulose in aqueous phase. These recent findings have the potential to provide valuable insights and strategies for C C bond activation in both biomass conversion and organic synthesis. [ABSTRACT FROM AUTHOR]

The direct, nonoxidative conversion of methane on a silica‐confined single‐atom iron catalyst is a landmark discovery in catalysis, but the proposed gas‐phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe1©SiC2), followed by C−C coupling and hydrogen transfer to produce the main product (ethylene) via a key −CH−CH2 intermediate. We find a quasi Mars–van Krevelen (quasi‐MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe1©SiO2 and this surface process is identified to be more plausible than the alternative gas‐phase reaction mechanism. [ABSTRACT FROM AUTHOR]

The direct, nonoxidative conversion of methane on a silica‐confined single‐atom iron catalyst is a landmark discovery in catalysis, but the proposed gas‐phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe1©SiC2), followed by C−C coupling and hydrogen transfer to produce the main product (ethylene) via a key −CH−CH2 intermediate. We find a quasi Mars–van Krevelen (quasi‐MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe1©SiO2 and this surface process is identified to be more plausible than the alternative gas‐phase reaction mechanism. [ABSTRACT FROM AUTHOR]

• Co 3 O 4 nanorods and nanoparticles exhibit the same TOF value. • (110) is the main exposed lattice plane for both nanorods and nanoparticles. • Dissociation of surface O 2 * to form surface O* assisted by NO is the rate-determining step. • Surface nitrates and nitrites can be observed by FTIR techniques. Co 3 O 4 nanorods and nanoparticles were prepared and differed in the overall particle sizes and shapes, while in both cases the catalytically active (110) lattice plane was mainly exposed. The forward rate of NO oxidation of Co 3 O 4 nanorods, stated on catalyst weight, was higher than that of Co 3 O 4 nanoparticles. However, the turnover frequency (TOF) numbers normalized by the surface Co3+ were almost the same, indicating that NO oxidation took place over the same active sites of surface Co3+ for both catalysts. Co 3 O 4 nanorods had a larger number of exposed active sites than nanoparticles. The dissociation of surface O 2 *, formed by the quasi-equilibrated reaction of O 2 molecules on vacant sites (*), assisted by gaseous NO to form NO 2 and surface O*, was the rate-determining step in NO oxidation. In situ FTIR spectra confirmed that abundant bridged nitrates were formed on both Co 3 O 4 nanorods and nanoparticles. [ABSTRACT FROM AUTHOR]

This study presents an investigation into the steam reforming of hydrocarbons from biomass gasifier-derived syngas over MgAl 2 O 4 -supported transition metals (Ni, Rh, Ir, Ru, Pt, and Pd) and novel bimetallic IrNi catalysts. Using a model syngas consisting of H 2 , CO, CO 2 , CH 4 , C 2 H 4 , and H 2 O, Ir and Rh catalysts were found to be the most stable catalysts (at 850 °C, 1 bar, 114,000 h −1 ). When benzene and naphthalene are added to the feed (as a tar simulant) stability is affected by both tar concentration and type of tar. Catalytic deactivation, caused primarily by coking can be minimized by operating at a high reaction temperature (e.g., 850 °C). In addition, promoting Ni catalyst with Ir significantly enhances stability. By using bimetallic formulations of Ir and Ni (0.5–5.0% Ir, 15%Ni), nickel sintering during the reaction is reduced. Surprisingly, IrNi catalysts also offer more stability than catalysts with Ir particles alone. In agreement with theoretical calculations, small Ir° clusters (∼2–3 atoms) supported on large Ni° particles (≥5 nm) present more resistance to coking than either small Ir° clusters or Ni° particles alone. Hence, superior stability of the bimetallic catalysts results from both resistance to coking and a decrease in nickel sintering. Minimal loss of activity of 12% for TOS = 80 h is demonstrated for a bimetallic catalyst with optimal concentrations of 2.5% Ir and 15% Ni. Both monometallic Ir and Ni catalysts suffer substantial loss of activity (i.e., ≥40% loss, TOS = 80 h) under comparable conditions. [ABSTRACT FROM AUTHOR]

Developing single-atom photocatalysts for selective conversion of CO 2 to valuable fuel is of great attraction but remains challenging. In this work, ruthenium and copper single atoms are for the first time simultaneously incorporated into polymeric carbon nitride (PCN) through a simple preassembly-coprecipitation-pyrolysis process. The obtained PCN-RuCu sample exhibited much higher selectivity (95%) for CH 4 production than the individual Ru or Cu decorated PCN during photocatalytic CO 2 reduction under visible-light irradiation. The atomically dispersed Ru-N 4 and Cu-N 3 moieties were confirmed by spherical aberration-corrected electron microscopy and extended X-ray absorption fine structure spectroscopy. Density function theory (DFT) calculations revealed that the co-existence of Ru-N 4 sites and Cu-N 3 sites can effectively tune the electronic structure of PCN, making the Ru sites account for photogenerated electron-hole pairs and the Cu sites for CO 2 hydrogenation. Moreover, the synergetic effect between Ru and Cu single atoms significantly promotes the consecutive hydrogenation processes of *CO species towards CH 4 production. Our studies provide a new understanding of the mechanism for photocatalytic reduction of CO 2 to CH 4 , and pave a new way to design photocatalysts for the selective production of solar fuels. [Display omitted] ● Ru and Cu dual-metal-atom decorated PCN displayed high selectivity(95%) towards methane production in CO 2 photoreduction. ● The co-existence of Ru-N 4 sites and Cu-N 3 sites can effectively tune the electronic structure of PCN. ● The Ru sites account for photogenerated electron-hole pairs and the Cu sites for CO 2 hydrogenation ● Synergism between Ru and Cu single atoms significantly promotes the consecutive hydrogenation of *CO species towards CH 4. [ABSTRACT FROM AUTHOR]

• Computational chemistry is used to predict reactivity and mechanisms of pollutants. • Reactive sites of sulfonamides for chlorination locate on 4-aminobenzenesulfonmaide. • Product identification by LTQ-Orbitrap MS verifies the in silico prediction. • k obs can be predicted by free energy barriers via the Eyring-Polanyi equation. • Sulfonamides with stronger electron-donating heterocycle is easier to be chlorinated. Increasing number of emerging pollutants in environments requires an effective approach which can facilitate the prediction of reactivity and provide insights into the reaction mechanisms. Computational chemistry is exactly the tool to fulfill this demand with its good performance in theoretical investigation of chemical reactions at molecular level. In this study, chlorination of sulfonamide antibiotics is used as an illustration to present a systematic strategy demonstrating how computational chemistry can be applied to investigate the reaction behavior of emerging pollutants. Sulfonamides is a class of micropollutants that contain the common structure of 4-aminobenzenesulfonmaide while differ in their heterocycles. Based on the calculated conceptual DFT indices, the reactive sites of sulfonamide are successfully predicted, which locate on their common structure of 4-aminobenzenesulfonmaide. Therefore, all sulfonamides follow the similar reaction pathway. Product identification by LTQ-Orbitrap MS further verifies the in silico prediction. Three critical pathways are discovered, i.e., S-N bond cleavage, Cl-substitution onto aniline-N, and the following rearrangement to lose -SO 2 - group, among which Cl-substitution is the key step due to its lowest free energy barrier. Heterocycles impact the reaction rate by affecting the electronic density of aniline group. In general, the more electron-donating the heterocycle is, the more readily sulfonamides to be chlorinated. [Display omitted] [ABSTRACT FROM AUTHOR]

• Comparison on Zn/Cu, ZnO/Cu, and ZnOH/Cu surfaces as possible active phases. • Formate pathway is the dominant mechanism for CO 2 hydrogenation. • The surface hydroxyl can significantly increase the activity of CO 2 hydrogenation. The catalytical active phase and reaction mechanism of methanol synthesis by hydrogenation of carbon dioxide on the surface of Cu/ZnO/Al 2 O 3 catalyst become controversial topics in recent years. In this work, density functional theory calculations are employed to explore the possible mechanisms of the CO 2 hydrogenation on three possible active phases, namely Zn/Cu interface, ZnO/Cu interface and hydroxylated Zn/Cu surface (i.e., ZnOH/Cu), which may exist in Cu/ZnO/Al 2 O 3 catalyst under realistic conditions. It is more favorable that CO 2 activation takes place by the formate pathway rather than the Reverse Water-Gas Shift pathway. Furthermore, the surface hydroxyl group could significantly increase the activity of formate pathway by improving the hydrogenation steps of HCOO to HCOOH and H 3 CO to H 3 COH, which are usually deemed as the rate-determining steps. These results suggest that the ZnOH/Cu phase is not only the most stable but also the most active phase for CO 2 activation among Zn/Cu, ZnO/Cu and ZnOH/Cu, which could provide more insight into the design of highly efficient catalyst by tuning the surface active phase under operative conditions. [ABSTRACT FROM AUTHOR]