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Achieving fine control over the dispersion of supported platinum nanoparticles (Pt) is a promising avenue to enhancing their catalytic activity and selectivity. Experimental observations suggest that exposing ceria-supported Pt nanoparticles to O2at 500 °C promotes their dispersion into smaller particles and eventually single atoms. The exact role of oxygen in this process is not yet well understood. Past density functional theory studies of ceria-supported Pt have typically narrowed their scope to single atoms and clusters of a few atoms. Herein, we combine several approaches and types of models in a consistent atomistic framework to evaluate the relative stability of ceria-supported Pt as a function of the degree of oxidation of Pt and of the particle size, ranging from single atoms to nanoparticles 1.5 nm of diameter. We find that the largest nanoparticles remain the thermodynamically most stable species on the lowest energy facet of ceria even under oxidizing conditions, suggesting that stronger adsorption sites are required to stabilize smaller clusters and single atoms and promote oxidative dispersion.

Studying the chemical reactivity related to the solid electrolyte interphase (SEI) in lithium-ion batteries is challenging due to system heterogeneity (spatial and compositional). Semiempirical methods have the potential to reduce the computational cost compared to the computationally costly DFT computations. In this study, we have first assessed the performance of four semiempirical methods (GFN-xtb, GFN2-xtb, PM6-D3, and PM7-D3) to model major reactions for SEI formation and growth. We have included the decomposition reactions of the most used solvent (ethylene carbonate), most used salt (lithium hexafluorophosphate), and other electrolyte species like the co-solvent 1,3-dioxolane and the additive vinylene carbonate. We have found that PM7-D3 and GFN-xtb are the two best performing methods for the 32 tested reactions. Finally, we have performed PM7-D3 and GFN-xtb-based molecular dynamics for inorganic/organic interfaces. We have found that LiF is the most rigid salt, which barely reconstructs. In contrast, Li2O is subject to severe reconstruction at the GFN-xtb level of theory, but significantly less when using PM7-D3. Still, even at the PM7-D3 level of theory Li2O readily reacts with alkyl carbonates, leading to CO2dissociation and thus the formation of surface carbonates. When in contact with Li2O, ethylene carbonate can undergo partial dehydrogenation reactions and ring openings. This suggests that Li2O is overly reactive to be in direct contact with such organic molecules. Rather, it is surrounded by a passivating (mono)layer of Li2CO3. Indeed, our simulations suggest that for such a hybrid system (core of Li2O, shell of Li2CO3, solvated with ethylene carbonate) the organic solvent remains intact. Furthermore, for such a hybrid system GFN-xtb produces physically meaningful results, so that this method can be overall recommended.

In computational surface catalysis, the calculation of activation energies of chemical reactions is expensive, which, in many cases, limits our ability to understand complex reaction networks. Here, we present a universal, machine learning-based approach for the prediction of activation energies for reactions of C-, O-, and H-containing molecules on transition metal surfaces. We rely on generalized Bronsted–Evans–Polanyi relationships in combination with machine learning-based multiparameter regression techniques to train our model for reactions included in the University of Arizona Reaction database. In our best approach, we find a mean absolute error for activation energies within our test set of 0.14 eV if the reaction energy is known and 0.19 eV if the reaction energy is unknown. We expect that this methodology will often replace the explicit calculation of activation energies within surface catalysis when exploring large reaction networks or screening catalysts for desirable properties in the future.

Controlling the adsorption/desorption of molecules at the solid/water interface is central to a wide range of fields, from catalysis to batteries. For instance, adsorbing alcohols at the surface of γ-Al2O3can prevent its chemical weathering. To make sure that γ-Al2O3remains a stable catalyst support under operating conditions in liquid water, it is crucial to design alcohols that cannot desorb easily. Taking ethanol as a typical example, we here compare the adsorption/desorption mechanisms for two distinct adsorption modes of ethanol at the water/alumina interface using various density functional theory-based approaches. Thermodynamic integration (TI) simulations unambiguously identify ethoxy as the more stable adsorption mode. The presence of liquid water yields adsorption barriers of at least 20 kJ·mol−1. To better assess the effect of water, we perform three-dimensional well-tempered metadynamics simulations that include a bias accounting for solvation effects and proton transfers at the interface. Activating the proton shuffling allows us to explore a variety of protonation and hydration configurations and yields higher barriers (up to 40 kJ·mol–1) than the ones predicted by TI where the solvent reorganization was assumed to be decoupled from the desorption. This study illustrates the importance of explicitly treating solvation effects when modeling reactions at the solid/liquid interface.

We present the open-source python package DockOnSurf which automates the generation and optimization of low-energy adsorption configurations of molecules on extended surfaces and nanoparticles. DockOnSurf is especially geared toward handling polyfunctional flexible adsorbates. The use of this high-throughput workflow allows us to carry out the screening of adsorbate-surface configurations in a systematic, customizable, and traceable way, while keeping the focus on the chemically relevant structures. The screening strategy consists in splitting the exploration of the adsorbate-surface configurational space into chemically meaningful domains, that is, by choosing among different conformers to adsorb, surface adsorption sites, adsorbate anchoring points, and orientations and allowing dissociation of (acidic) protons. We demonstrate the performance of the main features based on varying examples, ranging from CO adsorption on a gold nanoparticle to sorbitol adsorption on hematite. Through the use of the presented program, we aim to foster efficiency, traceability, and ease of use in research within tribology, catalysis, nanoscience, and surface science in general.

Identifying the structure of the most active site is essential to improve the performance of supported metal catalysts. For structure-sensitive reactions, in silicodesign cannot be easily achieved combining the scaling relations and Brønsted–Evans–Polanyi relations, which are only built on energy-based descriptors. We used here the generalized coordination number as a structural descriptor and established that low-coordinated sites are desirable when using Co and Cu to perform the acceptor-less alcohol dehydrogenation reaction.

Cobalt nanorods and cobalt nanoplatelets, prepared by the same organometallic route with two different metal precursors, were tested for the first time in the acceptor-less dehydrogenation of 2-octanol. The nature of the metal precursor determines not only nanoparticle morphology but also their surface chemistry. While cobalt nanorods showed high conversions (up to 85% after 24 h) and complete selectivity toward 2-octanone with concomitant molecular hydrogen production, cobalt nanoplatelets were practically inactive. Here, we show that this striking difference in the catalytic properties is not associated with facet-dependent differences in reactivity, but rather with different surface chemistry. The activity critically depends on the coordinating ability of the adsorbed species under catalytic reaction conditions and to a smaller degree on their concentration, as evidenced by ligand exchange experiments at room temperature as well as by direct addition of ligands in the reaction during catalysis by cobalt nanorods. This study shows that to optimize performances with unsupported metal nanocatalysts, the capping ligands should be selected by considering their ability to reversibly dissociate from the metal surface during catalysis.

Despite progress in theoretical tools, the influence of solvation in heterogeneous catalysis remains poorly understood and predicted due to the large computational burden. In this work, we show that the inclusion of the solvation by water using a continuum model thermodynamically inhibits the O–H bond scissions involved in the ethanol aqueous phase reforming reaction over Pt(111), while it tends to favor the C–H, C–C, and C–O scissions. Then, we present a novel group additivity scheme for the free energy of adsorbates at the Pt/water interface that is able to capture this solvent effect. The mean absolute error (MeanAE) for the Gibbs free energy of formation is 3.3 kcal/mol over the investigated set of 200 species at the interface and the MeanAE for the 151 reaction free energies of ethanol aqueous phase reforming is 2.8 kcal/mol. Regarding the effect of solvation, our scheme is able to predict it with a MeanAE of about 1 kcal/mol. Together, the scheme promises to be accurate enough for narrowing down the most important reaction pathways in complex reaction networks as encountered in biomass conversion.

Modeling adsorption at metal/water interfaces is a cornerstone toward an improved understanding in a variety of fields from heterogeneous catalysis to corrosion. We propose and validate a hybrid scheme that combines the adsorption free energies obtained in the gas phase at the density functional theory level with the variation in solvation from the bulk phase to the interface evaluated using a MM-based alchemical transformation, denoted MMsolv. Using the GAL17 force field for the platinum/water interaction, we retrieve a qualitatively correct interaction energy of the water solvent at the interface. This interaction is of near chemisorption character and thus challenging, both for the alchemical transformation and also for the fixed point-charge electrostatics. Our scheme passes through a state characterized by a well-behaved physisorption potential for the Pt(111)/H2O interaction to converge the free energy difference. The workflow is implemented in the freely available SolvHybrid package. We first assess the adsorption of a water molecule at the Pt/water interface, which turns out to be a stringent test. The intrinsic error of our quantum-mechanical/molecular mechanics (QM/MM) hybrid scheme is limited to 6 kcal mol–1through the introduction of a correction term to attenuate the electrostatic interaction between near-chemisorbed water molecules and the underlying Pt atoms. Next, we show that the MMsolv solvation free energy of Pt (−0.46 J m–2) is in good agreement with the experimental estimate (−0.32 J m–2). Furthermore, we show that the entropy contribution at room temperature is roughly of equal magnitude as the free energy but with an opposite sign. Finally, we compute the adsorption energy of benzene and phenol at the Pt(111)/water interface, one of the rare systems for which experimental data are available. In qualitative agreement with the experiment, but in stark contrast with a standard implicit solvent model, the adsorption of these aromatic molecules is strongly reduced (i.e., less exothermic by ∼30 and 40 kcal mol–1for our QM/MM hybrid scheme and experiment, respectively, but ∼0 with the implicit solvent) at the solid/liquid interface compared to the solid/gas interface. This reduction occurs mainly because of the competition between the organic adsorbate and the solvent for adsorption on the metallic surface. The semiquantitative agreement with experimental estimates for the adsorption energy of aromatic molecules thus validates the soundness of our hybrid QM/MM scheme.

Understanding the structure of the water/metal interfaces plays an important role in many areas ranging from surface chemistry to environmental processes. The size, required phase-space sampling, and the slow diffusion of molecules at the water/metal interfaces motivate the development of accurate force fields. We develop and parametrize GAL19, a novel force field, to describe the interaction of water with two facets (111 and 100) of five metals (Pt, Pd, Au, Ag, Cu). To increase transferability compared to its predecessor GAL17, the water–metal interaction is described as a sum of pairwise terms. The interaction energy has three contributions: (i) physisorption is described via a Tang and Toennies potential, (ii) chemisorption and surface corrugation rely on an attractive Gaussian term, and (iii) the angular dependence is explicitly included as a truncated Fourier series. Thirteen parameters are used for each metal surface and were fitted on 250 water adsorption energies computed at the PBE+dDsC level. The performance of GAL19 was evaluated on a set of more than 600 DFT adsorption energies for each surface, leading to an average root-mean-square deviation of only 1 kcal/mol, correctly reproducing the adsorption trends: strong on Pt and Pd but weaker on Ag, Au, and Cu. This force field was then used to simulate the water/metal interface for all ten surfaces for 1 ns. Structural analyses reveal similar tendencies for all surfaces: a first, dense water layer that is mostly adsorbed on the metal top sites and a second layer up to around 6 Å, which is less structured. On Pt and Pd, the first layer is strongly organized with water lying flat on the surface. The pairwise additive functional form allows one to simulate the water adsorption on alloys, which is demonstrated at the example of Ag/Cu and Au/Pt alloys. The water/Ag–Cu interface is predicted to be disordered with water mostly adsorbed on Cu which should exacerbate the Ag reactivity. On the contrary, incorporating Pt into Au materials leads to a structuring of the water interface. Our promising results make GAL19 an ideal candidate to get representative sampling of complex metal/water interfaces as a first step toward accurate estimation of free energies of reactions in solution at the metal interface.

Alkaline-earth phosphates efficient in the dehydration of lactic acid to acrylic acid were previously shown to contain a surface mono/dihydrogen phosphate amorphous layer composed of M2+cations and both P═O and POH groups. In this work, acidic properties of such a layer were determined combining Fourier transform infrared (FTIR) spectra achieved at the dehydrated state and under water vapor and density functional theory (DFT) simulations of nondefective and defective MPOH structure. The FTIR spectra of adsorbed pyridine and lutidine revealed the presence of moderate Lewis acid sites (LAS) and of POH groups interacting by H-bonding without significant protonation. DFT calculations were key to interpret FTIR spectra after adsorption of NH3: when solely adsorbed, NH3interacts with the LAS on both the nondefective surface and the defective surface, whereas the POH for which H points up toward the gas phase are reoriented downward. Brønsted acid sites (BAS) were shown to form under water vapor. This phenomenon was shown by DFT to arise from a more acidic character of HPO42–species for the nondefective surface and casual formation of nondefective surface leading to higher amount of H2PO4–species, which are more acidic BAS.

Metal catalysts are essential in the production of fuels and chemicals. Nonetheless, tailoring the exposed active sites to achieve the maximal theoretical conversion is still a great challenge. In the case of structure-sensitive reactions, such as the attractive acceptor-less alcohol dehydrogenation, playing on the exposed metallic sites appears as an appealing strategy. Still, this approach requires advanced preparation protocols and is even more difficult to implement for supported non-noble metal catalysts which easily undergo sintering. Using the polyol method, we synthesized fourteen different cobalt catalysts, which consist of unsupported shaped nanoparticles stabilized by adsorbed carboxylate ligands. Their shape and the amount of ligands were characterized by combining TEM and TGA-N2measurements. These catalysts were found to be active in the 2-octanol dehydrogenation conditionally upon an organic layer limited to 1 to 2 monolayers. Moreover, they were fully selective towards the desired ketone and H2. The active catalysts were stable, with no leaching or modification of the shape during the reaction. Periodic DFT computations predict a greater activity of the pristine open-type facet than of the compact one, but this is not confirmed experimentally with no clear correlation between the activity expressed in turnover number and the amount of a given type of site as quantified by TEM. Further modeling including the organic layer shows that the presence of ligands reduces the sensitivity to the metallic structure. Nonetheless, these ligands generate a catalytic pocket, similar to the one found in enzymes, that interacts with the alcohol substrate through H-bonding. This pocket is the most adapted to the alcohol dehydrogenation on the open-type facet, which is mainly exposed on rods. This detailed understanding paves the way to an improved design of bespoke unsupported catalysts considering simultaneously the structure and the nature of the ligand.

Adsorption and desorption steps are key for active catalysts and rely on a subtle balance between enthalpic and entropic terms. While the enthalpic term is becoming ever more accurate through density functional development, the entropic term remains underrated and its precise determination a great challenge. In this work, we have performed extensive first-principles thermodynamic integration (TI) simulations for the adsorption of small (e.g., CO) to larger (e.g., phenol) molecules at metallic surfaces and compared their adsorption free energies to the values obtained by vertical, static statistical mechanics approximations to thermal corrections invoking three different approximations for the low-frequency modes. We have found an excellent agreement between the vertical corrections and the TI for minima, for both weakly bound systems (e.g., CO2and formic acid) and strongly chemisorbed molecules such as phenol or CO. While the treatment of the low-frequency modes has a minor impact on the agreement with TI, all vertical corrections systematically overestimate activation energies by 0.1–0.2 eV compared to TI, demonstrating a noticeable lowering of activation barriers. As a result of this study, we suggest that the vertical corrections and in particular the standard harmonic approximation can be safely applied to chemisorption minima, while the activation energies are likely to be overestimated. Hence, if a greater accuracy than ∼0.2 eV is required for activation free energies, we recommend to use thermodynamic integration, which for small- to medium-sized molecules in the gas phase is accessible with a reasonable computational effort but requires a dense sampling in the transition state region.

Numerous studies showed that, after adaptation to a leftward optical deviation, pseudoneglect behavior (overrepresentation of the left part compared to the right part of the space) becomes neglect-like behavior (overrepresentation of the right part compared to the left part of the space). Cognitive after-effects have also been shown in cognitive processes that are not intrinsically spatial in nature, but show spatial association as numbers or letters. The space-auditory frequency association (with low frequencies on the left and high frequencies on the right) raises the question of whether prism adaptation can produce after-effects on auditory perception. We used a new experimental protocol, named the ‘auditory interval bisection judgment’, where participants had to estimate what limit of an auditory interval (low or high) a target frequency was closer to. We calculated the subjective auditory interval center. In pretest, there was a spontaneous bias of the subjective center of the auditory interval toward the lower limit. That was the first demonstration of pseudoneglect behavior in auditory frequency representation. ANOVA realized on all participants did not show significant results of prism adaptation, but a posteriori analyses on musicians showed that, after adaptation to a leftward optical deviation, there were more target frequencies perceived as closer to the lower limit of the auditory interval. This result corroborates the shift of the subjective center of the auditory interval toward high frequency limit. These innovative results are discussed in terms of putative neural substrates underpinning the transfer of visuomotor plasticity to auditory frequency perception.

In electrochemical promotion of catalysis (EPOC), the adsorption energies of the reactants and products, and subsequently the overall catalytic reaction rate, are modified by applying an electrochemical potential to the catalyst. In this paper, the oxidation of ethylene on ruthenium oxide was studied through carrying out experiments and theoretical modeling in order to elucidate the atomistic origin of EPOC. The experimental results show an increase in the reaction rate under negative and positive polarization. The density functional theory (DFT)-based surface free energies demonstrate that there is an increase in oxygen coverage on the ruthenium surface as a function of the potential, conforming with the backspillover model of EPOC. Furthermore, the DFT results demonstrate that the positive polarization and the associated electric field, which increase the work function, result in enhanced adsorption and facilitate cleavage of the C–C bond of ethylene. Under negative polarization, on the other hand, it is the oxygen activation that is facilitated. Together, these two pieces of the puzzle explain the experimentally observed increase in the ethylene oxidation rate as a function of positive and negative potential, proving the effect of an electric field on the adsorption rate and activation energy of ethylene oxidation.

In alkene metathesis, while group 6 (Mo or W) high-oxidation state alkylidenes are accepted to be key reaction intermediates for both homogeneous and heterogeneous catalysts, it has been proposed that low valent species in their +4 oxidation state can serve as precatalysts. However, the activation mechanism for these latter species—generating alkylidenes—is still an open question. Here, we report the syntheses of tungsten(IV)–oxo bisalkoxide molecular complexes stabilized by pyridine ligands, WO(OR)2py3(R = CMe(CF3)2(2a), R = Si(OtBu)3(2b), and R = C(CF3)3(2c); py = pyridine), and show that upon activation with B(C6F5)3they display alkene metathesis activities comparable to W(VI)–oxo alkylidenes. The initiation mechanism is examined by kinetic, isotope labeling and computational studies. Experimental evidence reveals that the presence of an allylic CH group in the alkene reactant is crucial for initiating alkene metathesis. Deuterium labeling of the allylic C–H group shows a primary kinetic isotope effect on the rate of initiation. DFT calculations support the formation of an allyl hydride intermediate via activation of the allylic C–H bond and show that formation of the metallacyclobutane from the allyl “hydride” involves a proton transfer facilitated by the coordination of a Lewis acid (B(C6F5)3) and assisted by a Lewis base (pyridine). This proton transfer step is rate determining and yields the metathesis active species.

Formic acid can undergo dehydration or dehydrogenation with variable selectivity over a range of metal catalysts. The selectivity among these reactions depends on the reaction mechanism and reaction conditions pertinent on each surface. This work provides mechanistic insight into the decomposition of formic acid on cobalt at high- and low-temperature regimes. The adsorption and decomposition of formic acid on a Co(0001) single crystal was studied in ultrahigh vacuum by X-ray photoelectron spectroscopy and temperature-programmed desorption. Insight is provided using density functional theory calculations. In the low-temperature regime, formic acid adsorbs molecularly on the surface at 130 K. Partial decomposition produces CO at 140 K, and at 160 K, the decomposition of formic acid into formate, which is a thermodynamic sink, is dominant. Water can be formed at low temperature via bimolecular processes. At high temperature (>400 K), the similar barriers for decomposition of the formate species lead to the concomitant production of CO, CO2, and H2. The correlation between experiment and theory provides a framework for the interpretation of surface species and reaction path operating in different regimes.

Metal/water interfaces are key in many natural and industrial processes, such as corrosion, atmospheric, or environmental chemistry. Even today, the only practical approach to simulate large interfaces between a metal and water is to perform force-field simulations. In this work, we propose a novel force field, GAL17, to describe the interaction of water and a Pt(111) surface. GAL17 builds on three terms: (i) a standard Lennard-Jones potential for the bonding interaction between the surface and water, (ii) a Gaussian term to improve the surface corrugation, and (iii) two terms describing the angular dependence of the interaction energy. The 12 parameters of this force field are fitted against a set of 210 adsorption geometries of water on Pt(111). The performance of GAL17 is compared to several other approaches that have not been validated against extensive first-principles computations yet. Their respective accuracy is evaluated on an extended set of 802 adsorption geometries of H2O on Pt(111), 52 geometries derived from icelike layers, and an MD simulation of an interface between a c(4 × 6) Pt(111) surface and a water layer of 14 Å thickness. The newly developed GAL17 force field provides a significant improvement over previously existing force fields for Pt(111)/H2O interactions. Its well-balanced performance suggests that it is an ideal candidate to generate relevant geometries for the metal/water interface, paving the way to a representative sampling of the equilibrium distribution at the interface and to predict solvation free energies at the solid/liquid interface.

The ever-growing development of biomass-based chemicals calls for a better understanding of the specificities of the corresponding catalytic processes. In this quest, ab initiomodeling is a corner-stone that has proven its ability to rationalize the observed trends and then to propose novel catalysts design. Focusing on supported metal catalysts, we show that computational studies started a decade ago with alcohols and small polyols transformation, focusing on activity but also selectivity. Little by little, their scope has been extended to a variety of cellulosic-based chemicals such as levulinic acid or furanic molecules. During the last two years, it has also started to embrace lignin-derived chemicals, such as anisole, guaiacol, etc. Parallel to this scope expansion, the available methodologies have also progressed, triggered by the intrinsic difficulties of modeling biomass valorisation. In particular, improving the inclusion of the water solvent has drawn several groups to propose novel approaches.

The direct amination of alcohols by ammonia is a promising sustainable route to primary amines. The development of novel heterogeneous catalysts calls for a better understanding of this reaction. Through a combination of well-designed catalytic tests and periodic DFT computations, we provide here a deeper understanding of the factors determining the activity of Ni and Pd catalysts. In particular, we demonstrate that a proper assessment of the relative activity requires the inclusion of a spectator species, namely ammonia, which modifies the rate limiting intermediate and transition state and thus affects the overall predicted activity. This better understanding paves the road for a rational improvement of metal-based catalysts.

Oxidation of alcohols is a key-reaction for the valorization of biomass compounds, and green processes are preferred to avoid the use or production of toxic compounds. In this context, unsupported nanometer-sized catalysts have emerged as very promising materials for heterogeneous catalysis. In this paper we explore the catalytic activity of unsupported cobalt nanoparticles towards the dehydrogenation of aliphatic primary and secondary alcohols under solvent-free conditions. The unsupported particles are found to be highly active for the conversion of secondary alcohol to the corresponding ketone vs.the primary alcohol. The oxidation process is following an acceptorless dehydrogenation mechanism, where the only by-product of the reaction is the highly valuable H2molecule. DFT calculations evidence that the chemoselectivity of secondary vs.primary alcohols originates from a more favorable desorption of the ketone reaction product compared to the aldehyde. It is also found that the morphology of the particles has a strong influence on the catalyst efficiency and stability: Co nanorods can be recycled at least three times without a loss in catalytic performances.

Gamma-valerolactone (GVL) is one of the key products of future biorefineries. We show here for the first time the superior activity of Ni-based, Au doped catalysts in levulinic acid hydrogenation towards GVL using formic acid as a hydrogen source. Their performances are strongly influenced by the preparation method, and the highest GVL yield is achieved for bimetallic Au–Ni catalysts prepared viaco-impregnation of both metallic salts with a reductive thermal treatment under hydrogen. The very high catalytic activity is explained by the use of DFT calculations and the extensive characterization of the catalyst surface and bulk properties. We highlight the pivotal role played by the incorporated isolated metallic Ni atoms within Au nanoparticles. The nano-alloy composition is determined. It allows establishment of a surface model of such an alloy, thanks to which the high activity can be explained by the presence of an optimum energetic span of FA adsorption. The existence of strong interaction between Au and Ni in a surface alloy, Au–Ni, favors selective and fast decomposition of formic acid into hydrogen that consequently facilitates strongly the combined hydrogenation process.

To sustain the current attempts in valorizing lignin-based derivatives, this study focuses on the decomposition upon a temperature ramp of 2-phenoxyethanol, a model for the β-O-4 linkage in lignin, on a Pt(111) surface. Under ultrahigh-vacuum conditions, benzene, hydrogen, and carbon monoxide are the main desorbing products. Although benzene is the only aromatic desorbed product at low initial molecular coverages, very small amounts of phenol can be detected at higher initial coverage. Combining X-ray photoelectron spectroscopy and temperature-programmed desorption experiments together with density functional theory calculations, a reaction mechanism is suggested, starting with the OH bond scission. Phenoxy, PhO, is proposed as a key surface intermediate that preferentially deoxygenates rather than desorbs as phenol, similarly to the case of anisole. This behavior, typical of ultrahigh-vacuum conditions, is attributed to the reducing properties of carbonaceous surface species that efficiently deoxygenate phenoxy and afford the formation of the very stable carbon monoxide.

The adsorption of CO on Pd nanoparticles (NP) supported on MgO ultrathin films is studied by sum frequency generation (SFG) vibrational spectroscopy at room temperature as a function of CO coverage for NP lateral sizes ranging from 3 to 6 nm. While the spectroscopic signature of CO on (100) top facets dominates the spectra, other new bands are attributed to (111) facets, edges, and defects. CO remains strongly bonded for all sizes, but spectroscopic and kinetic parameters evolve as NP size decreases. It is only for the smallest NPs ∼3 nm in diameter that the deviation from Pd(100) single crystal is important. Modeling of adsorption kinetics, dipolar coupling and DFT calculations allow rationalizing the observations: the size dependent Pd–Pd bond extension by the substrate is the main parameter that controls CO frequency in the low coverage limit. SFG sensitivity is found to increase up to 10–4ML as NP size decreases. This makes SFG particularly well suited to probe molecular adsorption in the submonolayer range on small NPs of 3 nm in diameter and below. These results motivate one to probe CO under catalytic conditions and to follow electron transfer in pump–probe experiments.

To sustain the development of novel metal-supported catalysts for transformation of polyalcohol molecules in silico, the development of efficient and accurate linear relationships to predict activation energies represents a major milestone. We establish here Brønsted–Evans–Polanyi relationships for CH and OH cleavages in monoalcohol molecules H-bonded with a chemisorbed water molecule over a series of transition metal surfaces. Then, we demonstrate that these relations can be used to predict glycerol and 1,2-propanediol dehydrogenation over Rh with remarkable accuracy and almost no systematic deviation. Lastly, we discuss the conditions to use these relations safely for screening dense catalytic reaction networks on different metallic surfaces.

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To screen heterogeneous catalysts in silico, the linear energy relationships derived from the Brønsted–Evans–Polanyi principle are extremely useful. They connect the reaction energy of a given elementary step to its activation energy, hence providing data that can be fed to kinetics models at a minimal cost. However, to ensure reasonable predictions, it is essential to control the statistical error intrinsic to this approach. We derived several types of linear energy relations for a series of CH and OH bond scissions in simple alcohol molecules on compact facets of seven transition metals (Co, Ni, Ru, Rh, Pd, Ir, and Pt) aiming at a single but accurate relation. The quality of the relation depends on its nature and/or on the manner the data are split: a single linear relation can be constructed for all metals together on the basis of the original Brønsted–Evans–Polanyi formulation with a mean absolute error smaller than 0.1 eV, whereas the more recent transition state scaling approach requires considering each metal individually to reach an equivalent accuracy. In addition, a close statistical analysis demonstrates that errors stemming from such predictive models are not uniform along the set of metals and of chemical reactions that is considered opening the road to a better control of error propagation.

This paper critically evaluates the state of the art in combined quantum mechanical/molecular mechanical (QM/MM) approaches to the computational description of chemistry in water and supplies guidelines for the setup of customized multiscale simulations of aqueous processes. We differentiate between structural and dynamic performance, since some tasks, e.g., the reproduction of NMR or UV–vis spectra, require only structural accuracy, while others, i.e., reaction mechanisms, require accurate dynamic data as well. As a model system for aqueous solutions in general, the approaches were tested on a QM water cluster in an environment of MM water molecules. The key difficulty is the description of the possible diffusion of QM molecules into the MM region and vice versa. The flexible inner region ensemble separator (FIRES) approach constrains QM solvent molecules within an active (QM) region. Sorted adaptive partitioning (SAP), difference-based adaptive solvation (DAS), and buffered-force (BF) are all adaptive approaches that use a buffer zone in which solvent molecules gradually adapt from QM to MM (or vice versa). The costs of SAP and DAS are relatively high, while BF is fast but sacrifices conservation of both energy and momentum. Simulations in the limit of an infinitely small buffer zone, where DAS and SAP become equivalent, are discussed as well and referred to as ABRUPT. The best structural accuracy is obtained with DAS, BF, and ABRUPT, all three of similar quality. FIRES performs very well for dynamic properties localized deep within the QM region. By means of elimination DAS emerges as the best overall compromise between structural and dynamic performance. Eliminating the buffer zone (ABRUPT) improves efficiency and still leads to surprisingly good results. While none of the many new flavors are perfect, all together this new field already allows accurate description of a wide range of structural and dynamic properties of aqueous solutions.

The prediction of our actions and their interaction with the external environment is critical for sensorimotor adaptation. For instance, during prism exposure, which deviates laterally our visual field, we progressively correct movement errors by combining sensory feedback with forward model sensory predictions. However, very often we project our actions to the external environment without physically interacting with it (e.g., mental actions). An intriguing question is whether adaptation will occur if we imagine, instead of executing, an arm movement while wearing prisms. Here, we investigated prism adaptation during mental actions. In the first experiment, participants (n = 54) performed arm pointing movements before and after exposure to the optical device. They were equally divided into six groups according to prism exposure: Prisms-Active, Prisms-Imagery, Prisms-Stationary, Prisms-Stationary-Attention, No Conflict-Prisms-Imagery, No Prisms-Imagery. Adaptation, measured by the difference in pointing errors between pre-test and post-test, occurred only in Prisms-Active and Prisms-Imagery conditions. The second experiment confirmed the results of the first experiment and further showed that sensorimotor adaptation was mainly due to proprioceptive realignment in both Prisms-Active (n = 10) and Prisms-Imagery (n = 10) groups. In both experiments adaptation was greater following actual than imagined pointing movements. The present results are the first demonstration of prism adaptation by mental practice under prism exposure and they are discussed in terms of internal forward models and sensorimotor plasticity.

In the aerobic selective oxidation of alcohols in aqueous medium in a batch reactor, it was observed that the addition of water to dioxane solvent (10–50 vol%) substantially increased the activity of a Pt/C catalyst. Periodic density functional theory (DFT) calculations were carried out to compare the reactivity of alcohols on the bare Pt(111) surface and in the presence of adsorbed water or hydroxyl groups, to explain the effect of water. The calculations indicate that the presence of adsorbed hydroxyl groups promotes the catalytic activity by participating directly in the catalytic pathways and reducing the activation barrier. Good agreement was found between the experiments in aqueous phase and these calculations. Further, decarbonylation of the aldehyde may be involved in the deactivation during oxidation of a primary alcohol.

We report herein a detailed and accurate study of the mechanism of rhodium‐catalysed conversion of glycerol into 1,2‐propanediol and lactic acid. The first step of the reaction is particularly debated, as it can be either dehydration or dehydrogenation. It is expected that these elementary reactions can be influenced by pH variations and by the nature of the gas phase. These parameters were consequently investigated experimentally. On the other hand, there was a lack of knowledge about the behaviour of glycerol at the surface of the metallic catalyst. A theoretical approach on a model Rh(111) surface was thus implemented in the framework of density functional theory (DFT) to describe the above‐mentioned elementary reactions and to calculate the corresponding transition states. The combination of experiment and theory shows that the dehydrogenation into glyceraldehyde is the first step for the glycerol transformation on the Rh/C catalyst in basic media under He or H2atmosphere.

This study compared the visuospatial asymmetries in children with dyslexia and healthy children by using the manual line bisection task, and investigated the processing of spatial context with a ‘local’ cueing paradigm consisting of geometric symbols placed on the extremities of the lines. The performance between healthy children (leftward bias) and children with dyslexia (rightward bias) was significantly different. Furthermore, the bisection mark wasshifted in the direction of the unilaterally cued extremities in all children. As children with dyslexia showeda rightward bias in their spatial representation, which did not interfere with local context processing, weproposed the term ‘inverse pseudoneglect’ to depict their behaviour in line bisection.

By using metadynamics at a temperature T0we reconstruct the free energy FT0(E,s) as a function of the potential energy Eand of a geometrical variable s. We show here that from FT0(E,s) one can estimate the free energy also at a different temperature. This allows tracing the entropy and characterizing the properties of molecular systems at all temperatures by a single simulation. We validate this approach on the water dimer dissociation.

Dinuclear zinc(II) complexes [Zn2(bpmp)(μ‐OH)](ClO4)2(1) and [Zn2(bpmp)(H2O)2](ClO4)3(2) (H‐BPMP=2,6‐bis[bis(2‐pyridylmethyl)aminomethyl]‐4‐methylphenol) have been synthesized, structurally characterized, and pH‐driven changes in metal coordination observed. The transesterification reaction of 2‐hydroxypropyl p‐nitrophenyl phosphate (HPNP) in the presence of the two complexes was studied both in a water/DMSO (70:30) mixture and in DMSO. Complex 2was not reactive whereas for 1considerable rate enhancement of the spontaneous hydrolysis reaction was observed. A detailed mechanistic investigation by kinetic studies, spectroscopic measurements (1H, 31P NMR spectroscopy), and ESI‐MS analysis in conjunction with ab initio calculations was performed on 1. Based on these results, two medium‐dependent mechanisms are presented and an unusual bridging phosphate intermediate is proposed for the process in DMSO.

An efficient and versatile tandem process of acetalization and cycloisomerization reactions has been developed for the reactions of 1‐alkynyl‐2‐carbonylquinoline substrates. The reaction occurs thanks to AuIand AgIcatalysis. Silver(I) catalysis has been extensively studied (11 different silver species) on a broad range of quinoline derivatives (variation of alkyne substituent, of carbonyl function and of nucleophiles), leading to a variety of furoquinoline and pyranoquinoline moieties. An insight is given for the presumed mechanism along with DFT‐B3 LYP/6–31G** calculations to address the 6‐endoand 5‐exoregioselectivities observed.

Organic/oxide interfaces play an important role in many areas of chemistry and in particular for lubrication and corrosion. Molecular dynamics simulations are the method of choice for providing complementary insight to experiments. However, the force fields used to simulate the interaction between molecules and oxide surfaces tend to capture only weak physisorption interactions, discarding the stabilizing Lewis acid/base interactions. We here propose a simple complement to the straightforward molecular mechanics description based on “out-of-the-box” Lennard-Jones potentials and electrostatic interactions: the addition of an attractive Gaussian potential between reactive sites of the surface and heteroatoms of adsorbed organic molecules, leading to the Gaussian Lennard-Jones (GLJ) potential. The interactions of four oxygenated and four amine molecules with the typical and widespread hematite and γ-alumina surfaces are investigated. The root mean square deviation (RMSD) for all probed molecules is only 5.7 kcal/mol, which corresponds to an error of 23% over hematite. On γ-alumina, the RMSD is 11.2 kcal/mol using a single parameter for all five chemically inequivalent surface aluminum atoms. Applying GLJ to the simulation of organic films on oxide surfaces demonstrates that the mobility of the surfactants is overestimated by the simplistic LJ potential, while GLJ and other qualitatively correct potentials show a strong structuration and slow dynamics of the surface films, as could be expected from the first-principles adsorption energies for model head groups.