Supported nanoparticle catalysts are widely used in the chemical industry. Computational modeling of supported nanoparticles based on density functional theory (DFT) often involves structural searches of stable local minimum energy configurations and molecular dynamics simulations at finite temperature. These are computationally demanding tasks that are intractable within DFT for large systems. In the last two decades, machine learning interatomic potentials (MLIPs) have been successfully used to substantially increase the size and time scales accessible to simulations approximating DFT accuracy. However, training reliable MLIPs is non-trivial as it requires many costly DFT calculations. Recently, several universal MLIPs (uMLIPs) have been developed, which are trained on large datasets that cover a wide range of molecules and materials. Here, we benchmark the accuracy and the efficiency of these uMLIPs in describing Cu nanoparticles supported on Al2O3 surfaces against our domain-specific DP-UniAlCu model. We find that the MACE-OMAT can reproduce reasonably well the low-energy structures found in global optimization at an energy accuracy comparable to DP-UniAlCu. Interestingly, the MatterSim-v1.0.0-1M model, which exhibits larger deviations in the binding energies, can find even more stable configurations than the other two models in some supported nanoparticle sizes, showing its capability in structure exploration. For MD simulations, MACE-OMAT and MatterSim-v1.0.0-1M can qualitatively reproduce the mean-squared displacements of Cu atoms (MSDCu) predicted by DP-UniAlCu, albeit at roughly two orders of magnitude higher cost. We demonstrate that the uMLIPs can be very useful in simulating supported nanoparticles even without any fine-tuning, though their reduced efficiency remains a limiting factor for large-scale simulations.

Understanding the nature of catalytic active sites under reaction conditions remains a central challenge in heterogeneous catalysis. In industrial copper/zinc oxide/alumina catalysts for methanol synthesis, small Zn-based species at the Cu interface have long been proposed as active-site candidates, yet their atomic-scale structure and stability remain controversial. Computational studies typically identify such species from optimized 0 K structures, assuming that minimum-energy configurations remain representative under reaction conditions. Here, we combine machine-learning-interatomic-potential-accelerated global optimization, molecular dynamics, and enhanced-sampling free-energy calculations to investigate supported Zn_3(OH)_3 and Zn_3(OH)_2CHOO clusters on Cu(111)-based surfaces from 0 to 450 K. While compact triangular configurations are generally favored among minimum-energy structures at 0 K, finite-temperature free-energy calculations reveal a pronounced shift toward extended linear configurations with increasing temperature. This transition is driven primarily by entropic stabilization and cannot be inferred from potential energies alone. Molecular dynamics further shows substantial cluster mobility on pristine Cu(111), indicating that long-term persistence depends not only on configurational stability but also on surface mobility. Surface Zn alloying strongly suppresses diffusion, thereby stabilizing isolated interfacial Zn species. Together, these results show that thermodynamically relevant structures of supported Zn-based clusters can differ fundamentally from static 0 K predictions because of competing enthalpic and entropic effects. Our findings highlight the limitations of identifying catalytic active sites solely from 0 K structures and underscore the importance of explicit finite-temperature sampling in catalyst modeling.

Understanding the atomic-scale structure and dynamics of amorphous oxide surfaces is essential for interpreting their chemical reactivity, mechanical stability, and interfacial behavior, yet direct experimental characterization remains challenging. We employ Deep Potential (DP) molecular dynamics to generate large-scale, ab initio-quality models of amorphous Al2O3 bulk glasses and melt-quenched free surfaces, enabling a quantitative analysis of both structure and relaxation dynamics with statistical confidence inaccessible to direct ab initio simulation. The trained DP model reproduces experimental liquid and glass structure, captures the cooling-rate dependence of the bulk glass transition, and corrects systematic biases in the polyhedral populations predicted by widely used classical force fields. At the free surface, mass density recovers to bulk values over ∼10 Å, while local coordination requires a slightly wider subsurface region to fully converge. The outermost layer is oxygen-enriched, exhibits altered polyhedral connectivity with contracted AlO bonds, and hosts a broad population of under-coordinated motifs (notably AlO3 and OAl2) whose abundances are governed by glass stability. These under-coordinated surface motifs exhibit distinct vibrational signatures and occur as locally paired Lewis acid and Brønsted base sites consistent with bond-valence compensation, yet remain spatially dispersed rather than aggregating into extended clusters. Despite this pronounced structural heterogeneity, surface relaxation and the glass-transition temperature remain comparable to their bulk counterparts, suggesting that the disordered surface is kinetically stable once formed. Together, these results establish a molecular-level picture of amorphous alumina surfaces and demonstrate the capability of machine-learned potentials to resolve structure–property relationships in disordered oxide interfaces.

Nanoparticle sintering remains a critical challenge in heterogeneous catalysis. In this work, we present a unified deep potential (DP) model based on the Perdew-Burke-Ernzerhof approximation of density functional theory for Cu nanoparticles on three Al2O3 surfaces (γ-Al2O3(100), γ-Al2O3(110), and α-Al2O3(0001)). Using DP-accelerated simulations, we reveal that the nanoparticle size-mobility relationship strongly depends on the supporting surface. The diffusion of nanoparticles on the two γ-Al2O3 surfaces is almost independent of the size of the nanoparticle, while the diffusion on α-Al2O3(0001) decreases rapidly with increasing size. Interestingly, nanoparticles with fewer than 55 atoms diffuse several times faster on α-Al2O3(0001) than on γ-Al2O3(100) at 800 K while expected to be more sluggish based on their larger binding energy at 0 K. The diffusion on α-Al2O3(0001) is facilitated by dynamic metal-support interaction (MSI), where Al atoms move out of the surface plane to optimize contact with the nanoparticle and relax back to the plane as the nanoparticle moves away. In contrast, the MSI on γ-Al2O3(100) and on γ-Al2O3(110) is dominated by more stable and directional Cu-O bonds, consistent with the limited diffusion observed on these surfaces. Our extended MD simulations provide insight into the sintering processes, showing that the dispersity of the nanoparticles strongly influences the coalescence driven by nanoparticle diffusion. We observed that the coalescence of Cu13 nanoparticles on α-Al2O3(0001) can occur in a short time (10 ns) at 800 K even with an initial internanoparticle distance increased to 3 nm, while the coalescence on the two γ-Al2O3 surfaces are inhibited significantly by increasing the initial internanoparticle distance. These findings demonstrate that the dynamics of the supporting surface is crucial to understanding the sintering mechanism and offer guidance for designing sinter-resistant catalysts by engineering the support morphology.

We computationally investigate the catalytic potential of MoSe$_2$, WS$_2$, and WSe$_2$ nanoribbons and nanosheets for the partial hydrogenation of CO$_2$ to methanol by comparing their electronic, adsorption, and defect properties to MoS$_2$, a known thermo-catalyst. We identify Se-deficient MoSe$_2$ (followed by WSe$_2$) nanosheets to be favorable for selective methanol formation.

In this work, we present a Pt decorated ZnO thin film-based gas sensor for hydrogen detection, fabricated using a sputtering technique and an in-situ Pt decoration approach. Specifically, we deposit a ZnO thin film on an interdigitated electrode substrate, with Pt nanoclusters added to the (002) polar plane by brief sputtering (1 to 6 s) to create an active sensing interface. Our sensor demonstrates optimal performance at an operating temperature of 498 K, with rapid response and recovery times (10 and 3 s), high selectivity, and long-term stability. We find the Pt decorated ZnO sensor, with a Pt deposition time of 2 s, to exhibit enhanced response ( 52,987

In this work, we present a Pt nanocluster-decorated ZnO thin film-based gas sensor for hydrogen detection, fabricated using the sputtering technique and in situ Pt decoration. The sensor exhibits a stable, highly sensitive, and repeatable response, making it a promising candidate for safety monitoring in hydrogen storage and transportation. Our sensor demonstrates optimal performance at an operating temperature of 225 degrees C with rapid response and recovery times (similar to 10 and 3 s), high selectivity, and long-term stability. We deposit the ZnO thin film on an interdigitated electrode (IDE) substrate, with Pt added to the (002) polar plane by brief sputtering (1 to 6 s) to create an active sensing interface. We find that the Pt nanocluster-decorated ZnO sensor, with a deposition time of 2 s exhibits an enhanced response (similar to 52,987%) to 1% hydrogen concentration, indicating its suitability for industrial applications. Our device demonstrates reliable detection of low hydrogen concentrations (similar to 100 ppb), with a response of similar to 38% and no response drift over 1 year of testing, making it useful for environmental monitoring. To elucidate the role of Pt on ZnO for hydrogen sensing, we performed density functional theory calculations, analyzing adsorption and reaction energetics involving adsorbed H2, O2, O, OH, and H2O, as well as lattice oxygen atoms on the ZnO (002) surface with and without Pt decoration. Our computational data is in agreement with experimental observations, identifying the oxygen-exposed (002) surface to be the most active for hydrogen sensing in both pristine and Pt nanocluster-decorated ZnO. Further, our computations highlight the role of Pt in enhancing hydrogen sensitivity via i) activating the autoreduction pathway of adsorbed hydroxide species, ii) spontaneous dissociation of adsorbed molecular hydrogen, and iii) keeping the lattice oxygen pathway of forming water active. Our systematic approach of designing sensors, combining a robust experimental setup with theoretical insights, is key in developing efficient hydrogen sensors, as well as in understanding the mechanisms behind such superior performance.

Ethylene dimerization is an efficient industrial chemical process to produce 1‐butene, with demanding selectivity and activity requirements on new catalytic systems. Herein, a series of monodentate phosphinoamine‐nickel complexes immobilized on UiO‐66 are described for ethylene dimerization. These catalysts display extensive molecular tunability of the ligand similar to organometallic catalysis, while maintaining the high stability attributed to the metal–organic framework (MOF) scaffold. The highly flexible postsynthetic modification method enables this study to prepare MOFs functionalized with five different substituted phosphines and 3 N‐containing ligands and identify the optimal catalyst UiO‐66‐L5‐NiCl2 with isopropyl substituted nickel mono‐phosphinoamine complex. This catalyst shows a remarkable activity and selectivity with a TOF of 29 000 (molethyl/molNi/h) and 99% selectivity for 1‐butene under ethylene pressure of 15 bar. The catalyst is also applicable for continuous production in the packed column micro‐reactor with a TON of 72 000 (molethyl/molNi). The mechanistic insight for the ethylene oligomerization has been examined by density functional theory (DFT) calculations. The calculated energy profiles for homogeneous complexes and truncated MOF models reveal varying rate‐determining step as β‐hydrogen elimination and migratory insertion, respectively. The activation barrier of UiO‐66‐L5‐NiCl2 is lower than other systems, possibly due to the restriction effect caused by clusters and ligands. A comprehensive analysis of the structural parameters of catalysts shows that the cone angle as steric descriptor and butene desorption energy as thermodynamic descriptor can be applied to estimate the reactivity turnover frequency (TOF) with the optimum for UiO‐66‐L5‐NiCl2. This work represents the systematic optimization of ligand effect through combination of experimental and theoretical data and presents a proof‐of‐concept for ethylene dimerization catalyst through simple heterogenization of organometallic catalyst on MOF.

Using DFT, we demonstrate external electric field assisted CO 2 capture on different MgO facets, leading to carbonate formation in strongly adsorbed cases, and in some cases even CO 2 reduction to CO on polar MgO(111) facet.

The active and selective electrochemical reduction of CO2 to value-added chemical intermediates can offer a sustainable route for the conversion of CO2 to chemicals and fuels, thus helping to mitigate greenhouse gas emissions and enabling intermittent energy from renewable sources. Alkaline solutions are often the preferred media for the electrocatalytic CO2 reduction reaction (CO2RR) as they provide high current densities and low overpotentials while suppressing the hydrogen evolution side reaction. Recent experiments carried out on Au and Ag in KOH, as well as other electrolytes, including KHCO3, K2CO3, and KCl, showed that increasing electrolyte concentration lowered onset potentials, increased Faradaic efficiencies to CO, and improved current densities. Herein, we carry out potential-dependent ab initio molecular dynamic (AIMD) simulations along with density functional theory (DFT) calculations using explicit KOH electrolyte and H2O solution molecules to examine the influence of OH- anions and the KOH electrolyte on the elementary steps and their corresponding energetics in the mechanism for CO2 reduction. The simulations indicate that the first electron transfer step to CO2 to form the adsorbed *CO2(center dot-) radical anion is rate-limiting, while the subsequent proton and electron transfer steps are facile and downhill in energy at reducing potentials. The OH- anions present in the solution can adsorb on the Au cathode down to potentials as low as similar to -3 V (SCE). This enables the OH- anions to transfer electrons to the Au cathode and into antibonding 2 pi* orbitals of CO2, thus facilitating the rate-determining adsorption and electron transfer to CO2 to form the adsorbed *CO2(center dot-) radical anion. Increasing the concentration of the K+OH- electrolyte reduces the barrier for the electrocatalytic reduction of CO2 and thus improves the current density, consistent with the reported experimental results. The *CO2(center dot-) radical anion that forms subsequently undergoes facile proton transfer from a vicinal water molecule in solution to form the hydroxy carbonyl (*HOCO) intermediate that readily undergoes subsequent proton and electron transfer from a second water molecule to form CO and OH- at a potential of similar to -1.2 V SCE. While the formation of formate (HCOO-) is thermodynamically favorable, the direct hydrogenation of *CO2(center dot-) as well as the intramolecular proton transfer via *HOCO to form HCOO- are kinetically unfavored. The presence of OH- anions near the surface also facilitates the formation of bicarbonate (HCO3-) at lower potentials. The bicarbonate that forms can be converted to the reactive *HOCO intermediate at more negative potentials that subsequently reacts to form CO and regenerate OH-. The results discussed herein help provide a more detailed understanding of the interplay between the OH-, K+, H2O, and reaction intermediates on the Au surface in the electric double layer and their influence on the onset potential, electrocatalytic activity, and selectivity for CO2RR.

One of the most challenging topics in heterogeneous catalysis is conversion of CH4 to higher hydrocarbons. Direct conversion of CH4 to ethylene can be achieved via the oxidative coupling of methane (OCM) reaction. Despite studies which have shown MgO to activate CH4 and initiate the OCM reaction, its large-scale applications face a significant impediment due to formation of a byproduct, CO2, and poisoning of the catalyst due to carbonate formation. In the present work, we address two aspects of the OCM reaction on MgO surfaces: carbonate formation on the surface of the catalyst, and (dissociative) adsorption of CH4. We use first-principles density functional theoretical calculations to determine the energetics and underlying mechanisms of interaction of CO2 and CH4 with various surfaces of MgO: (100), (110), and (111) (both Mg- and O-terminations), and the seldom studied, hydroxylated (111) MgO surface with O-termination. We find that the strength of the interaction of CO2 with MgO surfaces depends on several factors: their surface energies, coordination number of surface O atoms, and ability to donate electrons. However, the O-terminated (111) surface of MgO bucks all aforementioned factors, with only oxygen richness affecting its reactivity towards CO2. The interaction of CH4 with MgO surfaces depends primarily on the coordination number of the surface O atoms and the orientation of the CH4 molecule with respect to the surface. Finally, we provide insights into (a) formation of surface carbonates, which is relevant to CO2 capture and conversion, and (b) C-H bond activation on MgO surfaces, which is crucial for direct conversion of CH4 to value-added chemicals.

The carbon deposition and permeation on nickel surfaces were investigated from thermodynamic and kinetic aspects by using density functional theory (DFT), ab initio atomic thermodynamics, and classical molecular dynamics (MD) simulations. The resulting evolution of particle morphology, crystalline composition, and barriers of typical surface reactions were explored. The exposed facets of Ni show distinct thermodynamic and kinetic sensitivity to carbon deposition and permeation. Thermodynamically, with increasing carbon chemical potential, the carbon coverage and the surface energies of facets change, which leads to the evolving of the equilibrium morphology of Ni particles, favoring higher exposure of the (111) surface. MD simulations show that carbon deposition triggers surface reconstruction at high temperature, and the rate of carbon permeation increases with temperature. Kinetically, the permeation on most Ni surfaces is facile at relatively low temperature except for (111), which shows a threshold temperature of 800 K. Evaluation of a representative probe reaction (methane activation) shows that the reaction barrier and reaction energy increase with the degree of carbide formation, while no general trend is observed for the reverse reaction (CH3 + H). Our study provides an atomic level insight into the carbon deposition process on Ni surfaces and indicates that it is crucial to consider carbon deposition and permeation to understand the particle morphology, crystalline composition, and catalytic performances of Ni.

The in situ formation and removal of coke is a critical problem in heterogeneous catalysis, but its mechanism is not well understood. This work investigates the mechanism of carbon deposition and hydrogenation on an Fe cluster under high-temperature conditions with the density functional tight-binding (DFTB) based nanoreactor molecular dynamics (NMD) method. Our study shows that successive formation of carbon chains, rings, and fused rings occurred during the carbon deposition on Fe clusters. Hydrogenation of activated carbon happens through direct C-H coupling, while the hydrogenation of graphitic carbon involves hydrogenation of the edge carbon, ring-opening reaction, and dealkylation reaction. The main function of the Fe catalyst is to provide the active sites for H-2 dissociation and dissociated H spillover, while its activity toward C-C bond breaking is limited. These results highlight the role of the DFTB-NMD method as an effective tool to investigate reaction mechanisms under operating conditions in heterogeneous catalysis.

Three BiVO4 morphologies, varying in the surface ratios corresponding to high and low index planes, (-121) and (040), respectively, were synthesized and directly grown on a conducting substrate. These three different substrates were evaluated for electrochemical water oxidation reaction to preferentially form hydrogen peroxide at the anode. Experimental results show that the prevalence of high-index plane (-121) contributes favourably for producing H2O2, against O-2 formation. Furthermore, density functional theory studies show that the adsorption behavior of HCO3 species on these high-index surfaces lends to a possible explanation that accounts for better stability of the evolving H2O2 molecules. The HCO3 species adsorbed on the low-index surface are shown to contribute to a pathway that leads to the decomposition of the H2O2 molecule. This observation is purported to contribute to a lower H2O2 generation efficiency for low index facets. These important differences on the two surfaces, brought about by the structure of the surface-adsorbed HCO3 species, highlight the mechanistic coadsorption route which is important for contributing to the overall knowledge that both the catalyst surface structure and binding of the HCO3 species in unison aid in either stabilization or degradation of H2O2.

To understand the effect of the in situ carbon deposition and permeation process on cobalt-catalyzed heterogeneous reactions, the thermodynamics and kinetics of the carburization process of ten different surfaces of hexagonal close-packed (hcp) and face-centered cubic (fcc) Co and the resulting evolution of crystalline morphology, electronic structure, and barriers of typical surface reactions are explored theoretically using density functional theory (DFT) and atomistic thermodynamics methods. The exposed facets of hcp-Co and fcc-Co crystallites showed distinct thermodynamic and kinetic sensitivity to the permeation of carbon into subsurface positions. The formation of surface carbides depends on both the working condition and the type of crystalline facets. Two types of carbon permeation mechanisms were discovered with distinct diffusion paths and barriers. The morphology of cobalt catalysts was found to be greatly modulated by carbon deposition under operando conditions, favoring (0001) of the hcp phase and (111) of the fcc phase at high carbon chemical potentials. As the carbon coverage increases, the d-band centers of the carburized Co surface approach the values of bulk cobalt carbides. Evaluation of a representative Fischer-Tropsch side reaction (CH3 -H coupling in methane formation) shows that the barrier is highly influenced by the degree of carbide formation on the cobalt surfaces. Our study indicates that it is crucial to consider the chemical potential of gas-phase carbon to understand the surface carbon adsorption and permeation phenomenon on the skin layer of the catalyst, the overall cobalt morphology, and the observed catalytic performance of cobalt catalysts in syngas conversion.

The present density functional theory study provides insight into the reactivity of the surface metal atoms of extended/periodic Rh surfaces, clusters, and nanoparticles toward CO adsorption and dissociation. Our results demonstrate that the defect site in a B-5 configuration is the most active one for CO dissociation on all three considered systems. However, the reactivity of the B-5 site for CO dissociation depends critically on the size of the system. The barrier for CO dissociation barrier on the B-5 site increases for smaller particles. The lowest barrier is found for the B-5 site of a stepped Rh (211) surface. CO dissociation on this site occurred with a barrier below the desorption energy of CO.

Strong interest in the Fischer-Tropsch reaction that converts synthesis gas into hydrocarbons is reappearing because it is basic to one of the major routes that convert natural gas into liquid energy carriers. For catalytic science it provides amongst others an opportunity to revisit still open mechanistic issues of the Fischer-Tropsch conversion reaction. New approaches as computational advances and development of model systems are tools that may provide new insights. In this paper we will review our current understanding of the kinetics and its relation to catalyst structural parameters that determine the selectivity of the reaction. In the introductory section we formulate the key questions that we will address. Especially we will discuss the reason for particle size dependence of metallic catalysts as Co and Ru when particles are in the nanosize range and also the apparent paradox that step-edge sites are necessary for the chain growth reaction, where the CO molecule has to dissociate but that such sites should not be poisoned by the presence of the growing hydrocarbon chains or deactivating carbonaceous residue. One of the main selectivity issues of this reaction is the desire to produce long chain hydrocarbon molecules, without co-production of light gas molecules as methane. We will begin the presentation with the elementary kinetic expressions that enable calculation of the selectivity from a microkinetics reaction scheme. This will highlight that the rate of chain growth termination has to be one of the slow reaction steps and also that CO dissociation has to be fast. Since the past decade has seen major advances in the understanding of the structure sensitivity of transition metal catalysed surface reactions, the kinetic analysis helps to understand how structure sensitivity affects Fischer-Tropsch selectivity. Quantum chemical computational studies now can be used to analyse reaction paths and estimate reaction intermediate adsorption energies. Also activation free energies can be deduced for elementary surface reactions. We will illustrate this by discussing a so-called dual site model of the reactive catalyst center. On this reaction center we will discuss in detail CO dissociation and initiation of the chain growth reaction. It appears that synchronized subsequent reaction events involving reaction intermediate diffusion to different positions at the reaction center leads to accommodation of hydrocarbon chain growth while CO dissociation is not suppressed. Ultimately the mechanistic model deduced from the quantum-chemical studies will have to be used in kinetic equations to predict overall catalytic conversion rates. We will demonstrate how this can be done in a Kinetic Monte Carlo scheme, in which no assumption on the rate limiting step has to be made. We will present the results of some initial simulations where we allow for growth of short hydrocarbon chains. These results can be used in an insightful way using the kinetic model equations presented earlier in the paper. The paper is concluded by discussing the implications of these model results for our general mechanistic understanding of the Fischer-Tropsch reaction.

A critical issue in the Fischer-Tropsch synthesis reaction is the blocking of the active sites for low barrier CO dissociation by the C(1) adsorbed species generated from CO dissociation, which can hinder the further steps in the FT process. Here, we propose a synchronized pathway for low barrier CO dissociation and C-C coupling on a corrugated Ru surface.

Synthesis of fuel from syngas via the Fischer–Tropsch (F–T) process is considered to be one of the important reactions in the field of heterogeneous catalysis. Here, we present a short review on the mechanism of the CO dissociation which is regarded as the initial step in the F–T process. The analysis is based on the earlier and recent propositions on the carbide and hydrogen assisted mechanisms for the CO dissociation on Ru and Co surfaces.

A review on the analysis based on our recent theoretical results on the site specific activation of CO, N2 and NO on corrugated Ru surface is presented. We discuss the issues such as what should be the configuration of the active site for the optimum dissociation of the diatomic molecules?, How is the barrier dependent on the structure of the reaction path?, Whether the further steps involved in the reaction sequence dependent on the activation of the diatomic molecules?