Multiscale modeling of complex chemical systems requires algorithms that operate coherently across electronic, atomistic, mesoscopic, and continuum scales. While quantum algorithms have been proposed for each regime, no systematic framework exists to compose them across scale boundaries. Here, we identify the conditions under which fault-tolerant quantum algorithms might preserve scale-specific quantum advantages. We map quantum phase estimation, Hamiltonian simulation with Gibbs state preparation, quantum random walks, and quantum partial differential equation solvers onto electronic structure, molecular dynamics, mesoscopic kinetics, and continuum reactor physics, respectively. Crucially, these correspondences do not imply unconditional end-to-end quantum advantage; speedups depend heavily on state preparation, memory architectures, matrix conditioning, and classical readout costs. Six unresolved questions define this composition problem, illustrated via a quantum hierarchy for CO oxidation over Pt(111). We propose viewing inter-scale transfer as a quantum channel composition problem at the interface of algorithm design and non-equilibrium statistical mechanics, and ask whether information loss at scale boundaries is intrinsic to multiscale modeling or merely a consequence of lossy classical transduction between algorithmic layers. The resulting roadmap suggests that multiscale quantum advantage is governed primarily by the structure of information transfer between algorithmic layers, rather than by performance at individual scales alone.

We lay the foundation for a quantum algorithmic framework to analyse fixed-structure chemical reaction networks (CRNs) using quantum random walks (QRWs) via electrical circuit theory. We model perturbations to CRNs, such as, species injections that shift steady-state concentrations, while keeping the underlying species-reaction graph fixed. Under physically meaningful mass-action constraints, we develop quantum algorithms that (i) decide reachability of target species after perturbation, (ii) sample representative reachable species, (iii) approximate steady-state fluxes through reactions, and (iv) estimate total Gibbs free-energy consumption. Our approach offers new tools for analysing the structure and energetics of complex CRNs, and opens up the prospect of scalable quantum algorithms for chemical and biochemical reaction networks.

A central challenge in water electrolysis lies with the oxygen evolution reaction (OER) where the formation of molecular oxygen (O 2 ) is hindered by the constraint of angular momentum conservation. While the reactants OH − or H 2 O are diamagnetic (DM), the O 2 product has a paramagnetic (PM) triplet ground state, requiring a change in spin configuration when being formed. This constraint has prompted interest in spin‐selective catalysts as a means to facilitate OER. In this context, the roles of magnetism and chirality‐induced spin selectivity (CISS) in promoting the OER reaction have recently been investigated through both theoretical and experimental studies. However, pinpointing the key principles and their relative contribution in mediating spin‐enhancement remains a significant challenge. This roadmap offers a forward‐looking perspective on current experimental trends and theoretical developments in spin‐enhanced OER electrocatalysis and outlines strategic directions for integrating incisive experiments and operando approaches with computational modeling to disentangle key mechanisms. By providing a conceptual framework and identifying critical knowledge gaps, this perspective aims to guide researchers toward dedicated experimental and computational studies that will deepen the understanding of spin‐induced OER enhancement and accelerate the development of next‐generation catalysts.

One limitation of current quantum hardware is the restricted connectivity between qubits, as described by the hardware’s coupling graph. To overcome this limitation, efficient qubit routing strategies are necessary. We introduce line-graph qubit routing, which routes circuits defined on line graphs to hardware with a heavy coupling graph. We implement line-graph qubit routing and demonstrate its effectiveness in mapping quantum circuits defined kagome, checkerboard, and shuriken lattices to hardware with heavy-hex, heavy-square, and heavy-square-octagon coupling graphs, respectively. Benchmarking shows the ability of line-graph qubit routing to outperform established general-purpose methods in a fraction of the computational time, while offering a depth reduction by up to a factor of 5. Line-graph qubit routing has direct applications in the quantum simulation of lattice-based models, serves as a suitable benchmark for other routing methods, and aids the exploration of the capabilities of near-term quantum hardware.

Heterogeneous catalysis plays a critical role in many industrial processes, including the production of fuels, chemicals, and pharmaceuticals, and research to improve current catalytic processes is important to make chemical industry more sustainable. Despite its importance, the challenge of identifying optimal catalysts with the required activity and selectivity persists, demanding a detailed understanding of the complex interactions between catalysts and reactants at various length and time scales. Density functional theory (DFT) has been the workhorse in modelling heterogeneous catalysis for more than three decades. While DFT has been instrumental, this review explores the application of quantum computing algorithms in modelling heterogeneous catalysis, which could bring a paradigm shift in our approach to understanding catalytic interfaces. Bridging academic and industrial perspectives, focusing on emerging materials such as multi-component alloys, single-atom catalysts, and magnetic catalysts, we delve into the limitations of DFT in capturing strong correlation effects and spin-related phenomena. The review also presents important algorithms and their applications relevant to heterogeneous catalysis modelling, showcasing advancements in the field. Additionally, the review explores embedding strategies where quantum computing algorithms handle strongly correlated regions, while traditional quantum chemistry algorithms address the remainder, offering a promising approach for large-scale heterogeneous catalysis modelling. Looking forward, ongoing investments by academia and industry reflect a growing enthusiasm for quantum computing's potential in heterogeneous catalysis research. The review concludes by envisioning a future where quantum computing algorithms seamlessly integrate into research workflows, propelling us into a new era of computational chemistry and thereby reshaping the landscape of modelling heterogeneous catalysis.

Confined catalysis between a two-dimensional (2D) cover and metal surfaces has provided a unique environment with enhanced activity compared to uncovered metal surfaces. Within this 2D confinement, weakened adsorption and lowered activation energies were observed using surface science experiments and density functional theory (DFT) calculations. Computationally, the role of electronic and mechanical factors responsible for the improved activity was deduced only from static DFT calculations. This demands a detailed investigation on the dynamics of reactions under 2D confinement, including temperature effects. In this work, we study CO oxidation on a 2D graphene covered Pt(111) surface at 90 and 593 K using DFT-based ab initio molecular dynamics simulations starting from the transition state configuration. We show that CO oxidation in the presence of a graphene cover is substantially enhanced (2.3 times) at 90 K. Our findings suggest that 2D confined spaces can be used to enhance the activity of chemical reactions, especially at low temperatures.

Several full-dimensional potential energysurfaces (PESs) are reported for vibrating CO adsorbates at two coverages on arigid NaCl(100) surface based on first principles calculations. These PESsreveal a rather flat energy landscape for physisorption of vibrationless CO onNaCl(100), evidenced by various C-down adsorption patterns within a smallenergy range. Agreement with availableexperimental results is satisfactory, although quantitative differences exist.These PESs are used to explore isomerization pathways between the C-down andhigher energy O-down configurations, which reveal a significant isomerizationbarrier. As CO vibration is excited, however, the energy order of the twoisomer changes, which helps to explain the experimental observed flipping ofvibrationally excited CO adsorbates.

Direct chemical dynamics simulations at high temperatures of reaction between O-3(2) and graphene containing varied number of defects were performed using the VENUS-MOPAC code. Graphene was modeled using (5a,6z)-periacene, a poly aromatic hydrocarbon with 5 and 6 benzene rings in the armchair and zigzag directions, respectively. Up to six defects were introduced by removing carbon atoms from the basal plane. Usage of the PM7/unrestricted Hartree-Fock (UHF) method, for the simulations, was validated by benchmarking singlet-triplet gaps of n-acenes and (5a,nz) periacenes with high-level theoretical calculations. PM7/UHF calculations showed that graphene with different number of vacancies has different ground electronic states. Dynamics simulations were performed for two O-3(2) collision energies E-i of 0.4 and 0.7 eV, with the incident angle normal to the graphene plane at 1375 K. Collisions on graphene with one, two, three, and four vacancies (1C-, 2C-, 3C-, and 4C-vacant graphene) showed no reactive trajectories, mainly due to the nonavailability of reactive sites resulting from nascent site deactivation, a dynamical phenomenon. On the other hand, O-3(2) dissociative chemisorption was observed for collisions on four- (with a different morphology), five- and six-vacant graphene (4C-2-, 5C- and 6C-vacant graphene). A strong morphology dependence was observed for the reaction conditions. On all reactive surfaces, larger reaction probabilities were observed for collisions at E-i = 0.7 eV. This is in agreement with the nucleation time measured by supersonic molecular beam experiments wherein about 2.5 times longer nucleation time for O-2 impinging at 0.4 eV compared with 0.7 eV was observed. Reactivity at both collision energies, viz., 0.4 and 0.7 eV, showed the following trend: 5C- < 6C- < 4C-vacant graphene. Formation of carboxyl/semiquinone (C=O)- and ether (-C-O-C-)-type dissociation products was observed on all reactive surfaces, whereas a higher probability of formation of the ether (-C-O-C-) group was found on 4C-vacant graphene on which dangling carbon atoms are present in close proximity. However, no gaseous CO/CO2 formation was observed on any of the graphene vacancies even for simulations that were run up to 10 ps. This is apparently the result of the absence of excess oxygen atoms that can aid the formation of larger groups, the precursors for CO/CO2 formation. Although the results of this study do not provide a conclusive understanding of the mechanism of graphene/graphite oxidation, this work serves as an initial study attempting to understand the O-3(2) dissociative chemisorption dynamical mechanism on defective-graphene/graphite surfaces at high temperatures.

Methane-dissociative chemisorption is the rate-determining step in the industrially important steam reforming and dry reforming reactions of methane. Widely used industrial catalysts containing Ni as the active metal face the problems of carbon deposition and deactivation, whereas Pt surfaces with lower barrier are expensive to be used in the industrial scale. Using density functional theory calculations, a series of surface and subsurface Ni-Pt bimetallic surfaces were studied to understand the synergistic catalytic activity of alloying elements toward facilitating methane dissociation and in resisting carbon formation. Addition of Ni to Pt(111) decreased activation energy barriers, whereas a linear increase m barner was found when Pt is added to Ni(111) surface. The observed reactivity trends were explained using surface-based descriptors like work function, surface energy, and d-band center and also using energy-based descriptors, namely, Bronsted-Evans-Polanyi and transition-state scaling relationships. Changes m barner heights and locations of the barner with lattice atom motion were calculated to include the effect of surface temperature on dissociation probabilities. Dissociation probabilities thus calculated at different surface temperatures using semiclassical methods showed that reactivity increased with surface temperature on all surface alloys. Overall, two surfaces, viz., Ni9/Pt(111) and subPt9/Ni(111), showed improved behavior toward CH4 dissociation, irrespective of the composition of underlying layers. C-2 formation on these two alloys also showed higher barners compared to pure Ni(111) surface. However, considenng all aspects like energy barriers to CH4 dissociation and CH dissociation, carbon adsorption energy, and cost, the subsurface alloy, sub-Pt9/ Ni(111), showed an enhanced overall performance as a reforming catalyst.

A comparative study of mode-selectivity of water dissociation on Ni(100), Ni(110), and Ni(111) surfaces is performed at the same level of theory using a fully quantum approach based on the reaction path Hamiltonian. Calculations show that the barrier to water dissociation on the Ni(110) surface is significantly lower compared to its close-packed counterparts. Transition states for this reaction on all three surfaces involve the elongation of one of the O-H bonds. A significant decrease in the symmetric stretching and bending mode frequencies near the transition state is observed in all three cases and in the vibrational adiabatic approximation, excitation of these softened modes results in a significant enhancement in reactivity. Inclusion of non-adiabatic couplings between modes results in the asymmetric stretching mode showing a similar enhancement of reactivity as the symmetric stretching mode. Dissociation probabilities calculated at a surface temperature of 300 K showed higher reactivity at lower collision energies compared to that of the static surface case, underlining the importance of lattice motion in enhancing reactivity. Mode selective behavior is similar on all the surfaces. Molecules with one-quantum of vibrational excitation in the symmetric stretch, at lower energies (up to ∼0.45 eV), are more reactive on Ni(110) than the Ni(100) and Ni(111) surfaces. However, the dissociation probabilities approach saturation on all the surfaces at higher incident energy values. Overall, Ni(110) is found to be highly reactive toward water dissociation among the low-index nickel surfaces owing to a low reaction barrier resulting from the openness and corrugation of the surface. These results show that the mode-selective behavior does not vary with different crystal facets of Ni qualitatively, but there is a significant quantitative effect.

Water dissociation is the rate-determining step (RDS) in the industrially important water gas shift (WGS) reaction. Low temperature Cu catalysts are limited by a higher barrier to dissociation whereas Ni surfaces with lower barriers for this reaction are deactivated by carbon deposition due to CO dissociation. Density functional theory (DFT) calculations are performed on a series of overlayer and subsurface bimetallics starting with Ni(111) and Cu(111) to understand the synergistic catalytic activity of Cu/Ni bimetallics toward H2O dissociation which is the RDS. Surface parameters like surface energy, work function and density of states were calculated and were correlated with the change in reactivity. Transition state (TS) calculations showed that addition of Ni to Cu(111) surfaces decreased dissociation barriers while the scenario is reversed when Cu atoms replace Ni in Ni(111) surface with no linear relation with any calculated surface properties in both cases. Linear relations were found to correlate well the reaction energies with the activation energy barriers. Effects of surface temperature were induded by determining the change in the barrier heights and barrier locations with lattice atom motion calculated from TS calculations. Dissociation probabilities calculated at different surface temperatures Using semiclassical methods showed that increase in surface temperature increases dissociation probabilities where the extent of increase is strongly dependent on the change in barrier heights. Overall, Ni addition to Cu(111) surface proved beneficial while the Cu addition to Ni(111) surface proved detrimental to H2O dissociation.

The present work studied water adsorption and dissociation on low-index nickel surfaces using DFT and semi-classical methods. Using a relatively simple model, a qualitative picture of the lattice effect on water dissociation was presented in this study. To improve upon the results and understand the mode-selectivity in this reaction, reaction path Hamiltonian (RPH) approach is employed. This model is limited to only predict the efficacies of stretching frequencies and hence could not give correct values for the efficacy of the bending modes. It suggests that the inclusion of non-adiabatic coupling is important of understand mode-selectivity completely. Our studies demonstrated that inclusion of surface temperature effect is important when gas-surface reactions are modeled. Usage of RPH and ‘sudden’ model for surface temperature will be helpful in understanding the reactivity qualitatively on large number of surfaces. From these studies, it is clear that understanding and prediction of mode-selectivity and bond-specificity is important when studying molecules on metal surfaces. This can be very useful in controlling the product specification and yield. With increasing computing facilities and faster algorithms, these types of studies can possibly be extended to larger molecules in the future. If happens, it will be a beginning of new era in the field of reaction dynamics.

Effects of addition of P to Co–W coatings from gluconate bath using direct current (DC) and pulse current (PC) methods have been investigated in this study. Co–W–P coatings with different P concentrations are prepared by varying hypophosphite concentration in the bath. Current efficiency of the Co–W–P electrodeposition is lower than that for Co–W coatings. Increase in NaH2PO2 concentration increases the cobalt content significantly and decreases the tungsten content drastically. Co–W–P coatings display ‘cauliflower‐like’ morphology and roughness of the coatings increases with increasing P content. As‐deposited Co–W–P deposits are amorphous while heat treatment at different temperatures has rendered them crystalline with the precipitation of stable species like, Co3W, Co2P, etc. Unlike Co–W coatings, Co–W–P shows two‐step crystallization in differential scanning calorimetry (DSC) and on heat treatment, which is similar to the behavior of Co–P electrodeposited from gluconate baths. Moreover, inclusion of phosphorous and heat treatment have led to significant increase in microhardness of the Co–W–P coatings. X‐ray photoelectron spectroscopy (XPS) studies provide a detailed insight into the nature of Co, W and P species in as‐deposited and sputtered coatings. Microhardness of the heat‐treated coatings is higher than the as‐deposited counterparts and is comparable with that of hard chromium. Copyright © 2016 John Wiley & Sons, Ltd.

Size dependency of methane adsorption and dissociation on nickel nanoclusters containing 6, 13 and 19 atoms are studied using density functional theory (DFT) calculations. Methane physisorption was identified only on top sites on all the nanoclusters. Elongation of the dissociating C-H bond was found on Ni-6 and Ni-13 nanoclusters while on Ni-19 no such elongation was found. Transition state calculations revealed that barrier for methane dissociation on Ni-6 and Ni-13 clusters are nearly half the barrier for dissociation on Ni-19 cluster. Comparison of activation energies with this and the previous studies, suggest no geometry dependence i.e., only electronic effect prevails for nanoclusters containing less than similar to 13 nickel atoms. For smaller nanoclusters (Ni-6 and Ni-13) the elongation of the dissociating C-H bond in the adsorbed state acts as the precursor state for dissociation, thereby reducing the energy barrier for methane dissociation. However, no sign of precursor formation is observed in the case of Ni-19 nanocluster and hence a large barrier. Semi-classical dissociation probability plots show high dissociation probabilities for Ni-6 and Ni-13 nanoclusters compared to Ni-19 clusters and low-indexed nickel surfaces. (C) 2015 Elsevier B.V. All rights reserved.

Co–P coatings with low and high phosphorous contents are electrodeposited using direct current (DC) and pulse current (PC) methods from cobalt chloride baths.

Water adsorption and dissociation on Ni(110) surface is studied in detail and compared with its close packed counterparts using density functional theory calculations. Water adsorption occurs on the top site as found on Ni(100) and Ni(111) but the adsorption is stronger on Ni(110). H and OH preferably adsorb on the short bridge sites (brgshort) opposed to hollow sites on (100) and (111) surfaces. Energy barriers for water molecule dissociation on Ni(110) as obtained from the transition state (TS) calculations were low compared to other Ni low indexed surfaces. TS geometries at different positions of the lattice coordinate, Q, were obtained to study the effect of surface temperature on dissociation of H2O molecules. These calculations revealed that second layer atoms were also involved in the TS. Dissociation probabilities are obtained using a semi-classical approximation by sampling Q for a Boltzmann distribution at different temperatures. Results showed that the increasing surface temperature significantly increases the dissociation probabilities at lower energies and saturates near the barrier for dissociation. Although the contribution from both top and second layers is similar at low surface temperatures, motion of top layer atoms contribute more towards dissociation probability at higher surface temperatures. Dissociation probabilities obtained are more than one order of magnitude higher than that on Ni(100) and Ni(111) surfaces suggesting Ni(110) to be more reactive among the low indexed Ni surfaces.

A detailed quantum chemical study has been carried out at the CCSD(T) level of theory to understand the behavior of water dimer under the influence of external electric fields. The energy values obtained at this level of theory follow the same trend as observed with the DFT and MP2 levels of theory. Our calculations show that water dimer gets stabilized with increase in the strength of electric field. A slight increase in the hydrogen bond distance and relatively larger decrease in the hydrogen bond angle is found with the increase in the strength of electric field. The dipole moment and HOMO-LUMO energy gap increase with the increase in the strength of electric field.

Co–W alloy coatings were deposited with direct current (DC) and pulse current (PC) electrodeposition methods using gluconate bath at pH5 and characterized by X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). DSC studies hint at the possibility of formation of metallic glasses. Detailed XPS studies of these alloy coatings have been carried out to compare elemental states and composition of Co and W in DC and PC electrodeposited alloys. DC-plated alloy has significant amount of Co and W metal along with their respective oxidized species. In contrast, mainly oxidized metals are present in the following layers of as-deposited coatings prepared with PC plating. Concentration of Co metal is observed to increase during sputtering, whereas there is no change in W6+ concentration. Microhardness measurement of all the Co–W coatings shows higher hardness compared to Co metal and 1:1 and 1:4 PC electrodeposited coatings show little higher hardness compared to 1:2 PC electrodeposited coating.