Complete Reaction Pathway Research Articles

Integrating Active Learning and DFT for Fast-Tracking Single-Atom Alloy Catalysts in CO2-to-Fuel Conversion.

Electrocatalytic carbon dioxide reduction (CO2RR) technology enables the conversion of excessive CO2 into high-value fuels and chemicals, thereby mitigating atmospheric CO2 concentrations and addressing energy scarcity. Single-atom alloys (SAAs) possess the potential to enhance the CO2RR performance by full utilization of atoms and breaking linear scaling relationships. However, quickly screening high-performance metal portfolios of SAAs remains a formidable challenge. In this study, we proposed an active learning (AL) framework to screen high-performance catalysts for CO2RR to yield fuels such as CH4 and CH3OH. After four rounds of AL iterations, the ML model attained optimal prediction performance with the test set R2 of approximately 0.94 and successful prediction was achieved for the binding free energy of *CHO, *COH, *CO, and *H on 380 catalyst surfaces with an accuracy within 0.20 eV. Subsequent analysis of the SAA catalysts' activity, selectivity, and stability led to the discovery of eight previously unexplored SAA catalysts for CO2RR. Notably, the surface activity of Ti@Cu(100), Au@Pt(100), and Ag@Pt(100) shines prominently. Utilizing DFT calculations, we elucidated the complete reaction pathway of the CO2RR on the surfaces of these catalysts, confirming their high catalytic activity with limiting potentials of -0.11, -0.34, and -0.46 eV, respectively, which are significantly lower than those of pure Cu catalysts. The results showcase the exceptional predictive prowess of AL, providing a valuable reference for the design of CO2RR catalysts.

Nonprecious Single Atom Catalyst for Methane Pyrolysis.

The development of a suitable catalytic system for methane pyrolysis reactions requires a detailed investigation of the activation energy of C-H bonds on catalysts, as well as their stability against sintering and coke formation. In this work, both single-metal Ni atoms and small clusters of Ni atoms deposited on titanium nitride (TiN) plasmonic nanoparticles were characterized for the C-H bond activation of a methane pyrolysis reaction using ab initio spin-polarized density functional theory (DFT) calculations. The present work shows the complete reaction pathway, including energy barriers for C-H bond activation and dehydrogenated fragments, during the methane pyrolysis reaction on catalytic systems. Interestingly, the C-H bond activation barriers were low for both Ni single-atom and Ni-clusters, showing the energy barriers of ~1.10 eV and ~0.88 eV, respectively. Additionally, single-atom Ni-TiN showed weaker binding to adsorbates, and a net endothermic reaction pathway indicated that the single-atom Ni-TiN was expected to resist coke formation on its surface. However, these Ni single-atom catalysts can sinter, aggregate into a small cluster, and form a coke layer from the highly exothermic reaction pathway that the cluster takes despite the facile reaction pathway.

Biocatalytic Carbenoid N-H Insertions Via Engineered Myoglobins: A Systematic Reaction Mechanism Study

Recently engineered myoglobins have demonstrated excellent biocatalytic activities for a broad range of carbenoid N-H insertion reactions with up to >99% yield. Such biocatalysts offer various tuning points beyond protein residues, such as metal center, and axial ligand, to regulate different chemical reactivities. However, there is no computational mechanistic study to reveal its basic reaction mechanism, which could be utilized to study effects of different catalyst component for rational biocatalyst design. The reported computational mechanistic papers of other heme protein catalyzed N-H insertion have limited information without a careful comparison of all possible pathways and just focused on certain steps. Building on our group’s recent mechanistic work on a number of heme carbene transfer reactions, we performed a quantum chemical study to systematically study all possible reaction pathways for myoglobin catalyzed N-H insertions, which starts from the reactants to final released products and thus constitute a complete reaction pathway study. We examined ylide (proton transfer), hydrogen atom transfer, and hydride transfer pathways. In the favored ylide pathways, we calculated the direct proton transfer from amine to carbene and indirect paths with both concerted and stepwise proton transfer and dissociation components. For the indirect pathways in which the proton resides on the carbonyl oxygen of the original carbene substituent, subsequent water-assisted proton transfer from this carbonyl oxygen to carbene’s carbon to form the final product was also investigated. The most favorable pathway from this systematic reaction mechanism study was further supported by new experimental work from our collaborators, the original developer of myoglobin-based biocatalysts. These novel mechanistic results provide important mechanistic information for future biocatalyst design with enhanced reactivities.

Screening for electrocatalytic reduction of N2 by borophene supported bimetallic atoms

Ammonia (NH3), as a high energy density chemical and hydrogen energy storage medium, has garnered significant interest in the realms of energy storage and catalysis. In contrast to the traditional Haber-Bosch process, the electrocatalysis nitrogen reduction reaction (eNRR) can synthesize green ammonia under mild reaction conditions. Based on density functional theory (DFT), the potential of 2D borophene supported transition metals as bimetallic atomic catalysts (BACs) in eNRR was investigated. Progressive screening through energy-oriented screening mechanism, Sc2B12, Ti2B12, V2B12 and Zr2B12 were identified as potential eNRR catalysts. Their complete reaction pathways and Gibbs free energy (ΔG) were further explored, and corresponding overpotentials were obtained. The results showed that overpotentials of the potential determining steps (PDS) of these catalysts were 0.34, 0.40, 0.39 and 0.13 V, respectively, demonstrating excellent eNRR catalytic activity and good selectivity. Cu2B12 shows remarkable hydrogen evolution reaction (HER) catalytic activity with an overpotential (η) of only 0.05 V. The study also revealed that the catalytic activity of TM2B12 is derived from its excellent conductivity, and the charge transmission enhances the catalyst activity of eNRR. Consequently, this study provides significant theoretical guidance and support for the synthesis of novel eNRR catalysts, and promotes further advancement in the field of catalysis.

The study of strong metal-support interaction enhanced PdZn alloy nanocatalysts for methanol steam reforming

Methanol steam reforming faces a significant challenge due to CO formation, which can lead to poisoning of fuel cell electrodes. This study introduces a series of Pd/ZnO catalysts prepared by ethylene glycol reduction, exhibiting remarkable selectivity in methanol steam reforming (MSR). The majority of palladium species exist in the form of PdZn alloy, attributed to the dual reduction process. This process, along with the generation of zinc vacancies and oxygen vacancies, enhances the interaction between the metal-carrier, promoting the formation of PdZn alloy, significantly improving CO2 selectivity and catalytic activity. Even at a high temperature of 400 °C, the active phase remains stable. After 5 hours of MSR, the 3% Pd/ZnO-300 H2 catalyst achieves a hydrogen production rate of 1628.0 mmol·gcat−1·h−1, with methanol conversion stabilized at 94%, CO2 selectivity reaching 97.7%, and CO content as low as 0.5%. These results outperform recent studies on hydrogen production. Furthermore, DFT calculations elucidate the complete reaction pathway (111) on PdZn. This study provides initial insights into the influence of metal-carrier interaction on the formation of PdZn alloy, suggesting a new direction for palladium-based catalysts in methanol steam reforming.

Molecular Insights into Bifunctional Ambruticin DH3 for Substrate Specificity and Catalytic Mechanism.

Dehydratase (DH), a domain located at polyketide synthase (PKS) modules, commonly catalyzes the dehydration of β-hydroxy to an α,β-unsaturated acyl intermediate. As a unique bifunctional dehydratase, AmbDH3 (the DH domain of module 3 of the ambruticin PKS) is verified to be responsible for both dehydration and the following pyran-forming cyclization. Besides, in vitro studies showed that its catalytic efficiency varies with different chiral substrates. However, the detailed molecular mechanism of AmbDH3 remains unclear. In this work, the structural rationale for the substrate specificity (2R/2S- and 6R/6S-substrates) in AmbDH3 was elucidated and the complete reaction pathways including dehydration and cyclization were presented. Both MD simulations and binding free energy calculations indicated AmbDH3 had a stronger preference for 2R-substrates (2R6R-2, 2R6S-3) than 2S-substrates (2S6R-1), and residue H51 and G61 around the catalytic pocket were emphasized by forming stable hydrogen bonds with 2R-substrates. In addition, AmbDH3's mild tolerance at C6 was explained by comparison of substrate conformation and hydrogen bond network in 6S- and 6R-substrate systems. The QM/MM results supported a consecutive one-base dehydration and cyclization mechanism for 2R6S-3 substrate with the energy barrier of 25.2 kcal mol-1 and 24.5 kcal mol-1 , respectively. Our computational results uncover the substrate recognition and catalytic process of the first bifunctional dehydratase-cyclase AmbDH3, which will shed light on the application of multifunctional DH domains in PKSs for diverse natural product analogs and benefit the chemoenzymatic synthesis of stereoselective pyran-containing products.

Correlation between the Properties of Surface Lattice Oxygen on NiO and Its Reactivity and Selectivity towards the Oxidative Dehydrogenation of Propane.

Modified NiO catalysts with controllable vacancies and dopants are promising for alkene production from oxidative dehydrogenation (ODH) of light alkanes, and a molecular understanding of the modification on elementary reaction steps would facilitate the design of highly efficient catalysts and catalytic processes. In this study, density functional theory (DFT) calculations was used to map out the complete reaction pathways of propane ODH on the NiO (100) surfaces with different modifiers. The results demonstrated that the presence of vacancies (O and Ni) and dopants (Li and Al) alters the electrophilicity of surface oxygen species, which in turn affects the reactivity towards C-H bond activation and the overall catalytic activity and selectivity. The strongly electrophilic O favors a radical mechanism for the first C-H activation on O followed by the second C-H activation on O-O site, whereas weak electrophilic O favors concerted C-H bond breaking over Ni-O site. The C-H bond activation proceeds through a late transition state, characterized by the almost completion of the O-H bond formation. Consequently, the adsorption energy of H adatom on O rather than p-band center or Bader charge of O has been identified to be an accurate descriptor to predict the activation barrier for C-H breaking (activity) as well as the difference between the activation barriers of propene and CH3 CCH3 (selectivity) of ODH.

Complete catalytic reaction of mercury oxidation on CeO2/TiO2 (001) surface: A DFT study

CeO2/TiO2 catalyst is a promising material for realizing the integration of denitrification and mercury removal to reduce mercury emissions. Oxidation mechanism of Hg0 on CeO2/TiO2 (001) surface in the presence of HCl and O2 was studied by density functional theory (DFT). The results indicated that Hg0 was physically adsorbed on CeO2/TiO2 (001) surface. As an important intermediate, HgCl was adsorbed on the surface of CeO2/TiO2 (001) utilizing enhanced chemisorption, while the adsorption energy of HgCl2 was only −57.05 kJ/mol. In the absence of HCl, mercury oxidation followed the Mars-Maessen mechanism with a relatively high energy barrier, and the product (HgO) was difficult to desorb, which hindered the reaction process. When HCl existed, reactive chlorine (Cl*) would be produced by the dissociation of HCl, and the mercury oxidation would follow the Langmuir-Hinshelwood mechanism. The co-existence of HCl and O2 had no significant effect on the adsorption of Hg0, but reduced the reaction energy barrier and the final product (HgCl2) was more easily desorbed from the catalyst surface. In addition, two complete cyclic reaction pathways for catalytic oxidation of Hg0 on CeO2/TiO2 (001) surface were constructed to clarify the detailed reaction process.

Simultaneous CO2 capture and functionalization: solvated electron precursors as novel catalysts.

Metal complexes with diffuse solvated electrons (solvated electron precursors) are proposed as alternative catalysts for the simultaneous CO2 capture and utilization. Quantum chemical calculations were used to study the reaction of CO2 with H2 and C2H4 to produce formic acid, methyldiol and δ-lactone. Mechanisms of a complete reaction pathway are found and activation barriers are reasonably low. The metal ligand complex readily reduces CO2 and significantly stabilizes CO2˙-. Ligand identity minimally influences the reaction. Additional reactions and future strategies are proposed with the goal of inducing experimental interest.

Electrochemical oxygen reduction reaction at conductive polymer PEDOT: Insight from ab initio molecular dynamics simulations

Conducting polymers such as poly (3,4-ethylenedioxythiophene) (PEDOT) have attracted research attention as promising effective electrocatalytic materials for Oxygen Reduction Reaction (ORR). However, the complete reaction pathways leading to the hydrogen peroxide, H2O2, formation still remained unexplored. In this study, ab initio Born–Oppenheimer molecular dynamics (MD) calculations with an explicit solvent, were carried out to investigate the detailed mechanisms of the ORR on PEDOT via monitoring MD trajectories and analysing electronic energies. We confirm the outer-sphere nature of the first electron transfer and describe the essentially concerted electron–proton transfer nature of both oxygen reduction steps. Proton transfer is found to be involved in the first and second reduction steps and the role of water as an explicit solvent is outlined. Formation of the hydrogen peroxide is observed via either the reduction of hydroperoxyl radical HO2 or cleavage of its peroxo-adduct with PEDOT. It is therefore theoretically validated that the O2 reduction on a PEDOT may proceed a series pathway occurring simultaneously in acidic media. This approach provides an efficient and reliable means to rationalize and predict reaction mechanisms in solvent environment.

Effect of Surface Oxidation on Oxidative Propane Dehydrogenation over Chromia: An Ab Initio Multiscale Kinetic Study.

An increasingly utilized way for the production of propene is propane dehydrogenation. The reaction presents an alternative to conventional processes based on petroleum resources. In this work, we investigate theoretically how Cr2O3 catalyzes this reaction in oxidative and reducing environments. Although previous studies showed that the reduced catalyst is selective for the non-oxidative dehydrogenation of propane, real operating conditions are oxidative. Herein, we use multiscale modeling to investigate the difference between the oxidized and reduced catalyst and their performance. The complete reaction pathway for propane dehydrogenation, including C–C cracking, formation of side products (propyne, ethane, ethylene, acetylene, and methane), and catalyst coking on oxidized and reduced surfaces of α-Cr2O3(0001), is calculated using density functional theory with the Hubbard correction. Parameters describing adsorption, desorption, and surface reactions are used in a kinetic Monte Carlo simulation, which employed industrially relevant conditions (700–900 K, pressures up to 2 bar, and varying oxidants: N2O, O2, and none). We observe that over the reduced surface, propene and hydrogen form with high selectivity. When oxidants are used, the surface is oxidized, which changes the reaction mechanism and kinetics. During a much faster reaction, H2O forms as a coproduct in a Mars–van Krevelen cycle. Additionally, CO2 is also formed, which represents waste and adversely affects the selectivity. It is shown that the oxidized surface is much more active but prone to the formation of CO2, while the reduced surface is less active but highly selective toward propene. Moreover, the effect of the oxidant used is investigated, showing that N2O is preferred to O2 due to higher selectivity and less catalyst coking. We show that there exists an optimum degree of surface oxidation, where the yield of propene is maximized. The coke, which forms during the reaction, can be burnt away as CO2 with oxygen.

QM/MM Study of Human Transketolase: Thiamine Diphosphate Activation Mechanism and Complete Catalytic Cycle.

A computational model for human transketolase was proposed, showing that thiamine diphosphate activation was based on His110 in place of His481 reported in yeast transketolase. In addition, a complete catalytic reaction pathway was investigated using d-xylulose-5-phosphate and d-ribose-5-phosphate as substrates, showing at every step a perfect superimposition of our model with high-resolution crystallographic structures 3MOS, 4KXV, and 4KXX. This study shows that H2N4' of the active thiamine diphosphate "V form" no longer has a self-activating role but allows self-stabilization of the cofactor and of the Breslow intermediate. These advances in our knowledge of the human transketolase mechanism offer interesting prospects for the design of new drugs, this enzyme being involved in several diseases, and for a better understanding of the reactions catalyzed by transketolases from other sources.

Revealing nature of active site and reaction mechanism of supported chromium oxide catalyst in propane direct dehydrogenation

• The decisive role played by the oxidation state of Cr. • The comparison of reactivity between various oxygen species on CrO X catalysts. • The complete reaction pathway including regeneration. • The role of OH group on SiO 2 support. Chromium oxide is the conventional catalyst for propane direct dehydrogenation. However, the active site and reaction mechanism are still remaining unresolved due to the complicated valence of chromium and co-exists of several active sites. In this work, DFT calculations are performed to reveal the nature of active center and reaction mechanism for the supported chromium catalyst on silica. Three valences of chromium including Cr 3+ , Cr 5+ , and Cr 6+ are examined to give a unbiased survey of reactivity. The reaction pathway and C–H activation are carefully examined. Moreover, a detailed analysis of active site regeneration is performed. The reactivities of different oxygen groups attached to Cr including terminal, bridge, and OH group are evaluated at the same footing. Furthermore, the calculations also reveal the intrinsic catalytic properties of chromium which show comparable abilities with oxygen groups. The influence from OH group on support is also evaluated. The comparisons of different reaction pathway give useful indication on the possible reaction mechanism. In the end, the most favorable active site is identified. The current work not only deepen the understanding of catalytic properties of supported chromium catalyst but also supply the doable optimization methods for further improvements.

Reaction pathways and the role of the carbonates during CO2 hydrogenation over hexagonal In2O3 catalysts

Complete reaction pathways for CO2 hydrogenation to CH3OH and CO on the h-In2O3(012) and h-In2O3(104) flat and step surfaces are investigated by density functional theory (DFT) calculations. By analyzing the complete reaction pathways, bi-HCOO* hydrogenation to H2COO* is found to be the rate-determining step (RDS) for CH3OH formation on the h-In2O3(012) flat surface and h-In2O3(104) flat and step surfaces, OH* protonation to H2O* is determined as the RDS for CH3OH formation on the h-In2O3(012) step surface and that for CO formation on the h-In2O3(012) flat and step surfaces, and bent CO2 configuration (bt-CO2*) protonation to COOH* is predicted to be the RDS for CO formation on the h-In2O3(104) flat and step surfaces. On the h-In2O3(012) step surface and the h-In2O3(104) flat and step surfaces, the carbonate(carb-CO2*) as one of CO2 adsorption configurations can be seen as a spectator species at the Ov sites during the reaction, whereas on the h-In2O3(012) flat surface, protonation of the carb-CO2* contributes more to CO formation than protonation of the bt-CO2*. Meanwhile, the Ov sites on the h-In2O3(012) and h-In2O3(104) step surfaces show lower catalytic activities than corresponding flat surfaces, and thus they are predicted to play little role in determining the catalytic activity of the hexagonal In2O3 catalysts.

Self‐catalytic mechanism of prebiotic reactions: II. From urea and glycinamide to hypoxanthine

AbstractMechanisms of reactions for formylation of urea, leading to N,N′‐diformylurea, and for the dehydration of glycinamide and N,N′‐diformylurea, yielding hypoxanthine, are suggested. It is shown that these reactions are self‐catalyzed. The first is catalyzed by formic acid, while the second is catalyzed by N,N′‐diformylurea. The suggested reaction mechanism shows that the N3 and N9 atoms of hypoxanthine originate from urea in agreement with available 1H NMR experimental data by Lagoja and Herdewijn (Lagoja & Herdewijn, Chem. Biodiv. 2004, 1, 106). A complete reaction pathway of prebiotic reactions for formation of the hypoxanthine from urea, formic acid, and glycinamide in formamide, where formamide/formimidic acid plays the role of a proton‐carrying catalyst, is also suggested.

Tuning morphology, composition and oxygen reduction reaction (ORR) catalytic performance of manganese oxide particles fabricated by γ-radiation induced synthesis

A γ-radiation induced synthesis method is used to fabricate manganese oxide catalysts through both reduction and oxidation routes. It is shown that the morphology, composition and electrochemical performance of the produced manganese oxide particles can be tuned by altering the redox conditions. The catalysts prepared via radiolytic oxidation have a hollow spherical morphology, possess γ-MnO2 structure and show high catalytic activity for the complete four-electron reaction pathway of the oxygen reduction reaction (ORR) in alkaline electrolyte. Meanwhile, the catalysts synthesized via radiolytic reduction possess a rod-like morphology with a Mn3O4 bulk structure and favour the incomplete two-electron reaction pathway for ORR. The high catalytic activity of the manganese oxide synthesized via the oxidation route can be attributed to high electrochemical surface area and increased amount of Mn3+ on the surface as compared to those in the sample obtained via the reduction route.

Catalytic performance and reaction mechanism of an iron-loaded catalyst derived from blast furnace slag for the CO-SO2 reaction to produce sulfur

For realizing resource desulfurization and high-value sulfur recovery, an iron-loaded catalyst was prepared from steelmaking byproduct blast furnace slag to reduce SO2 to elemental sulfur with CO. SO2 conversion efficiency, sulfur selectivity, and sulfur yield were used to evaluate the catalyst behavior. The catalyst with 15wt.% Fe2O3 at 500 °C showed the best activity performance. The changes in the structure and active phase of the catalyst as well as the complete reaction pathway were explored. A series of in situ diffuse reflectance infrared Fourier transform spectroscopy experiments were used to study the adsorption and desorption processes of CO and SO2, and a large number of sulfates were formed on the catalyst surface after the reaction. Combined with the experimental performance, the strong adsorption of BFS and the production pathway of H2S were proposed. The prepared iron-loaded catalysts followed the redox mechanism and the COS intermediate mechanism in the reaction.

Kinetics of non-oxidative propane dehydrogenation on Cr2O3 and the nature of catalyst deactivation from first-principles simulations

As the global demand for propene (propylene) is increasing, classic commercial production processes are becoming unable to keep up. Non-oxidative dehydrogenation, although hitherto underutilised industrially, has been put forward as a viable and green alternative, which is already used in a few commercial processes. In this work, we present detailed first-principles calculations of this reaction over a chromium oxide catalyst, which is the cornerstone of the Catofin® process. A complete reaction pathway for the dehydrogenation of propane to propene and ultimately to propyne (methylacetylene) was considered. Cracking, which can yield C1 and C2 hydrocarbons, and the deactivation of the catalyst because of coking were also included and modelled. We used density functional theory calculations with the Hubbard model to study the structure of the involved intermediates, their adsorption and their interconversion to explain how chromium oxide catalysts facilitate this reaction and which processes cause their deactivation. We showed that the interaction of the hydrocarbons and molecular hydrogen with the catalytic surface is rather weak, resulting in low surface coverages, but increasing with multiple bonds present in hydrocarbons. Having constructed the potential energy surface with all the intermediates and the transition states linking them, we proposed a kinetic model for the reaction. Kinetic Monte Carlo simulations were performed at experimentally relevant temperatures (700–1000 °C), pressures (up to 10 bar) and inlet mixture compositions to study the kinetics of the reaction and discover the rate determining steps. As the reaction is highly endothermic, considerable conversions only occur at high temperatures. The accumulation of propene and propyne in the reaction mixture adversely affects the reaction rate and selectivity. Higher pressures increase the reaction rate but also increase the rate of coke formation, which poisons the catalyst. Deactivation of the catalyst has a strong temperature dependence and is caused by the accumulation of C∗ and CH3CC∗ on the surface, which are hard to remove even with hydrogen.

Oxygen Dependent Purine Lesions in Double-Stranded Oligodeoxynucleotides: Kinetic and Computational Studies Highlight the Mechanism for 5',8-Cyclopurine Formation.

The reaction of HO• radical with DNA is intensively studied both mechanistically and analytically for lesions formation. Several aspects related to the reaction paths of purine moieties with the formation of 5',8-cyclopurines (cPu), 8-oxopurines (8-oxo-Pu), and their relationship are not well understood. In this study, we investigated the reaction of HO• radical with a 21-mer double-stranded oligodeoxynucleotide (ds-ODNs) in γ-irradiated aqueous solutions under various oxygen concentrations and accurately quantified the six purine lesions (i.e., four cPu and two 8-oxo-Pu) by LC-MS/MS analysis using isotopomeric internal standards. In the absence of oxygen, 8-oxo-Pu lesions are only ∼4 times more than cPu lesions. By increasing oxygen concentration, the 8-oxo-Pu and the cPu gradually increase and decrease, respectively, reaching a gap of ∼130 times at 2.01 × 10-4 M of O2. Kinetic treatment of the data allows to estimate the C5' radical competition between cyclization and oxygen trapping in ds-ODNs, and lastly the rate constants of the four cyclization steps. Tailored computational studies by means of dispersion-corrected DFT calculations were performed on the CGC and TAT in their double-strand models for each cPu diastereoisomer along with the complete reaction pathways of the cyclization steps. Our findings reveal unheralded reaction mechanisms that resolve the long-standing issues with C5' radical cyclization in purine moieties of DNA sequences.

Computational Screening of Metal–Organic Framework-Supported Single-Atom Transition-Metal Catalysts for the Gas-Phase Hydrolysis of Nerve Agents

Recent studies have suggested that the gas-phase hydrolysis of nerve agents by Zr-based metal–organic frameworks (MOFs) may be limited by product inhibition resulting from strong bidentate binding of the hydrolysis products to the Zr6-nodes. A potential method to avoid this problem is to deposit single-atom catalysts on the nodes so that the products bind in a more favorable monodentate mode. Such catalytic active sites can be characterized with atomic precision, enabling detailed computational mechanistic studies. Thus, we used density functional theory to perform a comprehensive screening of single-atom transition-metal catalysts, in varying oxidation states, deposited on NU-1000 nodes for the gas-phase hydrolysis of the nerve agent sarin. By calculating the complete reaction pathways for M–NU-1000 systems, we discovered that the highest reaction barrier varies between catalysts, highlighting the need to consider more than a single reaction step when screening a large number of diverse materials. The si...