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Catalytic conversion of carbon dioxide (CO2) into value‐added chemicals is of pivotal importance, well the cost of capturing CO2 from dilute atmosphere is super challenge. One promising strategy is combining the adsorption and transformation at one step, such as applying alkali solution that could selectively reduce carbonate (CO32−) as consequences of CO2 adsorption. Due to complexity of this system, the mechanistic details on controlling the hydrogenation have not been investigated in depth. Herein, Ru/TiO2 catalyst was applied as a probe to elucidate the mechanism of CO32− activation, in which with thermodynamic and kinetic investigations, a compact Langmuir‐Hinshelwood reaction model was established which suggests that the overall rate of CO32− hydrogenation was controlled by a specific C−O bond rupture elementary step within HCOO− and the Ru surface was mainly covered by CO32− or HCOO− at independent conditions. This assumption was further supported by negligible kinetic isotope effects (kH/kD≈1), similarity on reaction barriers of CO32− and HCOO− hydrogenation (ΔH≠hydr,Na2CO3 and ΔH≠hydr,HCOONa) and a non‐variation of entropy (ΔS≠hydr≈0). More interestingly, the alkalinity of the solution is certainly like a two sides in a sword and could facilitate the adsorption of CO2 while hold back catalysis during CO32− hydrogenation. [ABSTRACT FROM AUTHOR]

The advanced strategy using Lewis base‐boryl radicals (LBRs) has recently been proposed for the addition of alkyl substituents to the full‐carbon quaternary center of an organic molecule. However, as the rate‐determining step in the whole route, reaction rate constants of LBRs with substrates are extremely lacking. In this paper, 4‐dimethylaminopyridine (DMAP)‐BH2⋅ was selected as a representative of LBRs, and its reactions with six monochloro‐substituted substrates, including three methyl chlorobenzoates and three chlorinated acetanilides were studied in experiments and theoretical calculations. The bimolecular reaction rate constants, kq, were determined using laser flash photolysis approach. By comparing activation energies along the two addition pathways, we have clarified the rate‐determining step as the attacking to carbonyl oxygen instead of chlorine atom. Furthermore, noncovalent interaction (NCI) analyses on these substrates indicate that weak interactions, such as hydrogen‐bonding and van der Waals interactions, have significant influence on the reactivity of these substrates. Our study provides concrete clues to extend this synthetic strategy. [ABSTRACT FROM AUTHOR]

CO oxidation has been studied for more than a century; however, molecular-level understanding of its activation protocol and related intermediates remains elusive. Here, we present a unified mechanistic and kinetic picture of various electronic metal-support interactions within platinum-carbon catalysts via in situ spectroscopic/kinetic analyses and multi-scale simulations. Transient kinetic analysis and molecular dynamics simulations with a reactive force field provided a quantitative description of the competition between the oxygen association and oxygen dissociation mechanisms tuned by the interfacial charge distribution and CO coverage. Steady-state isotopic transient kinetic analysis and density functional theory calculations revealed a simultaneous shift in the rate-determining step (RDS) from O2 * dissociation to O* and CO* and O2 * and CO* association. A de novo strategy from the interfacial charge distribution to the reaction mechanism, kinetics/thermodynamics of RDS, and, ultimately, catalytic performance was developed to quantitatively map the above CO activation mechanism with an order-of-magnitude increase in reactivity. The proposed catalytic picture and de novo strategy are expected to prompt the development of theories and methodologies for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Photoconvertible fluorescent proteins (pcFPs) undergo a slow photochemical transformation when irradiated with blue light. Since their emission is shifted from green to red, pcFPs serve as convenient fusion tags in several cutting‐edge biological imaging technologies. Here, a pcFP termed the Least Evolved Ancestor (LEA) was used as a model system to determine the rate‐limiting step of photoconversion. Perdeuterated histidine residues were introduced by isotopic enrichment and chromophore content was monitored by absorbance. pH‐dependent photoconversion experiments were carried out by exposure to 405‐nm light followed by dark equilibration. The loss of green chromophore correlated well with the rise of red, and maximum photoconversion rates were observed at pH 6.5 (0.059 ± 0.001 min−1 for red color acquisition). The loss of green and the rise of red provided deuterium kinetic isotope effects (DKIEs) that were identical within error, 2.9 ± 0.9 and 3.8 ± 0.6, respectively. These data indicate that there is one rate‐determining step in the light reactions of photoconversion, and that CH bond cleavage occurs in the transition state of this step. We propose that these reactions are rate‐limited on the min time scale by the abstraction of a proton at the His62 beta‐carbon. A conformational intermediate such as a twisted or isomerized chromophore is proposed to slowly equilibrate in the dark to generate the red form. Additionally, His62 may shuttle protons to activate Glu211 to serve as a general base, while also facilitating beta‐elimination. This idea is supported by a recent X‐ray structure of methylated His62. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of nitrate offers an efficient solution to nitrate pollution and a sustainable strategy for ammonia generation. Cu and Fe bimetallic electrocatalysts exhibit excellent electrochemical reduction of nitrate (NO3RR) reactivity but the conventional preparation strategy is complex and time‐consuming and this reaction is still suffers from unsatisfied kinetic and unidentified mechanisms. Herein, in situ electrodeposition strategy is employed to induce Cu to modify the Fe active sites of iron‐based N‐doping carbon nanofiber electrode (Fe/Fe3C@NCNFs) during NO3RR in Cu‐contained nitrate solution. Benefiting from the synergistic effect between Cu and Fe sites of Cu─Fe/Fe3C@NCNFs electrode, superior activity of rate‐determining reaction (*NO3 to *NO2) and reduced energy barriers of the following deoxidation and hydrogenation steps are achieved. Compared with Fe/Fe3C@NCNFs‐500, the pseudo‐first‐order (PFO) rate constant for NO3RR by Cu─Fe/Fe3C@NCNFs demonstrates nearly two‐fold improvement with high current efficiencies over wide pH and voltage range. Furthermore, the maximum NO3─N removal capacity and N2 selectivity of Cu─Fe/Fe3C@NCNFs reach 15593.8 mg N g−1 Fe and ca. 92% after twenty cycles. This work offers an avenue for highly active bimetallic electrode design, paving more insights into the interactions between active site construction and NO3RR performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A universal and scalable method is developed for recycling spent lithium batteries. • The mechanism on selective sulfidation of NCM is elucidated by DFT and experiments. • The regenerated· NCM· materials exhibit excellent electrochemical performance. • In situ XRD reveals the evolution process of transition metal sulfides into NCM. Traditional cathode recycling methods have become outdated amid growing concerns for high-value output and environmental friendliness in spent Li-ion battery (LIB) recycling. Our study presents a closed-loop approach that involves selective sulfurization roasting, water leaching, and regeneration, efficiently transforming spent ternary Li batteries (i.e., NCM) into high-performance cathode materials. By combining experimental investigations with density functional theory (DFT) calculations, we elucidate the mechanisms within the NCM-C-S roasting system, providing a theoretical foundation for selective sulfidation. Utilizing in situ X-ray diffraction techniques and a series of consecutive experiments, the study meticulously tracks the evolution of regenerating cathode materials that use transition metal sulfides as their primary raw materials. The Li-rich regenerated NCM exhibits exceptional electrochemical performance, including long-term cycling, high-rate capabilities, reversibility, and stability. The closed-loop approach highlights the sustainability and environmental friendliness of this recycling process, with potential applications in other cathode materials, such as LiCoO 2 and LiMn 2 O 4. Compared with traditional methods, this short process approach avoids the complexity of leaching, solvent extraction, and reverse extraction, significantly increasing metal utilization and Li recovery rates while reducing pollution and resource waste. [ABSTRACT FROM AUTHOR]

This work focuses on the comparison of H2 evolution in the hydrolysis of boron-containing hydrides (NaBH4, NH3BH3, and (CH2NH2BH3)2) over the Co metal catalyst and the Co3O4-based catalysts. The Co3O4 catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co3O4 under the action of weaker reducers (NH3BH3, (CH2NH2BH3)2). The high activity of Co3O4 has been previously associated with its reduced states (nanosized CoBn). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H2, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co3O4 structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D2O, as well as DFT modeling, reveal differences in water activation between Co and Co3O4-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation. [ABSTRACT FROM AUTHOR]

The present application note summarizes an advanced methodology that allows for deriving potential‐dependent volcano curves for energy storage and conversion processes. The conventional approach relies on the combination of density functional theory calculations and scaling relations for a single mechanistic pathway as well as a discussion of electrocatalytic activity by means of the potential‐determining step, determined at the equilibrium potential of the reaction. Herein, it is illustrated how several reaction mechanisms can be factored into the volcano curve and how the rate‐determining step based on the descriptor Gmax(U) can be derived by a rigorous thermodynamic analysis of adsorption free energies fed by a data‐inspired methodology. [ABSTRACT FROM AUTHOR]

Recovery of alumina from kaolinite presents a sustainable alternative to its recovery from bauxite, a major source of alumina which is depleting in quantity globally. Owhe kaolinite proves to be a reliable resource for this process given its rich alumina content. This study focused on the leaching of alumina from Owhe kaolinite in hydrochloric acid (HCl) solution. Effects of parameters such as acid concentration, stirring rate, leaching temperature, particle diameter and solid/liquid (S/L) ratio, were investigated. The experimental data was analyzed using relevant kinetic models to establish the best model of fit. Alumina leaching rate increased as the temperature, stirring rate, and acid concentration increased, and decreased with increase in solid/liquid ratio and particle diameter. The experimental results fitted into the solid film diffusion model while chemical reaction was found to be the rate-determining step, with activation energy (Ea) of 34.79 kJ/mol and a pre-exponential factor of 120.37 s–1. The result revealed an average alumina leaching rate of 85 % with an overall reaction constant of 0.983 s–1. Post-leaching analysis by energy dispersive spectrophotometer (EDS) also confirms over 80 % alumina leaching rate, which is in line with the experimental result. Hence, hydrochloric acid proved to be a viable lixiviant for alumina recovery from Owhe kaolinite.

The mixed ionic and electronic oxide LaNi0.6Fe0.4O3−δ (LNF) is a promising ceramic cathode material for solid oxide fuel cells. Since the reaction rate of oxygen interaction with the cathode material is extremely important, the present work considers the oxygen exchange mechanism between O2 and LNF oxide. The kinetic dependence of the oxygen/oxide interaction has been determined by two isotopic methods using 18O-labelled oxygen. The application of the isotope exchange with the gas phase equilibrium (IE-GPE) and the pulsed isotope exchange (PIE) has provided information over a wide range of temperatures (350–800 °C) and oxygen pressures (10–200 mbar), as each method has different applicability limits. Applying mathematical models to treat the kinetic relationships, the oxygen exchange rate (rH, atom × cm−2 × s−1) and the diffusion coefficient (D, cm2/s) were calculated. The values of rH and D depend on both temperature and oxygen pressure. The activation energy of the surface exchange rate is 0.73 ± 0.05 eV for the PIE method at 200 mbar, and 0.48 ± 0.02 eV for the IE-GPE method at 10–20 mbar; for the diffusion coefficient, the activation energy equals 0.62 ± 0.01 eV at 10–20 mbar for the IE-GPE method. Differences in the mechanism of oxygen exchange and diffusion on dense and powder samples are observed due to the different microstructure and surface morphology of the samples. The influence of oxygen pressure on the ratio of contributions of different exchange types to the total oxygen exchange rate is demonstrated. For the first time, the rate-determining step in the oxygen exchange process for LNF material has been identified. This paper discusses the reasons for the difference in the mechanisms of oxygen exchange and diffusion. [ABSTRACT FROM AUTHOR]

The development of cost‐efficient Pt‐group metals (PGM)‐based electrocatalysts with low noble metal loading for alkaline hydrogen oxidation reaction (HOR) remains challenging for practical applications of anion exchange membrane fuel cells (AEMFCs). Here we successfully synthesized a series of (RhxNi1−x)2P catalysts with satisfying HOR performance in alkaline media. Especially, (Rh0.3Ni0.7)2P−C exhibits an excellent mass activity of 1.274 mA μgPGM−1, 7‐times higher than that of Rh−C. Density functional theory (DFT) calculations and experimental results indicate that benefiting from the synergistic effect of Rh sites with Ni2P, the hydroxyl binding energy (OHBE) is enhanced on the optimized P sites of (RhxNi1−x)2P, which, together with the accelerated water desorption behavior derived from the downshifted d‐band center of Rh sites in (RhxNi1−x)2P, contributes to speeding up the water formation step and thus resulting in the translation of rate‐determining step, as well as the enhanced alkaline HOR performance. [ABSTRACT FROM AUTHOR]

Bi-molecule of C 6 H 12 were found to be involved in C–H/C–C bond ruptures in C 6 H 12 oxidation catalyzed by Ce(OH)SO 4 · x H 2 O. And probably both the C–H bond rupture and the C–C bond cleavage were controlled by the elementary step(s) of C–H bond rupture. Considering the pressure/concentration dependence studies, a Langmuir-Hinshelwood model has been established to describe the whole reaction process. [Display omitted] • Ce(OH)SO 4 · x H 2 O achieved 77% KA oil selectivity at 10% C 6 H 12 conversion. • Bi-molecule of cyclohexane were proved to be involved in the C 6 H 12 oxidation. • C 6 H 10 O and ε-caprolactone are the key intermediates of the C–C bond rupture. Selective C–H bond oxidation of cyclohexane into KA oil (ketone-alcohol) is of vital importance in both fundamental research and industrial applications while limited by complex reaction network and suffering from low efficiency. In this study, Ce(OH)SO 4 · x H 2 O was chosen as a probe to systematically investigate the C–H bond activation and C–C bond rupture as a function of various reaction parameters, including the reactant/product concentrations, catalyst applied, reaction temperatures, acidic concentrations etc, and found that bi-molecule of C 6 H 12 was probably involved in both C–H bond rupture and C–C bond cleavage and both were controlled by one deprotonation elementary step with ·O 2 – and h + as the key active components, which were supported by parity fittings and primary KIEs determined. In addition, the C–C bond rupture was found to be mainly following C 6 H 10 O to ε-caprolactone and further to linear acids reaction path. Hopefully, this study could help people find/optimize reaction systems in selective hydrocarbon upgradings. [ABSTRACT FROM AUTHOR]

Ethylbenzene (EB) oxidation to oxygenated products catalyzed by carbon nanotubes (CNTs) and CNTs with confined cobalt nanoparticles (Co@C/CNTs) are conducted. Co@C/CNTs with enhanced interfacial charge transfer displays a unique activity. A kinetic model with the simplified network is established, in which seven elementary reactions with prominent features of EB oxidation are selected. The main parameters, reaction rate constant (k) and active energy (Ea) are obtained. Co@C/CNTs could speed up most elementary steps and reduce energy barriers, thus improving the overall activity. The homolytic cleavage of peroxide is confirmed to be the rate‐determining step (RDS). The k ratio (1.55) of acetophenone (AcPO)/1‐phenylethyl alcohol (PEA) is found to be close to the experimental result (rAcPO/rPEA, 1.30). The prediction of EB oxidation is simulated, showing that the synthesis of AcPO dominates the reaction route, while the addition of PEA would prohibit the reaction. [ABSTRACT FROM AUTHOR]

The electrocatalytic reduction of CO2 towards CO is one of the most desirable routines to reduce atmospheric CO2 concentration and maintain a global carbon balance. In this work, a novel porous NiCu-embedded ZIF-derived N-doped carbon nanoparticle (NiCu@NCNPs) catalyst has been identified as an active, highly selective, stable, and cost-effective catalyst in CO2 reduction. A CO selectivity as high as 100% has been achieved on NiCu@NCNPs which is the highest reported to date. The particle current density of CO on NiCu@NCNPs is around 15 mA cm–2 under the optimized potential at −0.9 V vs. RHE. The NiCu@NCNPs electrode also exhibits excellent stability during the five sequential CO2 electroreduction experiments. The superior catalytic performance of NiCu@NCNPs in CO2RR can be related to its microstructure with high electrochemical surface area and low electron transfer resistance. Furthermore, a kinetic analysis has shown the formation of intermediate *COOH is the rate-determining step in CO2RR towards CO. According to the results of density functional theory (DFT) calculations, a low Gibbs-free energy change (∆G) for the rate-determining step leads to the enhanced catalytic performance of CO2RR on NiCu@NCNPs. [ABSTRACT FROM AUTHOR]

Nitrogen chemisorption is a prerequisite for efficient ammonia synthesis under ambient conditions, but promoting this process remains a significant challenge. Here, by loading yttrium clusters onto a single-atom support, an electronic promoting effect is triggered to successfully eliminate the nitrogen chemisorption barrier and achieve highly efficient ammonia synthesis. Density functional theory calculations reveal that yttrium clusters with abundant electron orbitals can provide considerable electrons and greatly promote electron backdonation to the N2 antibonding orbitals, making the chemisorption process exothermic. Moreover, according to the "hot atom" mechanism, the energy released during exothermic N2 chemisorption would benefit subsequent N2 cleavage and hydrogenation, thereby dramatically reducing the energy barrier of the overall process. As expected, the proof-of-concept catalyst achieves a prominent NH3 yield rate of 48.1 µg·h−1·mg−1 at −0.2 V versus the reversible hydrogen electrode, with a Faradaic efficiency of up to 69.7%. This strategy overcomes one of the most serious obstacles for electrochemical ammonia synthesis, and provides a promising method for the development of catalysts with high catalytic activity and selectivity. [ABSTRACT FROM AUTHOR]

Studies of oxygen surface exchange kinetics for BaFeO 3– δ oxide were performed using the oxygen isotope exchange method with pulsed supply of an isotopically enriched mixture (PIE) at the partial oxygen pressure 21.3 kPa in the temperature range of 350–600 °С. Oxygen surface exchange kinetics was considered in the framework of two-step model including two consecutive steps: dissociative adsorption of oxygen and incorporation of oxygen adatoms into the crystal lattice of the oxide. The rates of oxygen heterogeneous exchange (r H), as well as the rates of dissociative adsorption (r a) and oxygen incorporation (r i), have been calculated. The process of oxygen dissociative adsorption at the surface of BaFeO 3– δ oxide was found to be the rate-determining step of the surface exchange. The appropriate models describing the oxygen exchange kinetics and possible mechanisms occurring in the system "gaseous oxygen – BaFeO 3– δ oxide" were discussed. [Display omitted] • The oxygen heterogeneous exchange rate is measured in BaFeO 3– δ oxide. • The rate-determining step of the oxygen exchange process is determined for BaFeO 3– δ. • Bonds breaking of the surface oxygen adatoms will limit oxygen exchange at BaFeO 3– δ surface. [ABSTRACT FROM AUTHOR]

PurposeTo derive the theoretical basis for the extended clearance model of organ elimination following both oral and IV dosing, and critically analyze the approaches previously taken.MethodsWe derived from first principles the theoretical basis for the extended clearance concept of organ elimination following both oral and IV dosing and critically analyzed previous approaches.ResultsWe point out a number of critical characteristics that have either been misinterpreted or not clearly presented in previously published treatments. First, the extended clearance concept is derived based on the well-stirred model. It is not appropriate to use alternative models of hepatic clearance. In analyzing equations, clearance terms are all intrinsic clearances, not total drug clearances. Flow and protein binding parameters should reflect blood measurements, not plasma values. In calculating the AUCR-factor following oral dosing, the AUC terms do not include flow parameters. We propose that calculations of AUCR may be a more useful approach to evaluate drug-drug and pharmacogenomic interactions than evaluating rate-determining steps. Through analyses of cerivastatin and fluvastatin interactions with cyclosporine we emphasize the need to characterize volume of distribution changes resulting from transporter inhibition/induction that can affect rate constants in PBPK models. Finally, we note that for oral doses, prediction of systemic and intrahepatic drug-drug interactions do not require knowledge of fu,H or Kp,uu for substrates/victims.ConclusionsThe extended clearance concept is a powerful tool to evaluate drug-drug interactions, pharmacogenomic and disease state variance but evaluating the AUCR-factor may provide a more valuable approach than characterizing rate-determining steps.

Tin-based materials have been designed as potential catalysts for the electrochemical conversion of CO 2 into a single product. However, such tin-based materials still face the challenges of unsatisfactory selectivity, because the rate-determining step is situated within the slow desorption step. In this work, a variety of tin-based materials are synthesized using the electrospinning technique in an effort to control the adsorption strength during electrochemical reduction, therefore improving the selectivity of CO 2 reduction toward formate. The optimized SnS material exhibits moderate adsorption strength to *OCHO and *HCOOH, and the appropriate atomic distance of Sn-Sn maintained the balanced adsorption posture of both intermediate. Therefore, the rate-determining step can be shifted from the slow desorption of the *HCOOH step (Sn) to the first hydrogenation of the *OCHO species step (SnS). Due to this shift, the SnS/C electrode demonstrated excellent selectivity, with a Faradaic efficiency of 96% for the production of formate. A maximum current density of -12.5 mA cm -2 for formate is also achieved for a period of 33 h., (© 2024 Wiley‐VCH GmbH.)

Catalytic conversion of carbon dioxide (CO 2 ) into value-added chemicals is of pivotal importance, well the cost of capturing CO 2 from dilute atmosphere is super challenge. One promising strategy is combining the adsorption and transformation at one step, such as applying alkali solution that could selectively reduce carbonate (CO 3 2- ) as consequences of CO 2 adsorption. Due to complexity of this system, the mechanistic details on controlling the hydrogenation have not been investigated in depth. Herein, Ru/TiO 2 catalyst was applied as a probe to elucidate the mechanism of CO 3 2- activation, in which with thermodynamic and kinetic investigations, a compact Langmuir-Hinshelwood reaction model was established which suggests that the overall rate of CO 3 2- hydrogenation was controlled by a specific C-O bond rupture elementary step within HCOO - and the Ru surface was mainly covered by CO 3 2- or HCOO - at independent conditions. This assumption was further supported by negligible kinetic isotope effects (k H /k D ≈1), similarity on reaction barriers of CO 3 2- and HCOO - hydrogenation (ΔH ≠ hydr,Na2CO3 and ΔH ≠ hydr,HCOONa ) and a non-variation of entropy (ΔS ≠ hydr ≈0). More interestingly, the alkalinity of the solution is certainly like a two sides in a sword and could facilitate the adsorption of CO 2 while hold back catalysis during CO 3 2- hydrogenation., (© 2024 Wiley-VCH GmbH.)

The electrocatalytic carbon dioxide or carbon monoxide reduction reaction (CO 2 RR or CORR) features a sustainable method for reducing carbon emissions and producing value-added chemicals. However, the generation of C 3 products with higher energy density and market values, such as n-propanol, remains highly challenging, which is attributed to the unclear formation mechanism of C 3+ versus C 2 products. In this work, by the Tafel slope analysis, electrolyte pH correlation exploration, and the kinetic analysis of CO partial pressure fitting, it is identified that both n-propanol and C 2 products share the same rate-determining step, which is the coupling of two C 1 intermediates via the derivation of the Butler-Volmer equation. In addition, inspired by the mechanistic study, it is proposed that a high OH ─ concentration and a water-limited environment are beneficial for promoting the subsequent *C 2 -*C 1 coupling to n-propanol. At 5.0 m [OH - ], the partial current density of producing n-propanol (j n-propanol ) reached 45 mA cm -2 , which is 35 and 1.3 times higher than that at 0.01 m [OH - ] and 1.0 m [OH - ], respectively. This study provides a comprehensive kinetic analysis of n-propanol production and suggests opportunities for designing new catalytic systems for promoting the C 3 production., (© 2024 Wiley‐VCH GmbH.)

Sluggish sulfur reduction reaction (SRR) kinetics remains a formidable challenge in Li–S electrochemistry. In this sense, the rational design of single‐atom species has become a burgeoning practice to expedite sulfur redox, where the underlying catalytic mechanism otherwise remains elusive. Herein, a class of metal single‐atom modified porous carbon nanofiber films (MSA PCNFs, M = Fe, Co, or Ni), fabricated via a generic synthetic strategy, as mediators to boost SRR kinetics is reported. Throughout electrokinetic measurement and operando instrumental probing, NiSA PCNF is evidenced to harness the catalytic superiority toward the rate‐determining step (i.e., liquid–solid conversion) of the SRR process. Density functional theory (DFT) simulations further reveal that the catalytic features of M–N–C moieties in catalyzing the Li2S precipitation rely heavily upon the coordination environments of adjacent carbon atoms and d‐orbital configurations of metal centers. In response, the thus‐derived S/NiSA PCNF cathode realizes an encouraging areal capacity of 14.12 mAh cm−2 under elevated sulfur loading (10.2 mg cm−2) and lean electrolyte usage (E/S ratio ≈ 5.5 μL mg−1). This work offers insight into the identification of exact catalytic moieties for different transition metal M–N–C single‐atom SRR mediators, showcasing a meaningful guidance and potential impact on Li–S catalysis. [ABSTRACT FROM AUTHOR]

Photo‐thermo catalysis utilizing light has been a promising strategy to improve the conventional thermal catalytic activity and attracts great attention nowadays. However, how heat works in synergy with light radiation is still unclear. This Concept article is trying to clarify the specific contents via summarizing the kinetic studies including 1) proposing elementary steps through pressure dependence studies, 2) estimating reaction barriers through measuring the apparent activation energies and 3) assigning the kinetically relevant step(s) with kinetic isotope effects (KIE) as well as 4) exploring the relationship of the reaction rate with the light excitation wavelength and light intensity. The challenges in kinetic studies such as describing the light‐induced carrier transfer process, the surface temperature under light illumination as well as reaction intermediates were discussed at the same time. Finally, an outlook about kinetic studies in clarifying the photo‐thermo catalysis reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The MgH 2 -VTiMn composite formed a core (VTiMn) −shell (MgH 2) structure. • High temperature led to the precipitation of some Mn in VTiMn as nanoscale α-Mn. • Rate-controlling step of the ab-/desorption process transitions at 598 K. • The hydrogen storage capacity decays linearly during cycling, with the kinetics becoming faster and then slower. To effectively enhance the hydrogen storage performance of MgH 2 , the multimetallic catalyst VTiMn was triumphantly synthesized by mechanical alloying, and the MgH 2 -10 wt% VTiMn composite was further fabricated. The results revealed that VTiMn significantly improved the thermodynamic, kinetics and cycle properties of MgH 2. Compared with pure MgH 2 , VTiMn promotes its plateau pressure to increase by 0.16 MPa and the initial desorption temperature to decrease by 47 K, showing obvious thermodynamic instability. Meanwhile, the MgH 2 -VTiMn composite can adsorb 5.5 wt% H 2 within 72 s and release within 1200 s at 523 K. The activation energies of hydrogen absorption and desorption are 30.1 and 90.5 kJ/mol, respectively. After 130 cycles at 598 K, 83 % hydrogen capacity retention can still be achieved. Characterisation indicated that the composite formed a core–shell structure with MgH 2 coated on the VTiMn surface. Part of the Mn element in VTiMn diffused into the Mg matrix, accompanied by the precipitation of nanoscale α-Mn particles at high temperature. The improved absorption kinetics can be attributed to the accelerated H atoms diffusion by the microcracks in VTiMn and the phase boundaries provided by the nano-precipitated phase, while the desorption kinetics benefits from the promotion of Mg nucleation and growth by α-Mn. Due to the effect of temperature, the rate-determining steps of the hydrogen absorption and desorption process of the composite at 598 K change from H atoms diffusion and Mg nucleation growth to H atoms surface penetration, respectively. These findings will facilitate a more comprehensive understanding of multimetallic catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • F-1Cu/MCM-41 catalyst boosts CO 2 cycloaddition efficiency via synergistic catalysis. • Stable Cu+ in F-1Cu/MCM-41 acts as effective Lewis acid, key for CO 2 adduct selectivity. • Study reveals the pivotal role of Cu+ and F− in the CO 2 cycloaddition mechanism. • Catalyst maintains 99% yield for 150 h in continuous flow, showing industrial robustness. • Catalyst's low environmental impact and green metrics highlight sustainability potential. This study explores the catalytic efficacy of fluorine-modified 1 wt% copper oxide on MCM-41 (F-1Cu/MCM-41) in carbon dioxide cycloaddition reactions. It delves into reaction mechanisms, active sites, and the practical applicability of the catalyst. Comprehensive examination through in situ diffuse reflectance infrared Fourier transform spectroscopy and other analytical methods substantiated the role of halogen-modified mono-dispersed copper species in carbon dioxide activation and silicon hydroxide sites in epoxide activation, while underscoring the role of Lewis bases and Brønsted acids. Kinetic studies and density functional theory calculations pinpointed carbon dioxide activation as the pivotal step. Furthermore, the catalyst exhibited robust stability and efficiency in continuous flow experiments, sustaining a 99% selectivity towards cyclic carbonate over 150 h. An eco-friendly evaluation confirmed the sustainability of the process, emphasizing its minimal environmental footprint and high efficiency. These results establish fluorine-modified 1 wt% copper oxide on MCM-41 as a formidable candidate for industrial-scale cyclic carbonate production, due to its promising performance and sustainability. [ABSTRACT FROM AUTHOR]

The catalyst coking and production of undesired products during the transformation of propane into propylene have been the critical challenges in the on purpose approach of propylene production. The mechanism contributing to this challenge was theoretically investigated through the analysis of cracking reaction routes. The study carried out employed the use of a density functional theory and cluster approach in order to understand the reactions that promote coking of the catalyst and in the search for the kinetic and thermodynamic data of the reaction mechanism involved in the process over Cr2O3. The ratedetermining step and feasible route that easily promote the production of small hydrocarbons like ethylene, methane, and many others were identified. The study suggests Cr-site substitution or co-feeding of oxygen can aid in preventing deep dehydrogenation in the conversion of propane to propylene. This information will help in improving the Cr2O3 catalyst performance and further increase the production yield.

Catalyst‐controlled vinylogous aza‐MBH reactions of vinylcyclopentenone were performed, and it was found that the α‐adducts were exclusively obtained by DABCO‐catalysis, while the γ‐adducts were the major products by DMAP‐catalysis. We report here that the rate‐determining step of the DABCO‐catalyzed α‐selective reactions is the Mannich‐type C−C bond forming step, while that of the DMAP‐catalyzed γ‐selective reactions seems to be the β‐elimination step. [ABSTRACT FROM AUTHOR]

Sulfur-containing pollutants lead to reduced quality of end products and environmental problems. Mercaptans are one of those sulfur pollutants which not only are smelly and toxic but also have high corrosive property. Mercaptan catalytic oxidation is the most important method of oil production refining from mercaptan. Thus, cognition of the reaction kinetics and interrogation of effects of various factors on the process are of the most requirements of mercaptan removing units. Due to the inadequate efforts made on reaction kinetics determination of catalytic oxidation of light mercaptans available in liquefied petroleum gas (LPG), this study was done in this regards. First, rate-determining step (RDS) of reactions was determined by analyzing the experimental data obtained from the Merox unit. The experiments were carried out on a cobaltphthalocyanine liquid catalyst in a packed reactor. In order to better understand the process, design, and optimization, the kinetics were defined with respect to the limiting reaction. By investigating the effective parameters of the kinetics, it was determined that the mercaptide ion (RS-) confines the oxidation reaction rate and has the first order in the rate equation. Finally, optimal values were proposed for each of the parameters.

Perovskite oxides obtained from Ba1−xLaxFeO3−δ (BLF) are considered beneficial materials for electrodes of solid oxide fuel cells and oxygen permeation membranes because of their high oxygen permeability, which is a criterion of oxide ion (O2−)-electronic mixed conductivity. In this paper, the prime focus was to understand the oxygen permeation mechanism through surface exchange and bulk diffusion of the Ba0.5La0.5FeO3−δ (BLF55) sample. The permeated oxygen flux displayed higher than that of the typical mixed conductor La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF), which was explored simultaneously with corresponding oxygen chemical potentials employing an especial experimental setup. This study found that the surface exchange reaction on the oxygen-lean side was the rate-determining step (RDS) of the oxygen permeation below 800 °C, resulting from lower hole concentration on the oxygen-lean side surface. Enhancing the charge transfer from the surface oxygen by increasing hole concentration is a prime important strategy to improve the surface exchange reaction.

Water oxidation, an essential step in photosynthesis, has attracted intense research attention. Understanding the reaction pathways at the electrocatalyst/water interface is of great importance for the development of water oxidation catalysts. How the water is oxidized on the electrocatalyst surface by the positive charges is still an open question. This review summarizes current advances in studies on surface chemistry within the context of water oxidation, including the intermediates, reaction mechanisms, and their influences on the reaction kinetics. The Tafel analyses of some electrocatalysts and the rate-laws relative to charge consumption rates are also presented. Moreover, how the multiple charge transfer relies on the intermediate coverage and the accumulated charge numbers is outlined. Lastly, the intermediates and rate-determining steps on some water oxidation catalysts are discussed based on density functional theories. [ABSTRACT FROM AUTHOR]

The multimetallic sulfur‐framework catalytic site of biological nitrogenases allows the efficient conversion of dinitrogen (N2) to ammonia (NH3) under ambient conditions. Inspired by biological nitrogenases, a bimetallic sulfide material (FeWSx@FeWO4) was synthesized as a highly efficient N2 reduction (NRR) catalyst by sulfur substitution of the surface of FeWO4 nanoparticles. Thus prepared FeWSx@FeWO4 catalysts exhibit a relatively high NH3 production rate of 30.2 ug h−1 mg−1cat and a Faraday efficiency of 16.4 % at −0.45 V versus a reversible hydrogen electrode in a flow cell; these results have been confirmed via purified 15N2‐isotopic labeling experiments. In situ Raman spectra and hydrazine reduction kinetics analysis revealed that the reduction of undissociated hydrazine intermediates (M‐NH2‐NH2) on the surface of the bimetallic sulfide catalyst is the rate‐determing step for the NRR process. Therefore, this work can provide guidance for elucidating the structure–activity relationship of NRR catalysts. [ABSTRACT FROM AUTHOR]

• Kinetic analysis reveals mechanisms post rate-determining step for HMF production. • Slow-forming reaction intermediate quickly reacts with sugar/HMF, forming humins. • High sugar loading favors unselective bimolecular reactions, lowering HMF yield. • Determined activation energies suggest that high reaction temperature is preferable. • Semi-batch system afforded 74% HMF yield from 55 wt% fructose loading (aq. basis). The development of high-yielding catalytic systems is pivotal in biomass upgrading. However, the investigation of kinetics in these complex reaction systems is often highly challenging, especially when reactions leading to byproduct formation are obscured by a preceding, slow rate-determining step. In this work, we introduce a unique approach to kinetic analysis that enables the investigation of reactions occurring post rate-determining step. The technique was applied to the conversion of sugars to 5-hydroxymethylfurfural (HMF), an important platform molecule for sustainable chemical production. First, screening experiments were carried out to identify a catalytic solvent system that achieves a balance between solvent stability, HMF yield, and cost-effectiveness. Our kinetic analysis on the identified system reveals that the fructose reactant undergoes a rate-determining dehydration step to form an unstable reactive intermediate. This intermediate further reacts competitively with other reactive species, such as the hexose reactants or the HMF product, ultimately lowering the HMF selectivity. The calculated relative activation energies of these reactions post rate-determining step provide intuitive insights into the effects of temperature, co-existing reactive species, as well as the previously unexplained effect of feed concentration on HMF selectivity. Additionally, we propose a novel reaction strategy that significantly enhances HMF yield when compared to a traditional batch synthesis. Notably, a high HMF yield of 74 % was achieved with an extreme 55 wt% fructose loading on an aqueous basis (20 wt% loading on a total weight basis) in a low-boiling 80 wt% dioxane/water mixture using an HCl catalyst at 393 K. [ABSTRACT FROM AUTHOR]

We have systematically investigated mechanistic details of the CO methanation reaction over a supported Ru catalyst in an idealized H 2 -rich reformate gas mixture with low CO:H 2 ratio, employing isotope labelling techniques. From a comprehensive set of transient FTIR spectroscopy measurements, following the buildup / disappearance of different adsorbed species upon exchange of isotope marked reactants during reaction or during desorption, we derive that under these conditions the reaction is dominated by an associative reaction pathway, involving first the formation of adsorbed formyl intermediates, followed by hydrogenation of these intermediates and C-O bond breaking. Formate formation can be excluded. Measurements of kinetic isotope effects (KIEs) revealed a weak secondary inverse KIE with values of r CH4 /r CD4 between 0.6 (175 °C) and 1.0 (230 °C), indicating that at lower temperatures C-H bond formation, most likely HCO ad hydrogenation, is rate-determining, while at higher temperatures the reaction is increasingly controlled by C–O bond breaking. [Display omitted] • Ru/TiO 2 catalysts are highly active and selective for CO methanation at low T. • Reaction intermediates identified by transient isotope-exchange DRIFTS measurements. • Mechanism / RDS elucidated by transient DRIFTS and KIE measurements. • Reaction dominated by associative mechanism, with adsorbed formyl as intermediate. • RDS: formyl hydrogenation at low and C-O dissociation at high temperatures. [ABSTRACT FROM AUTHOR]

Activation of high-energy triple-bonds of N2 is the most significant bottleneck of ammonia synthesis under ambient conditions. Here, by importing cobalt single clusters as strong electron-donating promoter into the catalyst, the rate-determining step of ammonia synthesis is altered to the subsequent proton addition so that the barrier of N2 dissociation can be successfully overcome. As revealed by density functional theory calculations, the N2 dissociation becomes exothermic over the cobalt single cluster upon the strong electron backdonation from metal to the N2 antibonding orbitals. The energy barrier of the positively shifted rate-determining step is also greatly reduced. At the same time, advanced sampling molecular dynamics simulations indicate a barrier-less process of the N2 approaching the active sites that greatly facilitates the mass transfer. With suitable thermodynamic and dynamic property, a high ammonia yield rate of 76.2 μg h–1 mg |$^{-1 }_{\rm cat.}$| and superior Faradaic efficiency of 52.9% were simultaneously achieved. [ABSTRACT FROM AUTHOR]

Oxygen transport in ceramic oxide materials has been actively explored over the past decades. This is due to the desire to design high-temperature electrochemical devices for energy conversion. The research of oxygen transport is connected with necessity in understanding of processes proceeding between oxide materials and oxygen of gas phase. It is known that some functional parts of electrochemical devices have porous structure. Known methods for analyzing the kinetic interaction of oxygen in the gas phase and oxygen oxide, such as the use of 18O-labeled oxygen, are not always applicable for the study of porous materials. The paper shows the applicability of the isotope exchange method with the gas phase analysis to investigate porous ceramic materials using the La0.6Sr0.4MnO3–δ catalytic materials for oxygen reduction reaction. These measurements were taken in situ on materials with different porosity at temperature 800 °C and oxygen pressure 0.67 kPa. This paper shows the relationship between the intrinsic heterogeneous exchange rate (rH) and oxygen diffusion coefficient (D), and the effective apparent values obtained on the porous sample. [ABSTRACT FROM AUTHOR]

Photoconvertible fluorescent proteins (pcFPs) undergo a slow photochemical transformation when irradiated with blue light. Since their emission is shifted from green to red, pcFPs serve as convenient fusion tags in several cutting-edge biological imaging technologies. Here, a pcFP termed the Least Evolved Ancestor (LEA) was used as a model system to determine the rate-limiting step of photoconversion. Perdeuterated histidine residues were introduced by isotopic enrichment and chromophore content was monitored by absorbance. pH-dependent photoconversion experiments were carried out by exposure to 405-nm light followed by dark equilibration. The loss of green chromophore correlated well with the rise of red, and maximum photoconversion rates were observed at pH 6.5 (0.059 ± 0.001 min -1 for red color acquisition). The loss of green and the rise of red provided deuterium kinetic isotope effects (DKIEs) that were identical within error, 2.9 ± 0.9 and 3.8 ± 0.6, respectively. These data indicate that there is one rate-determining step in the light reactions of photoconversion, and that CH bond cleavage occurs in the transition state of this step. We propose that these reactions are rate-limited on the min time scale by the abstraction of a proton at the His62 beta-carbon. A conformational intermediate such as a twisted or isomerized chromophore is proposed to slowly equilibrate in the dark to generate the red form. Additionally, His62 may shuttle protons to activate Glu211 to serve as a general base, while also facilitating beta-elimination. This idea is supported by a recent X-ray structure of methylated His62., (© 2024 The Protein Society.)

Reduction of carbon dioxide (CO 2 ) by renewable electricity to produce multicarbon chemicals, such as ethylene (C 2 H 4 ), continues to be a challenge because of insufficient Faradaic efficiency, low production rates, and complex mechanistic pathways. Here, we report that the rate-determining steps (RDS) on common copper (Cu) surfaces diverge in CO 2 electroreduction, leading to distinct catalytic performances. Through a combination of experimental and computational studies, we reveal that C─C bond-making is the RDS on Cu(100), whereas the protonation of *CO with adsorbed water becomes rate-limiting on Cu(111) with a higher energy barrier. On an oxide-derived Cu(100)-dominant Cu catalyst, we reach a high C 2 H 4 Faradaic efficiency of 72%, partial current density of 359 mA cm -2 , and long-term stability exceeding 100 h at 500 mA cm -2 , greatly outperforming its Cu(111)-rich counterpart. We further demonstrate constant C 2 H 4 selectivity of >60% over 70 h in a membrane electrode assembly electrolyzer with a full-cell energy efficiency of 23.4%., Competing Interests: Competing interests statement:The authors declare no competing interest.

Summary: Understanding the mechanism of the alkaline hydrogen evolution reaction (HER) and finding a design principle to enhance the catalytic performance of electrocatalysts are of great significance in paving the way of alkaline water electrolysis. Here, taking cobalt phosphide (CoP) as a model material, we establish the alkaline HER activity trends as a function of a fundamental property, the proportion of the unoccupied 3d orbital (Pun). By doping CoP with a range of 3d and 4d transition metals with different Pun, we show that the intrinsic alkaline HER kinetics increases with Pun. DFT calculations indicate that the transition metals with higher Pun not only act as the oxophilic sites for enhanced water activation but also modulate the electronic structure of CoP to endow an optimized H adsorption (ΔG∗H). Moreover, by further comparing the correlation between water adsorption and dissociation or ΔG∗H and experimental alkaline HER activities, we find that water dissociation is the rate-determining step for alkaline HER.

In this study, LSM-YSZ composite cathodes were analyzed by changing the firing temperature, composition, and operating temperature to determine the contribution of each step of the oxygen reduction reaction (ORR). The overall resistance of the cathode reaction was characterized by fitting the AC impedance spectra with an equivalent circuit model. It was found that initial reactions of ORR (dissociative adsorption) are the main rate-determining step (RDS) regardless of operating or sintering temperature, while reactions on LSM surface become the main RDS when the ratio of LSM catalysts has a relatively small proportion. The [LSM-YSZ] 5:5 cathode fired at 1100 °C showed the best microstructure and lowest resistance in the ORR at an operating temperature of 700 °C (R HF : 0.18 Ωcm2, R MF : 0.20 Ω cm2, R LF : 0.25 Ωcm2, R cathode : 1.14 Ωcm2). This demonstrates the potential use of LSM-YSZ cathodes for IT/LT-SOFC without the use of expensive materials, such as LSCF and BSCF. [ABSTRACT FROM AUTHOR]

The chemical reaction between a graphite model edge and H 2 O is crucial in steam gasification. This study used density functional theory (DFT) calculations to systematically evaluate the reaction path of steam gasification. The research results indicate that a graphite model edge without active cites is more suitable for use as an initial model for steam gasification. The aromaticity of the graphite model edge and the desorption of CO are linearly related. H atoms from H 2 O are transferred to the graphite model edge, destroying the aromaticity of the edge carbon structure and facilitating the subsequent desorption process, which may be the cause of the higher reactivity of steam compared to CO 2 gasification. From a thermodynamic perspective, hydrogen transfer may be the rate-determining step of the overall reaction. The results of this paper can explain the kinetic differences in previous experiments that used water with varying isotopes of H (H 2 O vs D 2 O) and graphite in the gasification reaction (Yates and McKee, 1981; Mims and Pabst, 1987; Fletcher and Thomas, 2007). Our results provide new insights into the H transfer mechanism in steam gasification. [ABSTRACT FROM AUTHOR]

• H 2 generation from formic acid occurs via formate anion dehydrogenation pathway. • Sodium formate promotes the reaction rate by increasing formate anion concentration. • The charge of formate anion reduces the activation barrier of H-COO bond cleavage. • The rate-determining step is the combinative desorption of hydrogen. Efficient hydrogen production is one of the most important issues in the future energy economy. Dehydrogenation of formic acid has been extensively investigated for safe and easy hydrogen production. Thereby, various catalysts have been developed for aqueous formic acid dehydrogenation (FAD) reaction to efficiently produce hydrogen. However, there is still a lack of understanding of the reaction mechanism. Herein, to fundamentally comprehend the aqueous FAD reaction mechanism, we prepared Pd/C catalyst and performed controlled catalytic tests. The results demonstrated that the aqueous FAD reaction occurs through the formate anion dehydrogenation pathway. DFT calculation explained this by the observation that the charge of formate anion significantly mitigates the activation barrier of H-COO bond cleavage. In addition, computational prediction combined with kinetic isotope effect experiments verified that combinative desorption of hydrogen is the rate-determining step of FAD. [ABSTRACT FROM AUTHOR]

The reaction mechanism of HNCO with HO2 radicals is investigated by means of the B3PW91/6-311+G(d,p) method to determine a more reasonable pathway. Four possible entrance patterns are designed; however, only three situations are finally confirmed. When HNCO and HO2 are close to each other, they first form an intermediate a2. Then, the terminal O atom in HO2 connects with the C atom of HNCO along with the H atom transferring from HO2 to the O atom of HNCO. After that the C–O bond ruptures again to form i. Finally, product P6 (NCO + HOOH) is generated from i via H atom transfer. P6 is the most accessible product with the simplest steps and lowest barrier height. In addition, the energy of several of the routes is refined at the CCSD(T)/6-311+G(d,p) level based on the optimized geometries. Although there are some differences, the most favorable product is still P6. It is expected that this study would be helpful in further studies on HNCO and in understanding its reactions. [ABSTRACT FROM AUTHOR]

The electrochemical insertion patterns of potassium‐rich Prussian blue (PB) materials with different compositions and particle sizes were systematically compared, which allows us to deduce correlations between the influence of particle morphology and material structure on the potassium‐ion insertion mechanisms in aqueous solutions. Although structural analysis indicates that no first‐order phase transitions occur for nanosized K‐rich Prussian blue particles upon potassium‐ion (de)insertion, the electrochemical data (galvanostatic charge/discharge, cyclic voltammetry, small‐ and large‐amplitude potential step experiments) suggest other outcomes related to the two‐phase insertion mechanism for all explored PB samples. However, even in a case whereby the phase transformation is not accompanied by abrupt changes in the crystal structure, the two‐phase mechanism dominates all of the essential practical characteristics of performance of this cathode material, such as hysteresis (overpotential) between charge and discharge steps and the measured diffusivities of potassium‐ions during charge and discharge. The formalism presented herein provides a basis for quantitatively assessing ion insertion and deinsertion parameters unique to PB analogues. [ABSTRACT FROM AUTHOR]

The abundant asymmetric oxygen vacancies generated from mechanical ball milling strategy endow the BM-CuCe catalysts with excellent redox capability, allowing gaseous oxygen "easy come easy go", thereby resulting in the rate-determining steps transform into cracking of aromatic rings and the achievement of excellent toluene catalytic oxidation. [Display omitted] • Asymmetric oxygen vacancies were generated via facile ball-milling strategy. • The specific role of asymmetric oxygen vacancies was investigated. • Toluene removal efficiency was more than 90 % at 230 °C on BM-CuCe catalysts. • The possible degradation pathways of the reaction on three samples were revealed. Regulation of oxygen vacancy upon metal oxide catalysts is an effective strategy for improving the catalytic activity in the oxidation of volatile organic compounds. Herein, copper (Cu) ions were introduced into ceria (CeO 2) catalysts via the modulation of preparation methods (ball-milling, co-precipitation and sol-gel method) to generate asymmetric oxygen vacancies (AOVs) with varying concentrations at the Cu-CeO 2 interface, thereby enhancing the catalytic performance towards toluene. The presence of abundant AOVs promotes the rapid conversion of the redox couples of Ce4+/Ce3+ and Cu+/Cu2+ according to Cu+-O V -Ce3+ ↔ Cu2+- O (ad) 2- -Ce4+, enhancing the redox property and lattice oxygen mobility of the catalyst synthesized by ball-milling strategy (BM-CuCe). Moreover, the AOVs expedite the backfilling and activation of gaseous oxygen, leading to a transformation of rate-determining steps into the cracking of aromatic rings, significantly improving the catalytic activity towards toluene. The BM-CuCe catalyst, with the highest AOVs concentration, exhibits the excellent catalytic activity, water-resistance capability as well as stability. This work sheds light on the promoting effect of AOVs in the catalytic oxidation of toluene and contributes an attractive strategy for designing highly efficient metal oxide catalysts. [ABSTRACT FROM AUTHOR]