Catalytic CH4 Research Articles

Distributed electrified heating for efficient hydrogen production

This study introduces a distributed electrified heating approach that is able to innovate chemical engineering involving endothermic reactions. It enables rapid and uniform heating of gaseous reactants, facilitating efficient conversion and high product selectivity at specific equilibrium. Demonstrated in catalyst-free CH4 pyrolysis, this approach achieves stable production of H2 (530 g h−1 L reactor−1) and carbon nanotube/fibers through 100% conversion of high-throughput CH4 at 1150 °C, surpassing the results obtained from many complex metal catalysts and high-temperature technologies. Additionally, in catalytic CH4 dry reforming, the distributed electrified heating using metallic monolith with unmodified Ni/MgO catalyst washcoat showcased excellent CH4 and CO2 conversion rates, and syngas production capacity. This innovative heating approach eliminates the need for elongated reactor tubes and external furnaces, promising an energy-concentrated and ultra-compact reactor design significantly smaller than traditional industrial systems, marking a significant advance towards more sustainable and efficient chemical engineering society.

Chemical looping-based catalytic CH4 decomposition and successive coke gasification with CO2 on ordered mesoporous NiMCeOx (M = Co, Zr, La)

Highly ordered mesoporous NiLaCeOx mixed metal oxides were investigated as effective catalysts for the chemical looping-based dry reforming of methane (CH4) with carbon dioxide (CO2) (CL-DRM). This catalyst exhibited an excellent catalytic activity and stability in the decomposition of CH4 to form H2 with surface carbons subsequently activated by CO2 via reverse Boudouard reaction to form CO. Among the NiMCeOx catalysts with various promoter (M = Co, Zr, or La), the optimal NiLaCeOx catalyst preserved its original highly ordered mesoporous structures, leading to the higher dispersion of smaller Ni nanoparticles. This was attributed to the stronger Ni-Ce interactions facilitated by the La2O3 metal oxide promoter. The NiLaCeOx demonstrated a higher rate of H2 formation and successive CO production in the CL-DRM reaction, resulting in a H2/CO ratio above 1.0. Additionally, the NiLaCeOx catalyst exhibited superior structural stability over 5 cyclic CL-DRM reactions for CH4 decomposition (>85 %) and CO2 activation (>45 %), with minimal deposition of cokes.

Single-Atom Alloys Materials for CO2 and CH4 Catalytic Conversion.

The catalytic conversion of greenhouse gases CH4 and CO2 constitutes an effective approach for alleviating the greenhouse effect and generating valuable chemical products. However, the intricate molecular characteristics characterized by high symmetry and bond energies, coupled with the complexity of associated reactions, pose challenges for conventional catalysts to attain high activity, product selectivity, and enduring stability. Single-atom alloys (SAAs) materials, distinguished by their tunable composition and unique electronic structures, confer versatile physicochemical properties and modulable functionalities. In recent years, SAAs materials demonstrate pronounced advantages and expansive prospects in catalytic conversion of CH4 and CO2. This review begins by introducing the challenges entailed in catalytic conversion of CH4 and CO2 and the advantages offered by SAAs. Subsequently, the intricacies of synthesis strategies employed for SAAs are presented and characterization techniques and methodologies are introduced. The subsequent section furnishes a meticulous and inclusive overview of research endeavors concerning SAAs in CO2 catalytic conversion, CH4 conversion, and synergy CH4 and CO2 conversion. The particular emphasis is directed toward scrutinizing the intricate mechanisms underlying the influence of SAAs on reaction activity and product selectivity. Finally, insights are presented on the development and future challenges of SAAs in CH4 and CO2 conversion reactions.

Catalytic C[sbnd]H activation-initiated transdiannulation: An oxygen transfer route to ring-fluorinated tricyclic γ-lactones

Catalytic CH activation-initiated annulation reactions have emerged as a versatile strategy for the efficient construction of diverse ring structural units and complex cyclic molecules in synthetic chemistry. Herein, we describe a new Rh(III)-catalyzed CH activation-initiated transdiannulation reaction of N,N-dimethyl enaminones with gem-difluorocyclopropenes in the presence of H2O, enabling a facile and oxygen transfer access to ring-fluorinated tricyclic γ-lactones with a 6-5 ring-junction tetrasubstituted stereocenter. This approach features bond-forming/annulation efficiency, good functional group tolerance and complete regioselectivity, which may include a complex process consisting of Rh(III)-catalyzed C(sp2)H activation, cyclic alkene insertion, defluorinated ring-opening of gem-difluorocyclopropane, intramolecular oxygen transfer, intramolecular cyclization and oxidative hydration.

Simultaneous and Continuous Production of Carbon Nanotubes and Hydrogen by Catalytic CH4 Decomposition in a Pressurized Fluidized-Bed Reactor

Simultaneous and Continuous Production of Carbon Nanotubes and Hydrogen by Catalytic CH₄ Decomposition in a Pressurized Fluidized-Bed Reactor

Thermally stable Pd/CeO2@SiO2 with a core-shell structure for catalytic lean methane combustion.

Noble metal catalysts exhibit high catalytic activity in lean CH4 combustion at low temperatures. However, the high surface energy of noble metal nanoparticles makes them susceptible to deactivation due to migratory-aggregation during the catalytic process. Herein, a core-shell structure with a Pd/CeO2 core and a SiO2 shell (denoted as Pd/CeO2@SiO2) was designed and prepared to enhance the thermal stability for catalytic lean CH4 combustion. A series of characterization methods demonstrated the successful encapsulation of SiO2 and the modified thermal stability. The results of activity tests indicated that Pd/CeO2@SiO2 exhibited the optimal catalytic performance. After seven runs, Pd/CeO2@SiO2 achieved 90% conversion of CH4 at 385 °C compared to Pd/CeO2 at 440 °C. The remarkable catalytic performance was attributed to the synergistic effect of strengthened metal-support interactions and the core-shell structure. On the one hand, the migration and aggregation of Pd nanoparticles were limited due to the protection of the SiO2 shell layer. On the other hand, the SiO2 shell layer further enhanced the interactions between the Pd nanoparticles and CeO2, thus promoting the formation of PdxCe1-xO2-δ solid solutions and active oxygen species, which were beneficial for the improvement of the stability and redox capacity of the catalyst.

Site-targeted decoration of palladium nanocrystals for catalytic CH4 removal in lean-burn exhaust.

Site-targeted decoration of catalytic nanocrystals is essential for maximizing performance with minimal materials use. Here, we demonstrate successful, site-targeted decoration of palladium (Pd) nanocrystals with nickel (Ni) exclusively along crystal facet edges through the thermal decomposition of nickel carbonyl (Ni(CO)4) vapor. Strong interactions between carbon monoxide and Pd facet for passivation or between Ni(CO)4 and crystal facet edges resulted in selective Ni decoration at the nanocrystal edges. The Ni-decorated Pd nanocrystals exhibit superior catalytic performance for methane (CH4) removal in an oxygen-rich lean-burn exhaust atmosphere, requiring 10 times less Ni decoration than conventional Pd-Ni composite catalysts prepared by the wet impregnation method. The site-targeted decoration of nanocrystals introduced in this work offers an efficient and resource-minimizing strategy for enhanced catalytic applications.

Effect of porphyrin ligands on the catalytic CH4 oxidation activity of monocationic μ-nitrido-bridged iron porphyrinoid dimers by using H2O2 as an oxidant.

The μ-nitrido-bridged iron phthalocyanine homodimer is a potent molecule-based CH4 oxidation catalyst that can effectively oxidize chemically stable CH4 under mild reaction conditions in an acidic aqueous solution including an oxidant such as H2O2. The reactive intermediate is a high-valent iron-oxo species generated upon reaction with H2O2. However, a detailed comparison of the CH4 oxidation activity of the μ-nitrido-bridged iron phthalocyanine dimer with those of μ-nitrido-bridged iron porphyrinoid dimers containing one or two porphyrin ring(s) has not been yet reported, although porphyrins are the most important class of porphyrinoids. Herein, we compare the catalytic CH4 and CH3CH3 oxidation activities of a monocationic μ-nitrido-bridged iron porphyrin homodimer and a monocationic μ-nitrido-bridged heterodimer of an iron porphyrin and an iron phthalocyanine with those of a monocationic μ-nitrido-bridged iron phthalocyanine homodimer in an acidic aqueous solution containing H2O2 as an oxidant. It was demonstrated that the CH4 oxidation activities of monocationic μ-nitrido-bridged iron porphyrinoid dimers containing porphyrin ring(s) were much lower than that of a monocationic μ-nitrido-bridged iron phthalocyanine homodimer. These findings suggested that the difference in the electronic structure of the porphyrinoid rings of monocationic μ-nitrido-bridged iron porphyrinoid dimers strongly affected their catalytic light alkane oxidation activities.

Effect of Fe-loading in iron-based catalysts for the CH4 decomposition to H2 and nanocarbons

The catalytic CH4 decomposition (CMD) over Fe-based catalyst is an economical and environmentally friendly way to produce Cox-free H2 and carbon nanotubes (CNTs). The Fe-loading was varied to study its influence on the catalytic performance. The highest H2 yield (82.25%) was obtained with a 12% Fe content where the activity of the catalyst did not decrease for 3 h on-stream. A higher Fe content causes the Fe dispersion to decrease, resulting in a reduced available surface area of active sites. Different techniques were used to characterise the fresh and spent catalysts i.e., ICP-AES, XRD, H2-TPR, SEM, TEM, and Raman spectroscopy. Plotting kinetic results as a function of 1/T, defines two different conversion ranges, being reaction rate controlled at low temperature and diffusion rate controlled at high temperature. For the reaction rate controlled regime, the Arrhenius equation provides an activation energy of 101.26 kJ/mol (Ea) and a pre-exponential factor of 393 kmol/s (A).

Methane Catalytic Combustion under Lean Conditions over Pristine and Ir-Loaded La1-xSrxMnO3 Perovskites: Efficiency, Hysteresis, and Time-on-Stream and Thermal Aging Stabilities.

The increasing use of natural gas as an efficient, reliable, affordable, and cleaner energy source, compared with other fossil fuels, has brought the catalytic CH4 complete oxidation reaction into the spotlight as a simple and economic way to control the amount of unconverted methane escaping into the atmosphere. CH4 emissions are a major contributor to the 'greenhouse effect', and therefore, they need to be effectively reduced. Catalytic CH4 oxidation is a promising method that can be used for this purpose. Detailed studies of the activity, oxidative thermal aging, and the time-on-stream (TOS) stability of pristine La1-xSrxMnO3 perovskites (LSXM; X = % substitution of La with Sr = 0, 30, 50 and 70%) and iridium-loaded Ir/La1-xSrxMnO3 (Ir/LSXM) perovskite catalysts were conducted in a temperature range of 400-970 °C to achieve complete methane oxidation under excess oxygen (lean) conditions. The effect of X on the properties of the perovskites, and thus, their catalytic performance during heating/cooling cycles, was studied using samples that were subjected to various pretreatment conditions in order to gain an in-depth understanding of the structure-activity/stability correlations. Large (up to ca. 300 °C in terms of T50) inverted volcano-type differences in catalytic activity were found as a function of X, with the most active catalysts being those where X = 0%, and the least active were those where X = 50%. Inverse hysteresis phenomena (steady-state rate multiplicities) were revealed in heating/cooling cycles under reaction conditions, the occurrence of which was found to depend strongly on the employed catalyst pre-treatment (pre-reduction or pre-oxidation), while their shape and the loop amplitude were found to depend on X and the presence of Ir. All findings were consistently interpreted, which involved a two-term mechanistic model that utilized the synergy of Eley-Rideal and Mars-van Krevelen kinetics.

Catalytic CH4 pyrolysis promoted by the interface of a molten metal–salt hybrid system

Hydrogen is an important chemical feedstock and energy carrier. A promising idea for a bridging technology for net-zero carbon emission is the catalytic pyrolysis of natural gas into hydrogen and solid carbon. However, the activation of methane and recovery of the produced carbon with high purity are the main hurdles for process commercialization. In the present study, molten metal–salt layered reaction beds for methane pyrolysis were investigated to determine the effect of the interface and the optimal ratio of metal and salt. These layered catalyst beds had several advantages over pure molten metal or molten salt catalyst beds. First, the length of the molten metal layer could be minimized to a level where the methane bubbles only touch the metal–salt interface, enhancing the economic feasibility of the process. Second, the metal–salt interface could delay bubble rising in proportion to the interfacial tension. Third, the molten salt layer could wash out the residual metal traces from the produced carbon, improving the carbon purity. This study would provide hints for building economically viable catalytic pyrolysis of methane based on molten metal-salt layered reaction bed.

A combined production technology for ethylene and hydrogen with an ethane cracking center and dielectric barrier discharge plasma reactor

Dielectric barrier discharge (DBD) plasma technology for non-oxidative CH4 conversion is considered a promising alternative to fossil fuel-based thermochemical counterparts for ethylene production. Herein, we propose a combined production technology for ethylene and hydrogen using shale gas, which consists of an ethane cracking center (ECC) and a DBD plasma reactor. Our plasma-assisted catalytic CH4 conversion reaction facilitates the control of product selectivity by adjusting the particle size and enhances ethylene production compared to conventional ECCs. To demonstrate the economic feasibility of the proposed process, we evaluated 9 and 16 catalysts for direct and indirect ethylene production, respectively. The energy demand of the DBD plasma reactor was estimated using an equivalent electrical circuit model. Most importantly, the levelized costs of ethylene production are assessed by technoeconomic analysis associated with individual system components, based on the two different ethylene production strategies. Furthermore, sensitivity analysis showed a potential linkage with the electricity produced from a renewable energy system. The results of this analysis support the feasibility of the DBD plasma-assisted catalytic reaction process integrated with ECC for energy-efficient CH4-conversion into high-value products.

Asymmetric Low-Frequency Pulsed Strategy Enables Ultralong CO2 Reduction Stability and Controllable Product Selectivity.

Copper-based catalysts are widely explored in electrochemical CO2 reduction (CO2RR) because of their ability to convert CO2 into high-value-added multicarbon products. However, the poor stability and low selectivity limit the practical applications of these catalysts. Here, we proposed a simple and efficient asymmetric low-frequency pulsed strategy (ALPS) to significantly enhance the stability and the selectivity of the Cu-dimethylpyrazole complex Cu3(DMPz)3 catalyst in CO2RR. Under traditional potentiostatic conditions, Cu3(DMPz)3 exhibited poor CO2RR performance with the Faradaic efficiency (FE) of 34.5% for C2H4 and FE of 5.9% for CH4 as well as the low stability for less than 1 h. We optimized two distinguished ALPS methods toward CH4 and C2H4, correspondingly. The high selectivities of catalytic product CH4 (FECH4 = 80.3% and above 76.6% within 24 h) and C2H4 (FEC2H4 = 70.7% and above 66.8% within 24 h) can be obtained, respectively. The ultralong stability for 300 h (FECH4 > 60%) and 145 h (FEC2H4 > 50%) was also recorded with the ALPS method. Microscopy (HRTEM, SAED, and HAADF) measurements revealed that the ALPS method in situ generated and stabilized extremely dispersive and active Cu-based clusters (∼2.7 nm) from Cu3(DMPz)3. Meanwhile, ex situ spectroscopies (XPS, AES, and XANES) and in situ XANES indicated that this ALPS method modulated the Cu oxidation states, such as Cu(0 and I) with C2H4 selectivity and Cu(I and II) with CH4 selectivity. The mechanism under the ALPS methods was explored by in situ ATR-FTIR, in situ Raman, and DFT computation. The ALPS methods provide a new opportunity to boost the selectivity and stability of CO2RR.

Stacking of a Cofacially Stacked Iron Phthalocyanine Dimer on Graphite Achieved High Catalytic CH4 Oxidation Activity Comparable to That of pMMO.

Numerous biomimetic molecular catalysts inspired by methane monooxygenases (MMOs) that utilize iron or copper-oxo species as key intermediates have been developed. However, the catalytic methane oxidation activities of biomimetic molecule-based catalysts are still much lower than those of MMOs. Herein, we report that the close stacking of a μ-nitrido-bridged iron phthalocyanine dimer onto a graphite surface is effective in achieving high catalytic methane oxidation activity. The activity is almost 50 times higher than that of other potent molecule-based methane oxidation catalysts and comparable to those of certain MMOs, in an aqueous solution containing H2O2. It was demonstrated that the graphite-supported μ-nitrido-bridged iron phthalocyanine dimer oxidized methane, even at room temperature. Electrochemical investigation and density functional theory calculations suggested that the stacking of the catalyst onto graphite induced partial charge transfer from the reactive oxo species of the μ-nitrido-bridged iron phthalocyanine dimer and significantly lowered the singly occupied molecular orbital level, thereby facilitating electron transfer from methane to the catalyst in the proton-coupled electron-transfer process. The cofacially stacked structure is advantageous for stable adhesion of the catalyst molecule on the graphite surface in the oxidative reaction condition and for preventing decreases in the oxo-basicity and generation rate of the terminal iron-oxo species. We also demonstrated that the graphite-supported catalyst exhibited appreciably enhanced activity under photoirradiation owing to the photothermal effect.

Evaluation of CH4 oxidation activity of high-valent iron-oxo species of a μ-nitrido-bridged heterodimer of iron porphycene and iron phthalocyanine

Catalytic CH4 oxidation activity of a μ-nitrido-bridged heterodimer of an iron phthalocyanine and an iron porphycene in an aqueous solution containing excess H2O2 was examined.

Multidisciplinary green approaches (ultrasonic, co-precipitation, hydrothermal, and microwave) for fabrication and characterization of Erbium-promoted Ni-Al2O3 catalyst for CO2 methanation

The dispersion of nickel catalysts is crucial for the catalytic ability of CO2 methanation, which can be influenced by the fabrication method and the operation process of the catalysts. Therefore, a series of fabrication methods, including ultrasonic, hydrothermal, microwave, and co-precipitation, have been applied to prepare 25Ni-5Er-Al2O3 catalysts. The fabrication method can partially influence the structural and catalytic activity of the nickel aluminate catalysts. Among the catalysts modified by Erbium prepared with various methods, the catalyst fabricated by ultrasonic pathway exhibited better catalytic performance and CH4 selectivity especially, at a temperature (400 ℃). The impact of the temperature of the reaction (200–500 °C) was examined under a stoichiometric precursor ratio of (H2:CO2) = 4: 1, atmospheric pressure, and space velocity (GHSV) of 25000 mL/gcath. The results demonstrate that the ultrasonic method is strongly efficient for fabricating Ni-based catalysts with a high BET surface area of about 190.33 m2g−1. The catalyst composed via the ultrasonic technique has 69.38 % carbon dioxide conversion and 100 % methane selectivity at 400 °C for excellent catalytic performance in CO2 methanation reactions. The fabrication effect can be associated with its high surface area, which is achieved via the hot spot mechanism. Besides, the addition of Erbium promotes the Ni dispersion on the supports and stimulates the positive reaction because of the erbium oxygen vacancies.

Effect of the Rare Earth Metals (Tb, Nd, Dy) addition for the modification of nickel catalysts supported on alumina in CO2 Methanation

In the current research, a group of rare-earth metals functionalized mesoporous Ni-M/Al2O3 (M = Tb, Dy, Nd) composite oxides were prepared by the one-pot sonochemical pathway and applied in the CO2 methanation procedure. Promoters can partially influence the textural and catalytic characteristics of Ni–Al2O3 catalysts. Physicochemical characteristics of the as-fabricated catalysts were identified utilizing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDS), Temperature Programmed Reduction (H2-TPR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analyses. Among the specimens, the catalyst modified by Terbium (Tb) manifested better catalytic performance and CH4 selectivity, particularly at low temperatures (350–400 °C). The influence of reaction temperature (200–500 °C) was scrutinized below space velocity (GHSV) of 25,000 ml/gcath, atmospheric pressure, and stoichiometric ratio of CO2 to H2 (1: 4). The impact of the desired content of nickel and terbium was examined. The 25Ni–5Tb–Al2O3 operates the best function for CO2 methanation, which can attain the highest CO2 conversion of 66.93% at 400 °C at atmospheric pressure. The superior catalytic performance of 25Ni–5Tb–Al2O3 could be assigned to the appropriate fabrication method and the promotion effect of Terbium. The synthesis effect could be assigned to its large surface area, obtaining by the hot spot mechanism. The addition of Terbium promotes the Ni distribution on the supports as well as accelerates the positive reaction due to the oxygen vacancies of Terbium. Besides, these outcomes could be defined with the maximum distribution of active nickel sites on the catalyst and improvement in the catalyst reduction ability at low temperatures.

Investigation on the Reaction Mechanism of Methane Oxidation over MgAl2O4‐Supported Single‐Atom Catalyst Prepared at High Temperature

AbstractStability and reactivity of single‐atom catalysts (SACs) are the points of concern in catalysis, especially under the harsh conditions, such as at elevated temperatures in oxidizing conditions. Previous work showed that thermally stable Pt1 SAC supported on K‐modified MgAl2O4 prepared by a vapor‐phase self‐assembly mechanism (Pt1/K/MgAl2O4) showed better performance than a Pt/MgAl2O4 nanocatalyst in catalytic CH4 oxidation (Chem, 2022, 8, 731–748). However, the detailed reaction mechanism remains unclear, which preventing the further development of single‐atom catalysts for CH4 oxidation. Herein, the sintering resistance behaviour of the Pt1/K/MgAl2O4 catalyst, was investigated by means of density functional theory (DFT) calculations, and it was found that the catalytic CH4 oxidation takes place via the Mars‐van Krevelen (MvK) mechanism, similar to that on conventional oxides. This viewpoint is further verified by experiments. Additionally, other noble metals (Au, Ir and Ru) and alkali elements (Na and Cs) are also investigated and it is found that the alkali types also affect the catalytic performance. This work clarifies the reaction mechanism of CH4 oxidation on metal SAC supported on MgAl2O4 synthesized at high temperature, providing a chance to manipulate the performances of metal SAC in CH4 oxidation.

Mechanism of Coupling of Methylidene to Ethylene Ligands in Dimetallic Assemblies; Computational Investigation of a Model for a Key Step in Catalytic C1 Chemistry.

Methylidene complexes often couple to ethylene complexes, but the mechanistic insight is scant. The path by which two cations [(η5-C5H5)Re(NO)(PPh3)(═CH2)]+ (5+) transform (CH2Cl2/acetonitrile) to [(η5-C5H5)Re(NO)(PPh3)(H2C═CH2)]+ (6+) and [(η5-C5H5)Re(NO)(PPh3)(NCCH3)]+ is studied by density functional theory. Experiments provide a number of constraints such as the second-order rate in 5+; no prior ligand dissociation/exchange; a faster reaction of (S)-5+ with (S)-5+ than with (R)-5+ ("enantiomer self-recognition"). Although dirhenium dications with Re(μ-CH2)2Re cores represent energy minima, they are not accessible by 2 + 2 cycloadditions of 5+. Transition states leading to ReCH2CH2Re linkages are prohibitively high in energy. However, 5+ can give non-covalent SRe/SRe or SRe/RRe dimers with π interactions between the PPh3 ligands but long ReCH2···H2CRe and H2CRe···H2CRe distances (3.073-3.095 Å and 3.878-4.529 Å, respectively). In rate-determining steps, these afford [(η5-C5H5)Re(NO)(PPh3)(μ-η2:η2-H2C···CH2)(Ph3P)(ON)Re(η5-C5H5)]2+ (132+), in which one rhenium binds the bridging ethylene more tightly than the other (2.115-2.098 vs 2.431-2.486 Å to the centroid). In the SRe/RRe adduct, Dewar-Chatt-Duncanson optimization leads to unfavorable PPh3/PPh3 contacts. Ligand interactions are further dissected in the preceding transition states via component analyses, and ΔΔG‡ (1.2 kcal/mol, CH2Cl2) favors the SRe/SRe pathway, in accordance with the experiment. Acetonitrile then displaces 6+ from the more weakly bound rhenium of 132+. The formation of similar μ-H2C···CH2 intermediates is found to be rate-determining for varied coordinatively saturated M═CH2 species [M = Fe(d6)/Re(d4)/Ta(d2)], establishing generality and enhancing relevancy to catalytic CH4 and CO/H2 chemistry.

CH4 Activation over Perovskite Catalysts: True Density and Reactivity of Active Sites

The high thermal stability of perovskites has drawn attention toward their applications for catalytic CH4 activation and conversion, typically occurring at high temperatures. The reaction rates of perovskite catalysts for CH4 combustion, however, trail behind those of noble metal catalysts. Ways to optimize the performance of perovskite catalysts are destined to trial-and-error approaches unless their complex reconstructed surfaces are correlated with fundamental kinetic parameters. Discerning the intrinsic activity of surface catalytic sites and the density of those sites is crucial to rationally envision complex metal oxides with enhanced catalytic performance. The present work presents a detailed kinetic analysis of catalytic CH4 combustion over a set of seven perovskites (SrTiO3, SrZrO3, SrFeO3, LaFeO3, LaInO3, LaCoO3, LaMnO3) with various surface terminations. Steady-state isotopic transient kinetic analysis was employed to measure turnover frequency (TOF) and density of surface intermediates (N) under operando conditions. Top surface characterization elucidated performance-structure relationships between near-monolayer surface composition and intrinsic reactivity of the catalysts. By using a chemical etching procedure to expose Fe-sites at the top surface of LaFeO3 (LaFeO3,HNO3), its TOF was increased 4-fold, compared with the unmodified sample, although N on the surface of LaFeO3,HNO3 decreased. Density functional theory simulations corroborated that surface Fe-termination and La-Fe termination offer lower energetic barriers for CH4 activation when compared with La-termination. In general, surface reconstruction is shown as a tool to tune TOF and N to improve reaction rates. This work fills a gap in current kinetic studies of perovskites through a careful assessment and discussion of the density and intrinsic reactivity of active sites for methane combustion over well-characterized reconstructed perovskite surfaces.