Electron Transfer Process Research Articles

Primary charge separation in Chloroflexus aurantiacus reaction centers at room temperature: ultrafast transient absorption measurements on QA-depleted preparations with native and chemically modified bacteriopheophytin composition.

The initial electron transfer (ET) processes in reaction centers (RCs) of Chloroflexus (Cfl.) aurantiacus were studied at 295K using femtosecond transient absorption (TA) difference spectroscopy. Particular attention was paid to the decay kinetics of the primary electron donor excited state (P*) and the formation/decay of the absorption band of the monomeric bacteriochlorophyll a anion (BA-) at ~ 1035nm, which reflects the dynamics of the charge-separated state P+BA-. It was found that in QA-depleted RCs containing native bacteriopheophytin a (BPheo) molecules at the HA and HB binding sites, the decay of P* to form the P+HA- state contains a fast (4 ps; relative amplitude 70%) and a slow (13 ps; relative amplitude 30%) kinetic components. The BA- absorption band at ~ 1035nm was detected only for the fast component. Based on global analysis of the TA data, the results are discussed in terms of the presence of two P* populations: in one, P* decays in 4 ps via a dominant two-step activationless P* → P+BA- → P+HA- ET with a contribution of 70% to the overall primary charge separation process, and in the other, P* decays in 13 ps via a one-step superexchange P* → P+HA- ET (contribution of 30%). Similar femtosecond TA measurements on QA-depleted-PheoA-modified RCs, in which the charge separation energetics was changed by replacing BPheo HA with plant pheophytin a, suggest the presence of a P* population where P+HA- formation can occur via a thermally activated two-step ET process.

Construction of low-toxicity cadmium sulfide/nitrogen-doped muti-walled carbon nanotubes for peroxymonosulfate activation: The crucial role of electron transfer.

Cadmium sulfide is widely employed in environmental catalysis due to its excellent catalytic behaviors. However, the inherent toxicity and leaching risk of CdS-based catalyst presents significant challenges for practical applications. This study explored the incorporation of CdS nanowires on the nitrogen-doped multi-wall carbon tubes (N-MWCNTs) substrate to minimize the leaching rate and mitigate the bio-toxicity by regulating the electron transfer process. The low bio-toxicity of CdS/NMWCNT was confirmed by s series of toxicity tests. Additionally, the catalytic performance could be further enhanced with the high conductivity under the interfacial inner-electronic field. Results showed that the TC (20mg/L) removal efficiency reached 90.31% within 30min by PMS activation. Moreover, the PMS activation process, unveiled by In-situ Raman, quenching tests, and EPR spectra, demonstrated the improved TC removal efficiency was ascribed to the dominated roles of •OH, SO4•- and O2•-. DFT calculations further conducted the "NMWCNT-CdS-PMS" electron transfer pathway, thus effective activating PMS and protecting the CdS from oxidation. The findings provide a theoretical basis for designing and synthesizing unstable metal catalysts for the removal of emerging organic contaminants from wastewater with PMS activation.

Advances and insights into modeling extracellular electron transfer in anaerobic bioprocesses.

Extracellular electron transfer (EET) plays an important role in maintaining redox balance in both natural and engineered anaerobic microbial systems, driving key biochemical processes such as energy generation, bioremediation, and waste degradation. While EET has been characterized in a limited number of microbes and applied in anaerobic digestion and bioelectrochemical systems, further research is needed to explore its mechanism across a broader range of microbial species and anaerobic processes. This review highlights advanced modeling frameworks that provide deeper insights into EET mechanisms and dynamics, aiming to optimize research efforts and minimize time and resource expenditure. Mechanistic models, encompassing thermodynamics and kinetics, are discussed for their utility in calculating conduction rates of electroactive microbes and assessing the energetics of medium chain carboxylic acids production. Genome-scale metabolic models are highlighted for elucidating the roles of cytochromes and conductive pili in the EET pathway. Machine learning is presented as a tool to improve model accuracy and predict EET mechanisms. Furthermore, the integration of quantum mechanics/molecular mechanics methods offers molecular-level insights into electron transfer, while quantum computing addresses limitations of classical computers by simulating complex electron transfer processes in multi-heme cytochromes. Developing advanced modeling techniques will complement experimental techniques, enabling precise predictions and optimization strategies for developing innovative and sustainable anaerobic biotechnologies.

Electrochemically Driven Selective Olefin Epoxidation by Cobalt-TAML Catalyst.

Epoxides are versatile chemical intermediates that are used in the manufacture of diversified industrial products. For decades, thermochemical conversion has long been employed as the primary synthetic route. However, it has several drawbacks, such as harsh and explosive operating conditions, as well as a significant greenhouse gas emissions problem. In this study, we propose an alternative electrocatalytic epoxidation reaction, using [CoIII(TAML)]- (TAML = tetraamido macrocyclic ligand) as a molecular catalyst. Under ambient conditions, the catalyst selectively epoxidized olefin substrates using water as the oxygen atom source, affording an efficient catalytic epoxidation of olefins with a broad substrate scope. Notably, [CoIII(TAML)]- achieved >60% Faradaic efficiency (FE) with >90% selectivity for cyclohexene epoxidation, which other heterogeneous electrocatalysts have never attained. Electrokinetic studies shed further light on the detailed mechanism of olefin epoxidation, which involved a rate-limiting proton-coupled electron transfer process, forming reactive cobalt oxygen active species embedded in 2e-oxidized TAML. Operando voltammetry-electrospray ionization mass spectrometry (VESI-MS) and electron paramagnetic resonance (EPR) analyses were utilized to identify a cobalt oxygen active intermediate during an electrocatalytic epoxidation by [CoIII(TAML)]-. Our findings offer a new possibility for sustainable chemical feedstock production using electrochemical methods.

Advanced Cathode Designs for High‐Energy Lithium/Sodium–Selenium Battery

AbstractSelenium, with its superior conductivity, serves as a promising cathode material in lithium–selenium (Li–Se) and sodium–selenium (Na–Se) batteries, exhibiting faster electron transfer processes and volumetric capacity. Nonetheless, challenges such as volume expansion, the shuttle effect, slow redox reaction kinetics, and the low conductivity of discharged products still hinder their commercial application. Extensive research has been conducted on the design and optimization of cathode materials to overcome these issues. This review summarizes the latest advancements in Se cathode design within Li/Na–Se systems, based on the electrochemical mechanisms of batteries and the origins of related challenges. The comprehensive design principle of advanced and stable selenium cathodes is put forward, the key role of carbon structure design is analyzed, and the strategies to improve the affinity of selenide and redox kinetics are discussed. Additionally, it introduces representative polymer‐based cathodes and metal–organic framework (MOF)‐based cathodes. Some potential modification strategies for active materials are also highlighted, including selenium sulfide composite cathodes and lithium selenide cathodes, which can significantly enhance the electrochemical mechanisms of Se‐based batteries. Finally, based on existing research, the related insights and directions for the future development of advanced Se cathodes are proposed.

Synthesis, Structure, and Redox Reactivity of Ni Complexes Bearing a Redox and Acid-Base Non-innocent Ligand with NiII, NiIII, and NiIV Formal Oxidation States.

A series of Ni complexes bearing a redox and acid-base noninnocent tetraamido macrocyclic ligand, H4-(TAML-4) {H4-(TAML-4) = 15,15-dimethyl-5,8,13,17-tetrahydro-5,8,13,17-tetraaza-dibenzo[a,g]cyclotridecene-6,7,14,16-tetraone}, with formal oxidation states of NiII, NiIII, and NiIV were synthesized and characterized structurally and spectroscopically. The X-ray crystallographic analysis of the Ni complexes revealed a square planar geometry, and the [Ni(TAML-4)] complex with the formal oxidation state of NiIV was characterized to be [NiIII(TAML-4•+)] with the oxidation state of the NiIII ion and the one-electron oxidized TAML-4 ligand, TAML-4•+. The NiIII oxidation state and the TAML-4 radical cation ligand, TAML-4•+, were supported by X-ray absorption spectroscopy and density functional theory calculations. The reversible interconversions between [NiII(TAML-4)]2- and [NiIII(TAML-4)]- and between [NiIII(TAML-4)]- and [NiIII(TAML-4•+)] were demonstrated in spectroelectrochemical measurements as well as in chemical oxidation and reduction reactions. The reactivities of [NiIII(TAML-4)]- and [NiIII(TAML-4•+)] were then investigated in hydride transfer reactions using NADH analogs. Hydride transfer from 9,10-dihydro-10-methylacridine (AcrH2) to [NiIII(TAML-4•+)] was found to proceed via electron transfer (ET) from AcrH2 to [NiIII(TAML-4•+)] with no deuterium kinetic isotope effect (kH/kD = 1.0(2)). In contrast, hydride transfer from AcrH2 to [NiIII(TAML-4)]- proceeded much more slowly via a concerted proton-coupled electron transfer (PCET) process with kH/kD = 7.0(5). In the latter reaction, an electron and a proton were transferred to the NiIII center and the TAML-4 ligand, respectively. The mechanisms of the ET by [NiIII(TAML-4•+)] and the concerted PCET by [NiIII(TAML-4)]- were ascribed to the different redox potentials of the Ni complexes.

Light-Driven Stepwise Reduction of Aliphatic Carboxylic Esters to Aldehydes and Alcohols.

The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate-catalyzed single electron transfer process and thiol-catalyzed hydrogen atom transfer process. The competitive back electron transfer process was effectively inhibited by protonation of the ketyl-type radical anion. This protocol enabled the efficient reduction of carboxylic esters to alcohols under mild conditions. By interruption of the reduction with prolinol, the step-controlled reduction of carboxylic esters to aldehydes was accomplished. The developed process was also successfully applied to the preparation of deuterated alcohols and aldehydes from esters with D2O as the deuterium source.

Light‐Driven Stepwise Reduction of Aliphatic Carboxylic Esters to Aldehydes and Alcohols

The reduction of carboxylic esters to aldehydes and alcohols is a fundamental functional group transformation in chemistry. However, the inertness of carbonyl group and the instability of ketyl radical anion intermediate impede the reduction of carboxylic esters via photochemical strategy. Herein, we described the reduction of aliphatic carboxylic esters with synergistic dual photocatalysis via phenolate‐catalyzed single electron transfer process and thiol‐catalyzed hydrogen atom transfer process. The competitive back electron transfer process was effectively inhibited by protonation of the ketyl‐type radical anion. This protocol enabled the efficient reduction of carboxylic esters to alcohols under mild conditions. By interruption of the reduction with prolinol, the step‐controlled reduction of carboxylic esters to aldehydes was accomplished. The developed process was also successfully applied to the preparation of deuterated alcohols and aldehydes from esters with D2O as the deuterium source.

Photoinduced energy and electron transfer processes in a supramolecular system combining a tetrapyrenylporphyrin derivative and arene-ruthenium metalla-prisms.

A supramolecular system, consisting of a tetrapyrenylporphyrinic core surrounded by arene-ruthenium prisms, has been assembled and characterized by means of electrochemical and photophysical techniques. The photophysical study shows that quantitative energy transfer from the peripheral pyrenyl units towards the central porphyrin core is operative in the tetrapyrenylporphyrinic system. Interestingly, encapsulation of the pyrenyl units into the ruthenium cages affects the photophysics of the central porphyrin component, since its emission quantum yield is reduced in the supramolecular array. Femtosecond transient absorption analysis evidenced a complex interplay of deactivation pathways, including energy and electron transfer processes from the porphyrin to the metalla-prisms, associated with different conformations of the system allowed by the flexibility of the linkers. Moreover, the non-emissive arene-ruthenium cages present a peculiar excited-state dynamics, here disentangled for the first time by means of transient absorption investigations.

Charge Capacitive Signatures at the Interface of E. coli/MOF Biohybrids to Create a Live Cell Biocapacitor.

The chemistry of the extracellular electron transfer (EET) process in microorganisms can be understood by interfacing them with abiotic materials that act as external redox mediators. These mediators capture and transfer extracellular electrons through redox reactions, bridging the microorganism and the electrode surface. Understanding this charge transfer process is essential for designing biocapacitors capable of modulating and storing charge signatures as capacitance at the electrode interface. Herein, a novel biointerfacial strategy is presented to investigate directional charge injection from a non-exoelectrogenic living microbe to an electrode surface using the porous metal-organic framework (MOF), MIL-88B. The biohybrid, formed by interfacing Escherichia coli (E. coli) with MIL-88B, demonstrates symbiotic interactions between the biotic and abiotic components, facilitating EET from E. coli to the electrode via the MOF. Acting as a redox mediator, the MOF catalyzes E. coli's exoelectrogenic activity, generating distinct charge capacitive signatures at the E. coli-MOF interface. This system integrates the capacitive signatures resulting from the EET process with the MOF's intrinsic pseudocapacitive properties and surface-controlled capacitive effects, functioning as a highly efficient biocapacitor. Furthermore, this approach of converting the biochemical energy of a non-exoelectrogenic microorganism into capacitive signatures opens a new pathway for translating biological signals into functional outputs, paving the way for autonomous biosensing platforms.

Dinitrogen Activation: A Novel Approach with P/B Intermolecular FLP.

This study explores the reactivity of a new intermolecular P/B frustrated Lewis pair in the context of dinitrogen activation through a push-pull mechanism. The ab initio molecular dynamics model known as atom-centered density matrix propagation plays a pivotal role in elucidating the weakly associated encounter complex. In-depth analysis, mainly through intrinsic reaction coordinate calculations, supports a single-step mechanism. Notably, N2 activation is observed to proceed through a concerted mechanism, proving slightly endergonic in solvents like toluene and hexane. Furthermore, density functional theory calculations reveal that the N2 activation reaction becomes kinetically and thermodynamically favorable when it is subjected to a moderately oriented external electric field of 2.57 V nm-1 along the reaction axis. In addition, natural bonding orbital and extended transition state-natural orbitals for chemical valence analyses contribute to a more profound comprehension of the electron-transfer processes integral to the chemical reaction.

Unraveling the Stoichiometric Interactions and Synergism between Ligand-Protected Gold Nanoparticles and Proteins.

Nanomaterials that engage in well-defined and tunable interactions with proteins are pivotal for the development of advanced applications. Achieving a precise molecular-level understanding of nano-bio interactions is essential for establishing these interactions. However, such an understanding remains challenging and elusive. Here, we identified stoichiometric interactions of water-soluble gold nanoparticles (Au NPs) with bovine serum albumin (BSA), unraveling their synergism in manipulating emission of nano-bio conjugates in the second near-infrared (NIR-II) regime. Using Au25(p-MBS)18 (p-MBS = para-mercaptobenzenesulfonic acid) as paradigm particles, we achieved precise binding of Au NPs to BSA with definitive molar ratios of 1:1 and 2:1, which is unambiguously evidenced by high-resolution mass spectrometry and transmission electron microscopy. Molecular dynamics simulations identified well-defined binding sites, mediated by electrostatic interactions and hydrogen bonds between the p-MBS moieties on the Au25(p-MBS)18 surface and BSA. Particularly, positively charged residues on BSA were found to be pivotal. By careful control of the molar ratio of Au25(p-MBS)18 to BSA, atomically precise [Au25(p-MBS)18]x-BSA conjugates (x = 1 or 2) could be formed. Through a comprehensive spectroscopy study, an electron transfer process and synergistic effect were manifested in the Au25(p-MBS)18-BSA conjugates, leading to drastically enhanced emission in the NIR-II window. This work offers insights into the precise engineering of nanomaterial-protein interactions and opens new avenues for the development of next-generation nano-bio conjugates for nanotheranostics.

Physical properties of chlorophyll–quinone conjugates prepared via Friedel–Crafts reaction

Pheophytin-a derivatives possessing plastoquinone and phylloquinone analogs in the peripheral 3-substituent were prepared by Friedel–Crafts reactions of a 3-hydroxymethyl-chlorin as one of the chlorophyll-a derivatives with benzo- and naphthohydroquinones, respectively, and successive oxidation of the 1,4-dihydroxy-aryl groups in the resulting dehydration products. The 3-quinonylmethyl-chlorins exhibited ultraviolet–visible absorption and circular dichroism spectra in acetonitrile, which were composed of those of the starting 3-hydroxymethyl-chlorin and the corresponding methylated benzo- and naphthoquinones. No intramolecular interaction between the chlorin and quinone π-systems was observed in the solution owing to the methylene spacer. The first reduction potentials of the quinone moieties in the synthetic conjugates were determined by cyclic voltammetry and shifted positively from those of the reference quinones. The former quinonyl groups were reduced more readily by approximately 0.1 V than the latter quinones, which was ascribable to the stabilization of the quinonyl anion radical by the nearby macrocyclic chlorin π-chromophore. This observation implied that the reduction potentials of quinones were regulated by the close pheophytin-a derivative by through-space interaction. Considering the charge shift from pheophytin-a anion radical to plastoquinone and phylloquinone in reaction centers of photosystems II and I, respectively, the reduction potentials of these quinones as a determinant factor of the rapid electron transfer process would be dependent on the pheophytin-a in the photosynthetic reaction centers of oxygenic phototrophs as well as on the neighboring peptides.

Effective One-for-All Phototheranostic Agent for Hypoxia-Tolerant NIR-II Fluorescent/PA Image-Guided Phototherapy.

Near-infrared (NIR)-triggered type-I photosensitizers are crucial to address the constraints of hypoxic tumor microenvironments in phototherapy; however, significant challenges remain. By selecting an electron-deficient unit, a matched energy gap in the upper-level state is instrumental in boosting the efficiency of intersystem crossing for the type-I electron transfer process. 2-Cyanothiazole, an electron acceptor, is covalently linked with N, N-diphenyl-4-(thiophen-2-yl)aniline to yield a multifunctional photosensitizer (TTNH) that exhibits intrinsic NIR absorbance and compatible T2 energy levels, facilitating both radiative and nonradiative transitions. The prepared nanoparticles (TTNH NPs) assembled from TTNH are activated by an 808nm laser and generated the O2•- for hypoxia-tolerant type-I photodynamic therapy under both normoxia and hypoxic conditions. TTNH NPs emitted NIR-II fluorescence with an impressive NIR-II fluorescence quantum yield of 2.08%. With a high photothermal conversion efficiency of 51.8% under 808nm laser stimulation, TTNH NPs exhibit photothermal therapy performance, accompanied by enhanced photoacoustic imaging capability owing to their strong NIR absorption. These characteristics make TTNH an effective NIR-wavelength-triggered phototheranostic agent that outperforms NIR-II fluorescence/photoacoustic dual-model imaging-guided type-I photodynamic therapy/photothermal therapy against hypoxic tumors. This results provide valuable insight for developing high-performance NIR-II-emissive superoxide radical phototheranostic agents.

Construction of an electrochemical sensor for the detection of methyl parathion with three-dimensional graphdiyne-carbon nanotubes.

To enhance the application performance of graphdiyne (GDY) in electrochemical sensing, carbon nanotubes (CNTs) were grown in situ to construct three-dimensional nanoarchitectures of GDY-CNTs composites. GDY-CNTs showed superior electrochemical properties and detection response to MP when compared withGDY, as the in situ growth of CNTs significantly increased the electrode surface area and enhanced the electron transfer process. GDY-CNTs were successfully used to construct electrochemical sensors for methyl parathion (MP). The proposed sensor exhibited a wide linear relationship for MP ranging from 0.09 to 64.6µM with a detection limit of 0.05µM. Moreover, the sensor also showed good stability and acceptable reproducibility, which provided a feasible method for rapid and accurate detection of MP in real samples. This work provides an effective application of graphdiyne in electrochemical sensing with constructed three-dimensional GDY-CNTs.

Theoretical study of the in situ formation of H2O2 by lytic polysaccharide monooxygenases: the reaction mechanism depends on the type of reductant.

Lytic polysaccharide monooxygenases (LPMOs) are a unique group of monocopper enzymes that exhibit remarkable ability to catalyze the oxidative cleavage of recalcitrant carbohydrate substrates, such as cellulose and chitin, by utilizing O2 or H2O2 as the oxygen source. One of the key challenges in understanding the catalytic mechanism of LPMOs lies in deciphering how they activate dioxygen using diverse reductants. To shed light on this intricate process, we conducted in-depth investigations using quantum mechanical/molecular mechanical (QM/MM) metadynamics simulations, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations. Specifically, our study focuses on elucidating the in situ formation mechanism of H2O2 by LPMOs in the presence of cellobiose dehydrogenase (CDH), a proposed natural reductant of LPMOs. Our findings reveal a proton-coupled electron transfer (PCET) process in generating the Cu(ii)-hydroperoxide intermediate from the Cu(ii)-superoxide intermediate. Subsequently, a direct proton transfer to the proximal oxygen of Cu(ii)-hydroperoxide results in the formation of H2O2 and LPMO-Cu(ii). Notably, this mechanism significantly differs from the LPMO/ascorbate system, where two hydrogen atom transfer reactions are responsible for generating H2O2 and LPMO-Cu(i). Based on our simulations, we propose a catalytic mechanism of LPMO in the presence of CDH and the polysaccharide substrate, which involves competitive binding of the substrate and CDH to the reduced LPMOs. While the CDH-bound LPMOs can activate dioxygen to generate H2O2, the substrate-bound LPMOs can employ the H2O2 generated from the LPMO/CDH system to perform the peroxygenase reactions of the polysaccharide substrate. Our work not only provides valuable insights into the reductant-dependent mechanisms of O2 activation in LPMOs but also holds implications for understanding the functions of these enzymes in their natural environment.

Visible Light-Induced Divergent Deoxygenation/Hydroxymethylation of Pyridine N-Oxides.

This study explores the deoxygenation of pyridine N-oxides and presents a one-step photoredox method for the direct synthesis of 2-hydroxymethylated pyridines from pyridine N-oxides. Mechanism studies elucidate the role of the catalyst and provide evidence of the possible electron transfer process and the formation of key radicals. A range of pyridine derivatives, particularly 2-hydroxymethyl-substituted pyridines, which may be difficult to obtain, can be synthesized in a single step.

Visible-Light-Induced Imine Hydrogenation Catalyzed by Thioxanthone-TfOH Complex.

Amino compounds are important molecules, commonly found in nature and widely applied in industrial production. Recently, photocatalysis has been discovered as an efficient method to synthesize amino compounds by promoting imine hydrogenation. In this work, a strategy of imine hydrogenation catalyzed by 2e- consecutive photoinduced electron transfer (ConPET) process of thioxanthone-TfOH complex (9-HTXTF) was thoroughly investigated with its reaction conditions optimized, substrate scope examined, and reaction mechanism elucidated, which provides an efficient method for synthesizing amino compounds.

Single-Atom-Induced Hybridization States Promote the Direct Trapping of Hot Carriers by Reactants for Photocatalysis.

Single-atom manipulation has emerged as an effective strategy for enhancing the photocatalytic efficiency. However, the mechanism of photogenerated carrier dynamics under single-atom modulation remains unclear. Combining first-principles calculations and non-adiabatic molecular dynamics simulations, we systematically studied carrier transfer and recombination in the oxygen reduction reaction of single-atom-doped C3N4 systems. Unlike the conventional two-step process, where single atoms trap photogenerated carriers before transferring them to reactants, our findings reveal a direct one-step electron transfer process, where single-atom-induced hybridization states facilitate the direct trapping of hot carriers by reactants from photocatalysts. Specifically, photogenerated electron transfer time through the one-step process is 237 and 325 fs for Sb and Cu single-atom-doped systems, respectively, considerably faster than the two-step process (hundreds of picoseconds). Moreover, these systems exhibit a nanosecond-level photogenerated carrier lifetime, driving a high photocatalytic efficiency. This study elucidates the carrier dynamics in single-atom photocatalysts, facilitating the screening of high-performance photocatalysts.

Direct Photocatalytic Oxidation of Methane to Formic Acid with High Selectivity via a Concerted Proton-Electron Transfer Process.

Light-driven direct conversion of methane to formic acid is a promising approach to convert methane to value-added chemicals and promote sustainability. However, this process remains challenging due to the complex requirements for multiple protons and electrons. Herein, we report the design of WO3-based photocatalysts modified with Pt active sites to address this challenge. We demonstrate that modulating the dimensional effect of Pt on the WO3 support is key to enhancing the catalytic performance of selective CH4-to-HCOOH conversion. The Pt nanoparticles on WO3 exhibit superior conversion rate, selectivity and durability in the production of HCOOH compared to the Pt-free sample and WO3 decorated with Pt single atoms. The optimal PtNPs-WO3 catalyst achieves a HCOOH conversion rate of 17.7 mmol g-1, with 84% selectivity and stability maintained for up to 48 h. Mechanistic studies show that the protonation of O2 to hydroxyl radicals is the limiting step for HCOOH yield. Pt nanoparticles can facilitate electron transfer and promote O2 dissociation, generating hydroxyl radicals via a proton-coupled electron transfer process. This process provides sufficient protons to lower the formation barrier for •OH radicals, thereby promoting the activation of CH4. In addition, Pt nanoparticles regulate the adsorption of oxygenated hydrocarbon intermediates, increasing the selectivity of the reaction. This work advances our understanding of catalyst design for methane conversion and the effective regulation of complex reaction pathways.