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Efficiently converting methane into valuable chemicals via photocatalysis under mild condition represents a sustainable route to energy storage and value‐added manufacture. Despite continued interest in this area, the achievements have been overshadowed by the absence of standardized protocols for conducting photocatalytic methane oxidation experiments as well as evaluating the corresponding performance. In this review, we present a structured solution aimed at addressing these challenges. Firstly, we introduce the norms underlying reactor design and outline various configurations in the gas–solid and gas–solid–liquid reaction systems. This discussion helps choosing the suitable reactors for methane conversion experiments. Subsequently, we offer a comprehensive step‐by‐step protocol applicable to diverse methane‐conversion reactions. Emphasizing meticulous verification and accurate quantification of the products, this protocol highlights the significance of mitigating contamination sources and selecting appropriate detection methods. Lastly, we propose the standardized performance metrics crucial for evaluating photocatalytic methane conversion. By defining these metrics, the community could obtain the consensus of assessing the performance across different studies. Moving forward, the future of photocatalytic methane conversion necessitates further refinement of stringent experimental standards and evaluation criteria. Moreover, development of scalable reactor is essential to facilitate the transition from laboratory proof‐of‐concept to potentially industrial production. [ABSTRACT FROM AUTHOR]

In the past, Cu‐oxo or ‐hydroxy clusters hosted in zeolites have been suggested to enable the selective conversion of methane to methanol, but the impact of the active site's stoichiometry and structure on methanol production is still poorly understood. Herein, we apply theoretical modeling in conjunction with experiments to study the impact of these two factors on partial methane oxidation in the Cu‐exchanged zeolite SSZ‐13. Phase diagrams developed from first‐principles suggest that Cu‐hydroxy or Cu‐oxo dimers are stabilized when O2 or N2O are used to activate the catalyst, respectively. We confirm these predictions experimentally and determine that in a stepwise conversion process, Cu‐oxo dimers can convert twice as much methane to methanol compared to Cu‐hydroxyl dimers. Our theoretical models rationalize how Cu‐di‐oxo dimers can convert up to two methane molecules to methanol, while Cu‐di‐hydroxyl dimers can convert only one methane molecule to methanol per catalytic cycle. These findings imply that in Cu clusters, at least one oxo group or two hydroxyl groups are needed to convert one methane molecule to methanol per cycle. This simple structure–activity relationship allows to intuitively understand the potential of small oxygenated or hydroxylated transition metal clusters to convert methane to methanol. [ABSTRACT FROM AUTHOR]

Molecular Dynamics (MD) simulations constitute a powerful tool that provides a 3D perspective of the dynamical behavior of chemical systems. Herein the first MD study of the dynamics of a catalytic organometallic system, in micellar media, is presented. The challenging methane catalytic functionalization into ethyl propionate through a silver‐catalyzed process has been targeted as the case study. The intimate nature of the micelles formed with the surfactants sodium dodecylsulfate (SDS) and potassium perfluorooctane sulfonate (PFOS) has been ascertained, as well as the relative distribution of the main actors in this transformation, namely methane, the diazo reagent and the silver catalyst, the latter in two different forms: the initial compound and a silver‐carbene intermediate. Catalyst deactivation occurs with halide containing surfactants dodecyltrimethylammonium chloride (DTAC) and Triton X‐100. Computed simulations allow explaining the experimental results, indicating that micelles behave differently regarding the degree of accumulation and the local distribution of the reactants and their effect in the molecular collisions leading to net reaction. [ABSTRACT FROM AUTHOR]

Pyridine oximes produced from aldehyde or ketone with hydroxylamine (NH2OH) have been widely applied in pharmaceutics, enzymatic and sterilization. However, the important raw material NH2OH exhibits corrosive and unstable properties, leading to substantial energy consumption during storage and transportation. Herein, this work presents a novel method for directly synthesizing highly valuable pyridine oximes using in situ generated NH2OH from electrocatalytic NO reduction with well‐design nanofiber membranes (Al‐NFM) derived from NH2‐MIL‐53(Al). Particularly, 2‐pyridinealdoxime, the precursor of antidote pralidoxime (2‐PAM) for nerve agents suffering from scarcity and high cost, was achieved with a Faraday efficiency up to 49.8 % and a yield of 92.1 %, attributing to the high selectivity of NH2OH production on Al‐NFM, further easily reacted with iodomethane to produce 2‐PAM. This study proposes a creative approach, having wide universality for synthesizing pyridine and other oximes with a range of functional groups, which not only facilitates the conversion of exhaust gas (NO) and waste water (NO2−) into valuable chemicals especially NH2OH production and in situ utilization through electrochemistry, but also holds significant potential for synthesis of neuro detoxifying drugs to humanity security. [ABSTRACT FROM AUTHOR]

Restrained by uncontrollable dehydrogenation process, the target products of methane direct conversion would suffer from an inevitable overoxidation, which is deemed as one of the most challenging issues in catalysis. Herein, based on the concept of a hydrogen bonding trap, we proposed a novel concept to modulate the methane conversion pathway to hinder the overoxidation of target products. Taking boron nitride as a proof‐of‐concept model, for the first time it is found that the designed N−H bonds can work as a hydrogen bonding trap to attract electrons. Benefitting from this property, the N−H bonds on the BN surface rather than C−H bonds in formaldehyde prefer to cleave, greatly suppressing the continuous dehydrogenation process. More importantly, formaldehyde will combine with the released protons, which leads to a proton rebound process to regenerate methanol. As a result, BN shows a high methane conversion rate (8.5 %) and nearly 100 % product selectivity to oxygenates under atmospheric pressure. [ABSTRACT FROM AUTHOR]

Two‐dimensional conductive metal‐organic frameworks (2D‐c‐MOFs) have attracted extensive attention owing to their unique structures and physical‐chemical properties. However, the planarly extended structure of 2D‐c‐MOFs usually limited the accessibility of the active sites. Herein, we designed a triptycene‐based 2D vertically conductive MOF (2D‐vc‐MOF) by coordinating 2,3,6,7,14,15‐hexahydroxyltriptycene (HHTC) with Cu2+. The vertically extended 2D‐vc‐MOF(Cu) possesses a weak interlayer interaction, which leads to a facile exfoliation to the nanosheet. Compared with the classical 2D‐c‐MOFs with planarly extended 2D structures, 2D‐vc‐MOF(Cu) exhibits a 100 % increased catalytic activity in terms of turnover number and a two‐fold increased selectivity. Density functional theory (DFT) calculations further revealed that higher activity originated from the lower energy barriers of the vertically extended 2D structures during the CO2 reduction reaction process. [ABSTRACT FROM AUTHOR]

Efficient conversion of microplastics into fuels provides a promising strategy to alleviate environmental pollution and the energy crisis. However, the conventional processes are challenged by low product selectivity and potential secondary pollution. Herein, a biotic‐abiotic photocatalytic system is designed by assembling Methanosarcina barkeri (M. b) and carbon dot‐functionalized polymeric carbon nitrides (CDPCN), by which biodegradable microplastics—poly(lactic acid) after heat pretreatment can be converted into CH4 for five successive 24‐day cycles with nearly 100 % CH4 selectivity by the assistance of additional CO2. Mechanistic analyses showed that both photooxidation and photoreduction methanogenesis worked simultaneously via the fully utilizing photogenerated holes and electrons without chemical sacrificial quenchers. Further research validated the real‐world applicability of M. b‐CDPCN for non‐biodegradable microplastic‐to‐CH4 conversion, offering a new avenue for engineering the plastic reuse. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) conversion of methane (CH4) has been extensively explored for the production of value‐added chemicals, yet remains a great challenge in high selectivity toward C2+ products. Herein, we report the optimization of the reactivity of hydroxyl radicals (.OH) on WO3 via facet tuning to achieve efficient ethylene glycol production from PEC CH4 conversion. A combination of materials simulation and radicals trapping test provides insight into the reactivity of.OH on different facets of WO3, showing the highest reactivity of surface‐bound.OH on {010} facets. As such, the WO3 with the highest {010} facet ratio exhibits a superior PEC CH4 conversion efficiency, reaching an ethylene glycol production rate of 0.47 μmol cm−2 h−1. Based on in situ characterization, the methanol, which could be attacked by reactive.OH to form hydroxymethyl radicals, is confirmed to be the main intermediate for the production of ethylene glycol. Our finding is expected to provide new insight for the design of active and selective catalysts toward PEC CH4 conversion. [ABSTRACT FROM AUTHOR]

Fluorine incorporation into organic molecules is expected to lower the pKa of neighboring functionality via its strong electron‐withdrawing effect, and this strategy has been widely exploited in diverse disciplines. Herein, we report a striking anomalous α‐fluorine substitution effect on the α‐Csp3‐H acidity. We have experimentally measured the pKa values of a series of popular nucleophilic monofluoromethylating reagents α‐fluoro(phenylsulfonyl)methane derivatives as well as their C‐H analogues by Bordwell's overlapping indicator method in dimethyl sulfoxide solution. Contrary to expectations, we found that α‐fluorine substituent does not generally enhance but rather weaken the α‐Csp3‐H acidity of most (phenylsulfonyl)methane derivatives. DFT computations reproduce and provide insight into the anomalous α‐fluorine effect. A correlation was identified between the C‐H pKa of (phenylsulfonyl)methane derivatives and Mayr's nucleophilicity parameter (N) of the corresponding carbanions. [ABSTRACT FROM AUTHOR]

H2O2 as a well‐known efficient oxidant is widely used in the chemical industry mainly because of its homolytic cleavage into.OH (stronger oxidant), but this reaction always competes with O2 generation resulting in H2O2 waste. Here, we fabricate heterogeneous Fenton‐type Fe‐based catalysts containing Fe‐Nx sites and Fe/Fe3C nanoparticles as a model to study this competition. Fe‐Nx in the low spin state provides the active site for.OH generation. Fe/Fe3C, in particular Fe3C, promotes Fe‐Nx sites for the homolytic cleavages of H2O2 into.OH, but Fe/Fe3C nanoparticles (Fe0 as the main component) with more electrons are prone to the undesired O2 generation. With a catalyst benefiting from finely tuned active sites, 18 % conversion rate for the selective oxidation of methane was achieved with about 96 % selectivity for liquid oxygenates (formic acid selectivity over 90 %). Importantly, O2 generation was suppressed 68 %. This work provides guidance for the efficient utilization of H2O2 in the chemical industry. [ABSTRACT FROM AUTHOR]

Starting from readily available 7‐substituted 1‐indanones, products with a tetracyclo[5.3.1.01,704,11]undec‐2‐ene skeleton were obtained upon irradiation at λ=350 nm (eight examples, 49–67 % yield). The assembly of the structurally complex carbon framework proceeds in a three‐photon process comprising an ortho photocycloaddition, a disrotatory [4π] photocyclization, and a di‐π‐methane rearrangement. The flat aromatic core of the starting material is converted into a functionalized polycyclic hydrocarbon with exit vectors in three dimensions. Ring opening reactions at the central cyclopropane ring were explored, which enable the preparation of tricyclo[5.3.1.04,11]undec‐2‐enes and of tricyclo[6.2.1.01,5]undecanes. [ABSTRACT FROM AUTHOR]

As a major greenhouse gas, methane, which is directly vented from the coal‐mine to the atmosphere, has not yet drawn sufficient attention. To address this problem, we report a methane nano‐trap that features oppositely adjacent open metal sites and dense alkyl groups in a metal–organic framework (MOF). The alkyl MOF‐based methane nano‐trap exhibits a record‐high methane uptake and CH4/N2 selectivity at 298 K and 1 bar. The methane molecules trapped within the alkyl MOF were crystalographically identified by single‐crystal X‐ray diffraction experiments, which in combination with molecular simulation studies unveiled the methane adsorption mechanism within the MOF‐based nano‐trap. The IAST calculations and the breakthrough experiments revealed that the alkyl MOF‐based methane nano‐trap is a new benchmark for CH4/N2 separation, thereby providing a new perspective for capturing methane from coal‐mine methane to recover fuel and reduce greenhouse gas emissions. [ABSTRACT FROM AUTHOR]