Reactive Intermediates Research Articles

Operando electron spin probes for the study of battery processes

Operando electron spin probes, namely magnetometry and electron paramagnetic resonance (EPR), provide real-time insights into the electrochemical processes occurring in battery materials and devices. In this work, we describe the design criteria and outline the development of operando magnetometry and EPR electrochemical cells. Notably, we show that a clamping mechanism, or springs, are needed to achieve sufficient compression of the battery stack and an electrochemical performance on par with that of a standard Swagelok-type cell. The tandem use of operando EPR and magnetometry allows us to identify five distinct and reversible redox processes taking place on charge and discharge of the intercalation-type LiNi0.5Mn0.5O2 Li-ion cathode. While redox processes in conversion-type electrodes are notoriously difficult to investigate using standard characterization methods (e.g. X-ray based) and/or post mortem analysis, due to the formation of poorly crystalline and metastable reaction intermediates and products during cycling, we show that operando magnetometry provides unique insight into the kinetics and reversibility of Fe nanoparticle formation in the Na3FeF6 electrode for Na-based batteries. Step increases in the cell magnetization upon extended cycling indicate the build-up of Fe nanoparticles in the system, hinting at only partially reversible charge–discharge processes. The broad applicability of the tools developed herein to a range of electrode chemistries and structures, from intercalation to conversion electrodes, and from crystalline to amorphous systems, makes them particularly promising for the development of electrochemical energy storage technologies and beyond.

Arrayed metal phosphide heterostructure by Fe doping for robust overall water splitting

Transition metal phosphides (TMPs) show promise in water electrolysis due to their electronic structures, which activate hydrogen/oxygen reaction intermediates. However, TMPs face limitations in catalytic efficiency due to insufficient active sites, poor conductivity, and multiple intermediate steps in water electrolysis. Here, we synthesize a highly efficient bifunctional self-supported electrocatalyst, which consists of an N-doped carbon shell anchored on Fe-doped CoP/Co2P arrays on nickel foam (NC@Fe-CoxP/NF) using hydrothermal and phosphorization techniques. Experimental and theoretical results indicate that the modified morphology, with increased active site density and a tunable electronic structure induced by Fe doping in the CoP/Co2P heterostructure, leads to superior water electrolysis performance. The resulting NC@Fe0.1-CoP/Co2P/NF catalyst exhibits overpotentials of 122 mV for the hydrogen evolution reaction (HER) and 270 mV for the oxygen evolution reaction (OER) at 100 mA cm−2. Furthermore, using NC@Fe0.1-CoP/Co2P/NF as both the cathode and anode in an alkaline electrolyzer enables the cell system to achieve 100 mA cm−2 at a voltage of 1.70 V, while maintaining long-term catalytic durability. This work may pave the way for designing self-supported, highly efficient electrocatalysts for practical water electrolysis applications.

A Facile Preparation of Tetrasubstituted Arylalkenes Catalyzed by p‐Toluenesulfonic Acid Monohydrate (p‐TsOH⋅H2O): Application in the Synthesis of the Intermediate of Tamoxifen

AbstractAn efficient synthesis of tetrasubstituted arylalkenes was readily achieved by the reaction of α‐(tert‐butyl)benzylic alcohols using p‐toluenensulfonic acid monohydrate as a Brønsted acid. A broad range of substrates was applicable for the reaction in good yield with high regioselectivity. The key intermediate in the synthesis of tamoxifen was produced using the present method as an example, and a plausible reaction mechanism was proposed by examining the reaction intermediates.

Bacteriophage-like Nanobiocatalysts with Spiky Topography and Dual-Atom Sites for Treating Drug-Resistant Bacteria.

Overuse of antibiotics leads to the proliferation of drug-resistant bacterial strains, worsening global morbidity, and mortality rates. Bioinspired nanomaterials present a promising avenue for developing nonantibiotic strategies against drug-resistant bacteria. Here, we engineer a bacteriophage-inspired artificial nanobiocatalyst via nonstoichiometric W18O49 that features a spiky topography and synergistic dual-atom sites for combating drug-resistant bacterial infection. Benefiting from the strong interaction within the synergistic Fe-O-Mo sites, the synthesized spiky artificial nanobiocatalyst exhibits superior reactive oxygen species (ROS)-catalytic activity, attributed to the regulated adsorption affinity between the reaction intermediates and catalytic sites. The experimental and theoretical investigations demonstrate that the bioinspired biocatalyst can effectively capture and kill bacteria through its spiky morphology and potent ROS-catalytic activity, which can enable a significant reduction in bacterial viability through downregulating genes associated with biosynthesis, cellular maintenance, and respiration. In vivo experiments demonstrate that the spiky artificial biocatalyst accelerates the reconstruction of drug-resistant bacteria-infected skin wounds in rabbits, exhibiting efficacy comparable to that of vancomycin. It is expected that this bioinspired study on spiky artificial nanobiocatalysts offers a straightforward path to facilitate the development of both bionic and nonantibiotic disinfection strategies.

How Can the Diterpene Synthase CotB2V80L Alter the Product Profile?

AbstractStructural diversity of diterpenes is mediated by the enigmatic family of diterpene synthases. The overall enzymatic contribution hereby lies in a carefully concerted chemistry of highly reactive carbocation intermediates mainly guided by aromatic and polar amino acid side chains and the pyrophosphate cofactor. To date several studies aimed to shed light on the mechanism underlining terpene synthases chemistry. Specifically, the diterpene synthase CotB2 serves as model enzyme for detailed mutagenesis studies. Here we investigate the catalytic mechanism of CotB2 variant V80L in a holistic, biochemical, structural, and computational biology approach. We were able to identify an altered product profile compared to CotB2WT for the substrates geranylgeranyl diphosphate and farnesyl diphosphate. Moreover, we solved the crystal structure, and shed further light on terpene synthase chemistry by modelling of the substrate and intermediate binding.

Schrittweiser Abbau von weißem Phosphor: Experimentelle und computergestützte Studien zum Mechanismus der P4‐Hydrostannylierung

AbstractDie Hydrostannylierung der wichtigen Basischemikalie weißer Phosphor (P4) ermöglicht in einer Eintopf‐Reaktion und sogar auf katalytischem Weg die Synthese nützlicher P1‐Produkte. Bisher ist das mechanistische Verständnis dieser Methode jedoch mangelhaft, was die Nutzung für weitere Reaktionen einschränkt. Mit Hilfe von sterisch anspruchsvollen Zinnhydriden, zeitaufgelösten 31P‐NMR‐Experimenten und DFT‐Rechnungen geben wir nun fundierte Einblicke in den Mechanismus der P4‐Hydrostannylierung und beschreiben die Identifikation und Isolierung bisher unbekannter Reaktionsintermediate. Die Ergebnisse erlauben Rückschlüsse zur Kinetik der Reaktion und liefern praktische Hinweise für zukünftige Arbeiten auf dem Gebiet der P4‐Aktivierung.

Arylcyanation of Styrenes by Photoactive Electron Donor-Acceptor Complexes/Copper Catalysis.

A novel electron donor-acceptor (EDA) complex/copper catalysis model has been proposed for the construction of 2,3-diarylpropionitriles under visible light conditions. The developed protocol proceeds via intermolecular charge transfer between the photoactive EDA complex of dibutamine (DBA), aryl thianthrenium salts, and trimethylsilyl cyanide (TMSCN), followed by a copper catalytic cycle. UV-vis absorption measurements confirm the participation of EDA complexes as reactive intermediates. This three-component process proceeds smoothly in the presence of pharmaceutically relevant core structures and sensitive functional groups, which offers the possibility of the precise editing of drug molecules with important scaffolds.

Synergy of pore size and silanols in an –SVR-type zeolite for efficient dynamic benzene/cyclohexane separation

The efficient purification of cyclohexane is critical, serving as an essential feedstock to produce resins, nylon fibers and pharmaceutical intermediates. However, efficient purification remains a challenging task due to the similarity of cyclohexane and benzene molecules in terms of size and boiling point. In this work, we reported on the synergy of pore size and silanols inside an -SVR-type zeolite for the efficient production of ultrapure cyclohexane (benzene <1 ppm) from benzene/cyclohexane mixture. Under ambient conditions, the SSZ-74 zeolite demonstrated the highest mass-based productivity of 14.5 L/kg for ultrapure cyclohexane among several common zeolites with a considerable dynamic selectivity of ~9.5. The separation ability was evaluated through density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. The unique ordered silanols inside the zeolite frameworks demonstrated strong but reversible interactions with benzene through SiOH…π interactions, as revealed by in situ Fourier Transform infrared (FTIR) spectra.

Electronic Structure Regulated Carbon-Based Single-Atom Catalysts for Highly Efficient and Stable Electrocatalysis.

Single-atom-catalysts (SACs) with atomically dispersed sites on carbon substrates have attained great advancements in electrocatalysis regarding maximum atomic utilization, unique chemical properties, and high catalytic performance. Precisely regulating the electronic structure of single-atom sites offers a rational strategy to optimize reaction processes associated with the activation of reactive intermediates with enhanced electrocatalytic activities of SACs. Although several approaches are proposed in terms of charge transfer, band structure, orbital occupancy, and the spin state, the principles for how electronic structure controls the intrinsic electrocatalytic activity of SACs have not been sufficiently investigated. Herein, strategies for regulating the electronic structure of carbon-based SACs are first summarized, including nonmetal heteroatom doping, coordination number regulating, defect engineering, strain designing, and dual-metal-sites scheming. Second, the impacts of electronic structure on the activation behaviors of reactive intermediates and the electrocatalytic activities of water splitting, oxygen reduction reaction, and CO2/N2 electroreduction reactions are thoroughly discussed. The electronic structure-performance relationships are meticulously understood by combining key characterization techniques with density functional theory (DFT)calculations. Finally, a conclusion of this paper and insights into the challenges and future prospects in this field are proposed. This review highlights the understanding of electronic structure-correlated electrocatalytic activity for SACs and guides their progress in electrochemical applications.

Mechanically Differentiated Lithium Versus Sodium Ion Storage in an Alloying‐Type Bismuth Anode

AbstractSodium‐ion battery (SIB) research benefits from lithium‐ion battery (LIB) studies due to Li and Na thermodynamic similarities. However, underneath these thermodynamic considerations lie kinetics factors leading to distinct Na+ versus Li+ storage mechanisms even within the same electrode materials, which is ascribed to either ionic size variations or diffusion path differences. Herein, the library of such non‐negligible factors is extended by targeting an alloying‐type bismuth anode well known for its high volumetric capacity for both Li+ and Na+ storage, showing that the mechanical property of key reaction intermediates also plays a role in differentiating its Na+ versus Li+ storage mechanisms. Applying spatially and temporally resolved in situ transmission electron microscopy to Li+ and Na+ storage within bismuth, it not only demonstrates the thermodynamic similarity in a step‐wise phase transition but also discloses its kinetic distinctions in morphological and structural integrities determined by Young's modulus of involving reaction intermediates and spatial configuration, which well accounts for the surprisingly observed superior Na+ storage performance of Bi anode compared to the inferior Li+ storage. Findings here highlight the role of reaction intermediates’ mechanical properties in regulating the overall cycling durability of electrode materials, and guide future material engineering toward performance enhancement, particularly for SIBs.

Atomic Defects Engineering Boosts Urea Synthesis toward Carbon Dioxide and Nitrate Coelectroreduction.

The atomic defect engineering could feasibly decorate the chemical behaviors of reaction intermediates to regulate catalytic performance. Herein, we created oxygen vacancies on the surface of In(OH)3 nanobelts for efficient urea electrosynthesis. When the oxygen vacancies were constructed on the surface of the In(OH)3 nanobelts, the faradaic efficiency for urea reached 80.1%, which is 2.9 times higher than that (20.7%) of the pristine In(OH)3 nanobelts. At -0.8 V versus reversible hydrogen electrode, In(OH)3 nanobelts with abundant oxygen vacancies exhibited partial current density for urea of -18.8 mA cm-2. Such a value represents the highest activity for urea electrosynthesis among recent reports. Density functional theory calculations suggested that the unsaturated In sites adjacent to oxygen defects helped to optimize the adsorbed configurations of key intermediates, promoting both the C-N coupling and the activation of the adsorbed CO2NH2 intermediate. In-situ spectroscopy measurements further validated the promotional effect of the oxygen vacancies on urea electrosynthesis.

Pressure-induced generation of heterogeneous electrocatalytic metal hydride surfaces for sustainable hydrogen transfer

Metal hydrides are crucial intermediates in numerous catalytic reactions. Intensive efforts have been dedicated to constructing molecular metal hydrides, where toxic precursors and delicate mediators are usually involved. Herein, we demonstrate a facile pressure-induced methodology to generate a cost-effective heterogeneous electrocatalytic metal hydride surface for sustainable hydrogen transfer. Taking carbon dioxide (CO2) electroreduction as a model system and zinc (Zn), a well-known carbon monoxide (CO)-selective catalyst, as a model catalyst, we showcase a homogeneous-type hydrogen atom transfer process induced by heterogeneous hydride surfaces, enabling direct hydrogenation pathways traditionally considered “prohibited”. Specifically, the maximal Faradaic efficiency for formate is enhanced by ~fivefold to 83% under ambient conditions. Experimental and theoretical analyses reveal that unlike the distal hydrogenation route for CO2 to CO over pristine Zn, the Zn hydride surface enables direct hydrogenation at the carbon site of CO2 to form formate. This work provides a promising material platform for sustainable synthesis.

Atomically dispersed nickel-bismuth dual-atom sites for high rate electrochemical CO2 reduction

We report a diatomic-site catalyst configuration constituted by Ni-N3 and Bi-N4 embedded in ultrathin nitrogenated carbon nanosheets (Ni/Bi-N-C) which showed dramatically improved activity and selectivity for the conversion of CO2 to CO. Specifically, the catalyst exhibited high CO Faradaic efficiency (FECO) of above 90 % over a wide potential window from −0.76 to −2.22 versus reversible hydrogen electrode with the maximum CO partial current density up to 312 mA cm−2 in a flow cell, and coupled with robust durability. Ni/Bi-N-C-based membrane electrode assembly (MEA) device presented ultrahigh FECO of 95.7 % at 750 mA and over 100 h of continuous operation without decay under constant current density of 100 mA cm−2. Mechanistic studies and density functional theory calculations reveal that regulating the CO2RR catalytic performance via nearby Ni and Bi active sites can potentially break the activity benchmark of the single metal counterparts because the neighboring Ni and Bi active sites work in synergy to decrease the reaction barrier for the formation of *COOH and desorption of *CO. This work presents an efficient combination of two metal atomic sites which was designed by optimizing the interaction between the atomic sites and key reaction intermediates, resulting in the high-rate electrocatalytic CO2 reduction.

Mechanism of Iron-Catalyzed Oxidative α-Amination of Ketones with Sulfonamides.

We report the mechanism of the iron-catalyzed oxidative α-amination of ketones with sulfonamides. Using linear free energy relationships, competition experiments, and identification of reaction intermediates, we have found that the mechanism of this reaction proceeds through rate-limiting electron transfer to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) from an iron enolate in the process of forming an α-DDQ adduct. The adduct then serves as the electrophile for substitution with sulfonamide nucleophiles, accelerated by iron and additional DDQ. This mechanistic study rules out formation of an α-carbocation intermediate and purely radical mechanistic hypotheses.

Vanadium-doped FeO/NiS nanosheet arrays: Synergistic heterometal doping and heterostructure design for enhanced oxygen evolution catalysis

The quest for high-performance OER electrocatalysts has been a focal point in the field of energy conversion and storage. Despite the promise shown by nickel sulfide-based materials, the enhancement of their catalytic activity through singular strategies has been found to be inadequate for achieving the desired comprehensive performance improvements. In this context, we introduce a novel V-doped FeO/NiS nanosheet array (V-FeO/NiS/NF) synthesized through a synergistic approach involving heteroatom doping and heterostructure engineering. This advanced material exhibits structural integrity, a three-dimensional nanosheet morphology, and superior electrical conductivity, which collectively contribute to its exceptional electrochemical performance. The V-FeO/NiS/NF electrode can reach a current density of 10 mA cm−2 with an impressively low overpotential of 213 mV and sustains its activity for an extended period of 196 hours, surpassing the stability and efficiency of many electrodes. Theoretical insights reveal that vanadium doping significantly lowers the adsorption free energy of key reaction intermediates, thereby facilitating the OER process. This study not only presents a robust and efficient OER electrocatalyst but also paves the way for the design of advanced, cost-effective nickel-based sulfide catalysts through strategic heteroatom incorporation and structural optimization.

Mechanism Insights into Allylic Hydroxylation versus Epoxidation of Propene Catalyzed by Model Catalyst Iron Phthalocyanine in the Presence of Hydrogen Peroxide.

High-valent metal-oxo species are key reactive intermediates in many biological and biological oxidation reactions. Herein, allylic hydroxylation (C-H) versus epoxidation (C═C) reactions of propene with a model catalyst iron phthalocyanine (FePc) in the presence of hydrogen peroxide were investigated contrastively, aiming to probe the active intermediates, structure-activity relationship, and reaction pathways. Our results showed that H2O2 as an oxygen-donor reagent can be easily decomposed on FePc to produce key active intermediates O═FePc and O═FePc═O with the energy barriers of 19.57 and 23.89 kcal/mol, respectively. In the selective oxidation of propene, O═FePc has a small preference for C═C epoxidation over C-H hydroxylation while O═FePc═O has a small preference for C-H hydroxylation. Since the electron-withdrawing O axial ligand in O═FePc═O further increases the radical character (Fe-O·) and Fe-O bond length of the iron-oxo moiety, O═FePc═O has better catalytic performance in both C═C epoxidation and C-H hydroxylation than O═FePc. Furthermore, in the whole reaction processes, the dual-hydrogen bonds between the two terminal H atoms of the alkene and allylic groups of propene and oxygen atom of the iron-oxo moiety would lead to the reaction toward C═C epoxidation while the single-hydrogen bond between the terminal H atom of the allylic group and the oxygen atom of the iron-oxo moiety would lead to the reaction toward C-H hydroxylation, implying that the weakly interacting hydrogen bonds affecting oxidation pathways also play a very important role in the regioselectivity of C═C epoxidation and C-H hydroxylation.

C60 Fullerene-Induced Reduction of Metal Ions: Synthesis of C60-Metal Cluster Heterostructures with High Electrocatalytic Hydrogen-Evolution Performance.

Metal clusters, due to their small dimensions, contain a high proportion of surface atoms, thus possessing a significantly improved catalytic activity compared with their bulk counterparts and nanoparticles. Defective and modified carbon supports are effective in stabilizing metal clusters, however, the synthesis of isolated metal clusters still requires multiple steps and harsh conditions. Herein, we develop a C60 fullerene-driven spontaneous metal deposition process, where C60 serves as both a reductant and an anchor, to achieve uniform metal (Rh, Ir, Pt, Pd, Au and Ru) clusters without the need for any defects or functional groups on C60. Density functional theory calculations reveal that C60 possesses multiple strong metal adsorption sites, which favors stable and uniform deposition of metal atoms. In addition, owing to the electron-withdrawing properties of C60, the electronic structures of metal clusters are effectively regulated, not only optimizing the adsorption behavior of reaction intermediates but also accelerating the kinetics of hydrogen evolution reaction. The synthesized Ru/C60-300 exhibits remarkable performance for hydrogen evolution in an alkaline condition. This study demonstrates a facile and efficient method for synthesizing effective fullerene-supported metal cluster catalysts without any pretreatment and additional reducing agent.

Study of peak Laminar Burning Velocity of several syngas compositions at different temperatures

In the context of the current energy transition, the use of biomass-derived syngas (BDS) is often recognized as a fundamental path towards decreasing fossil fuel dependency and greenhouse gas emissions. However, hydrogen-containing BDS are prone to flame instability problems. More efforts are being carried out aiming at efficiently adopting BDS in industrial combustors with CH4 co-firing or inert gas dilutions by exploring accurate knowledge of burning velocity. To do so, a deeper knowledge of the syngas combustion behaviour is strictly necessary. The objective of this study fits in this framework: in particular, a computational study has been carried out to evaluate kinetic models and present fresh insights on the effects of varying syngas mixtures such as CO/H2, CO/H2/CO2 and CO/H2/CH4 on Laminar Burning Velocity (LBV) and peak LBV location (ΦLBV=max). In-detail chemical kinetic simulations of equimolar (CO: H2 = 1:1) forestry waste syngas were systematically carried out taking advantage of the open-source CANTERA solver. Three detailed kinetic models i.e., newly released FFCM-2, USC mech II, and modified GRI mech III were implemented to report accurate flame parameters at 1 bar and different temperature levels (from 300 K up to 450 K). On comparing the results with experiments, FFCM-2 proved to be a good kinetic model for the considered syngas mixtures CO/H2, CO/H2/CO2 and especially for CO/H2/CH4 for mixtures containing a limited share of 30 % methane at normal and moderately elevated temperature at 0.4 ≤ Φ ≤ 2.1. The USC mech II performed very well for CO/H2, and CO/H2/CO2, while the modified GRI mech III model also gave agreeable predictions for CO/H2/CH4 mixture having rich methane content. Additionally, when varying syngas composition analysis was conducted at different temperatures, the progressive CO2 dilution and CH4 addition of up to 30 % reduced the peak LBV and moved the peak LBV locations (ΦLBV=max) towards lean ER conditions with 9 % and 40 % reductions, respectively; however, only the latter effect was enhanced at the elevated initial temperature. Furthermore, sensitivity analysis of respective syngas mixtures is reported at normal and elevated temperatures to explore the most sensitive intermediate reactions relative to LBV. The shift of peak LBV locations and their enhancement at elevated temperatures also open the research path to study the underlying impacts on the flame modes/regimes and structure, especially CO emissions pathways in syngas with 30 % of CH4 and CO2 additions.

Nanostructured MnMoO4 as a trifunctional electrocatalyst for overall water splitting and CO2 reduction

Electrochemical water splitting and CO2 reduction are important processes to produce hydrogen and low–carbon fuels as renewable energy sources. Here, nanostructured MnMoO4, prepared by the reflux precipitation method, was investigated as a trifunctional electrocatalyst for overall water splitting and CO2 reduction reactions. Using a combination of diffuse reflectance spectroscopy and electrochemical impedance spectroscopy results, a direct band gap of 3.05 eV was obtained experimentally for the prepared MnMoO4. An overpotential of 0.36 V at a current density of 5 mA cm−2 and a Tafel slope of 58 mV dec−1 were obtained for the oxygen evolution reaction. At a current density of 3 mA cm−2, overpotentials of 0.39 V and 0.58 V were achieved in the absence and presence of CO2 bubbling into a 0.1 M KOH solution, respectively, emphasizing the poisoning effect of CO2 reduction intermediates for the hydrogen evolution reaction. Based on the obtained results, MnMoO4 could be a promising electrocatalyst for water splitting and CO2 reduction reactions.

Recent Advances in Electrochemical Carboxylation with CO2.

ConspectusCarbon dioxide (CO2) is recognized as a greenhouse gas and a common waste product. Simultaneously, it serves as an advantageous and commercially available C1 building block to generate valuable chemicals. Particularly, carboxylation with CO2 is considered a significant method for the direct and sustainable production of important carboxylic acids. However, the utilization of CO2 is challenging owing to its thermodynamic stability and kinetic inertness. Recently, organic electrosynthesis has emerged as a promising approach that utilizes electrons or holes as environmentally friendly redox reagents to produce reactive intermediates in a controlled and selective manner. This technique holds great potential for the CO2 utilization.Since 2015, our group has been dedicated to exploring the utilization of CO2 in organic synthesis with a particular focus on electrochemical carboxylation. Despite the significant advancements made in this area, there are still many challenges, including the activation of inert substrates, regulation of selectivity, diversity in electrolysis modes, and activation strategies. Over the past 7 years, our team, with many great experts, has presented findings on electrochemical carboxylation with CO2 under mild conditions. In this context, we primarily highlight our contributions to selective electrocarboxylations, encompassing new reaction systems, selectivity control methods, and activation approaches.We commenced our research by establishing a Ni-catalyzed electrochemical carboxylation of unactivated aryl halides and alkyl bromides in conjunction with a useful paired anodic reaction. This approach eliminates the need for sacrificial anodes, rendering the carboxylation process sustainable. To further utilize the widely existing yet cost-effective alkyl chlorides, we have developed a deep electroreductive system to achieve carboxylation of unactivated alkyl chlorides and poly(vinyl chloride), allowing the direct modification and upgrading of waste polymers.Through precise adjustment of the electroreductive conditions, we successfully demonstrated the dicarboxylation of both strained carbocycles and acyclic polyarylethanes with CO2 via C-C bond cleavage. Furthermore, we have realized the dicarboxylative cyclization of unactivated skipped dienes to produce the valuable ring-tethered adipic acids through single-electron reduction of CO2 to the CO2 radical anion (CO2•-). In terms of the asymmetric carboxylation, Guo's and our groups have recently achieved the nickel-catalyzed enantioselective electroreductive carboxylation reaction using racemic propargylic carbonates and CO2, paving the way for the synthesis of enantioenriched propargylic carboxylic acids.In addition to the aforementioned advancements, Lin's and our groups have also developed new electrolysis modes to achieve regiodivergent C-H carboxylation of N-heteroarenes dictated by electrochemical reactors. The choice of reactors plays a crucial role in determining whether the hydrogen atom transfer (HAT) reagents are formed anodically, consequently influencing the carboxylation pathways of N-heteroarene radical anions in the distinct electrolyzed environments.