Transfer Pathways Research Articles

Convenient synthesis of hollow tubular In2O3/PDA S-scheme inorganic/organic heterojunction photocatalyst for H2O2 production and its mechanism

The development of heterojunction photocatalysts for hydrogen peroxide (H2O2) generation is both environmentally sustainable and cost-effective but presents considerable challenges. In this study, we synthesized hollow tubular indium oxide (In2O3) by calcining In-MIL-68 and subsequently composited it with polydopamine (PDA) via in-situ self-polymerization. This process resulted in the formation of an In2O3/PDA step-scheme (S-scheme) heterojunction. The optimized sample demonstrated H2O2 production rates approximately 2.1 and 4.5 times higher than the pure In2O3 and PDA, respectively. The enhanced photocatalytic performance of the In2O3/PDA composite is the result of several synergistic factors: increased light absorption due to the hollow structure, a larger specific surface area, and high separation efficiency of photo-generated electron-hole pairs facilitated by the S-scheme heterojunction. In-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) confirmed the charge transfer pathway follows the S-scheme mechanism. This work not only highlights a practical method for constructing inorganic/organic S-scheme heterojunction photocatalysts but also provides a detailed analysis of their underlying mechanisms, paving the way for more efficient and sustainable photocatalytic systems.

Investigating the presence, distribution and risk of pharmaceutically active compounds (PhACs) in wastewater treatment plants, river sediments and fish

The increasing consumption of medicines and the lack of efficient technologies in wastewater treatment plants (WWTPs) can release pharmaceutically active compounds (PhACs) into any given river with the subsequent risk to the environment and human health. To assess the occurrence and transfer pathways of PhACs through the river ecosystem, 22 PhACs and one metabolite were analyzed in WWTPs, river sediments and fish collected alongside the Tagus River basin between 2020 and 2022. All the matrices presented at least two drugs being azithromycin the only one quantified in all of them. Analgesics, anti-inflammatories, antihypertensives, antidepressants and beta-blockers were the main PhACs in influents, with median concentrations up to 19 μg/L. In effluents, antihypertensives and antidepressants were the PhACs with the highest contribution. For acetaminophen, ibuprofen, ketoprofen, naproxen, atorvastatin, azithromycin, clarithromycin, sulfamethoxazole, trimethoprim, and valsartan WWTPs treatments reached removal efficiencies above 75%. Compounds with a high tendency to bind to organic matter were retained in sludge (clotrimazole, 96 ng/g before digester, 100%). However, results showed that applied treatments were not effective in removing PhACs from this matrix. Although the total mass balance revealed a high removal rate of some PhACs, many of them were still present in the effluent and their release into rivers became the main source of PhAC pollution of the aquatic ecosystem. The most hydrophobic ones (irbesartan, 24 ng/g, 61%), positively charged (o-desmethylvenlafaxine, 95 ng/g, 68%) and those with affinity to organic matter (clotrimazole, 21 ng/g, 61%) reached sediment samples. Only clotrimazole (7.8 ng/g) and azithromycin (160 ng/g) were found in fish samples. Risk assessment revealed a high risk for (i) acetaminophen, clarithromycin, erythromycin A, and venlafaxine in phototrophic organisms and (ii) acetaminophen and venlafaxine in fish.

Critical impact of biochar on hydroxyl radical generation during humin oxidation

The production of hydroxyl radicals (·OH) via reduced humin oxygenation is well established. As biochar is widely used in environmental restoration, its coexistence with humin in restored soils may affect ·OH generation due to its electron transfer ability. However, the role of biochar in ·OH generation by humin remains largely unexplored. Herein, we investigated the ·OH generation by humin-biochar at different mass ratios. Our results indicated that biochar could significantly enhance the ·OH production by humin when the mass of humin exceeded that of biochar. Notably, when the mass ratio of humin to biochar was 50, the ·OH produced reached 75.1 μM, which is nearly 1.7 times the amount generated by humin alone (43.1 μM). Both single-electron and two-electron transfer pathways coexisted in ·OH generation by humin-biochar. C = O in humin were necessary conditions for the production of ·OH, while the presence of C = C in biochar promoted the generation of ·OH. Using graphene and carbon nanotubes both rich in C = C groups as the model compounds, humin-graphene and humin-carbon nanotubes produced ·OH at 122 μM and 98.8 μM, respectively, significantly higher than those generated by humin alone (43.1 μM). This result confirmed the promoting effect of aromatic C = C on ·OH generation. By contrast, when the biochar mass was greater than or equal to that of humin, ·OH generation was inhibited due to the significant reduction of C = O. In this case, environmentally persistent free radicals (EPFRs) in biochar were the primary structures responsible for ·OH production. This study provides comprehensive insights for the first time into the influence of biochar on ·OH generation by humin and offers a new potential method for the green and efficient removal of pollutants.

Z-scheme heterojunction photocatalyst of LaFeO3@CoS for tetracycline hydrochloride degradation by persulfate activation using visible light

An efficient and stable LaFeO3@CoS Z-scheme heterojunction photocatalyst was prepared through the hydrothermal method (HT). Photocatalytic activity of the LaFeO3@CoS was assessed by activating persulfate under visible light for the degradation of tetracycline (0.1 g/L). Under the condition of 0.06 g/L of KHSO5 (Peroxymonosulfate, PMS), the degradation efficiency of 88.7 % was achieved in 40 min using the 0.02 g/L of developed photocatalyst. The degradation kinetic constants of LaFeO3@CoS were 2.79 and 2.23 times higher than those of LaFeO3 and CoS, respectively. Furthermore, the catalyst exhibited excellent stability over five consecutive degradation cycles. Possible degradation mechanisms and the electron transfer mechanism of the heterojunction formed by the LaFeO3@CoS were investigated by quenching experiments, nitrogen N₂ purging experiments, electron spin resonance (ESR) measurements and corresponding electrochemical analyses. In the LaFeO3@CoS/Vis/PMS system, the Z-scheme charge transfer pathway not only accelerated charge transport efficiency but also effectively spatially separated electrons and holes, enhancing the photocatalytic performance of the photocatalyst. Additionally, the generation of reactive species such as 1O2, O2•−, and SO4• − significantly contributed to the improved degradation efficiency of the present catalyst during the degradation process.

Role of H2O2 as Oxidant and H2O as Co-Catalyst Over Anatase-TiO2(101) for Conversion of Methane to Methanol.

Computations based on density functional theory are carried out to examine the mechanism of photocatalytic oxidation of methane to methanol with H2O2 as oxidant and water as co-catalyst over anatase TiO2(101) surface. The reaction proceeds with hydrogen abstraction from methane followed by the formation of surface methoxy species, which is reduced to methanol. We compare the reaction energetics for C-H dissociation in the presence and absence of surface defect, but find no discernible impact of O-vacancy on methane oxidation. In comparison, hydroxyl produced as a result of H2O2 or H2O photo-decomposition dramatically reduces the barrier for CH3-H bond cleavage. The reaction proceeds further by the reduction of surface methoxy group and is the rate-limiting step for methanol formation. Additionally, we find that methyl can also react with water to form methanol with a considerably lower barrier, suggesting an active involvement of water for methanol formation. We also study the role of water as a co-catalyst and observe significant reduction in barriers, facilitated by alternate pathway for proton transfer. The reaction pathways presented provide valuable insights into the mechanism of methane oxidation in the presence of H2O2 as oxidant and demonstrate the rate-enhancing role of water for these steps.

Cyclic Sulfoximines as Methyl and Perdeuteromethyl Transfer Agents and Their Applications in Photoredox Catalysis.

Benzo[1,3,2]dithiazole-1,1,3-trioxides are bench-stable and easy-to-use reagents. In photoredox catalysis, they generate methyl and perdeuteromethyl radicals which can add to a variety of radical acceptors, including olefins, acrylamides, quinoxalinones, isocyanides, enol silanes, and N-Ts acrylamide. As byproduct, a salt is formed which can be regenerated to the original methylating agent. Flow chemistry provides an option for reaction scale-up further underscoring the synthetic usefulness of these methylation reagents. Mechanistic investigations suggest a single-electron transfer (SET) pathway induced by photoredox catalysis.

Cyclic Sulfoximines as Methyl and Perdeuteromethyl Transfer Agents and Their Applications in Photoredox Catalysis

AbstractBenzo[1,3,2]dithiazole‐1,1,3‐trioxides are bench‐stable and easy‐to‐use reagents. In photoredox catalysis, they generate methyl and perdeuteromethyl radicals which can add to a variety of radical acceptors, including olefins, acrylamides, quinoxalinones, isocyanides, enol silanes, and N‐Ts acrylamide. As byproduct, a salt is formed which can be regenerated to the original methylating agent. Flow chemistry provides an option for reaction scale‐up further underscoring the synthetic usefulness of these methylation reagents. Mechanistic investigations suggest a single‐electron transfer (SET) pathway induced by photoredox catalysis.

Metabolic engineering of Escherichia coli for the utilization of methylsuccinate, the product of methane activation via fumarate addition

Methylsuccinate is a branched-chain, 5-carbon (C5) dicarboxylate that can be generated from the O2-independent activation of methane via fumarate addition. However, no established metabolic pathway enables growth and product synthesis from methylsuccinate. Here, we report a synthetic pathway that converts methylsuccinate into two precursor metabolites: pyruvate and acetyl-CoA. The pathway was constructed through rational design and validated both in vitro and in vivo using E. coli as the host. Subsequently, growth on methylsuccinate as the sole carbon source was achieved using two parallel strategies: adaptive laboratory evolution and enzyme mining. Through the latter approach, we identified a heterologous electron transfer pathway mediated by previously uncharacterized enzymes and integrated into E. coli enabling the conversion of methylsuccinyl-CoA to mesaconyl-C4-CoA. The engineered strain demonstrated efficient growth on various C5 dicarboxylates including methylsuccinate, mesaconate, and itaconate, with a specific growth rate of 0.11 h−1 on methylsuccinate. This study represents an important step toward achieving synthetic methanotrophy, as the engineered strain can serve as a platform for screening potential methane activation enzymes and ultimately as a production chassis for the bioconversion of methane into various value-added products.

Regulating the Twisted Intramolecular Charge Transfer and Anti-heavy Atom Effect at Supramolecular Level for Favorable Photosensitizing Activity in Water.

Photosensitizing assemblies based on twisted intramolecular charge transfer (TICT) active donor-acceptor-donor (D-A-D) system BrTPA-Qx having bromine atoms at the periphery have been developed. Through strategic incorporation of bromine atoms at the para-position to the nitrogen-carbon bonds of phenyl rings at the periphery, halogen-halogen interactions are induced in BrTPA-Qx nanoassemblies in H2O:DMSO (99:1) solution. Hence, the anti-heavy atom effect is induced, and the limitations of TICT (dark excited state) and heavy atom effect (triplet deactivation via radiative decay) could be overcome. Because of TICT and anti-heavy atom effect, supramolecular BrTPA-Qx nanoassemblies demonstrate high efficiency in promoting activation of aerial oxygen via electron and energy transfer pathways in aqueous media. The significant influence of the stabilized TICT state and anti-heavy-atom effect in controlling the ROS generation was validated through in-depth solvent-dependent photophysical studies and investigations of the structure-activity relationship in several model compounds. The notable photosensitizing activity of BrTPA-Qx nanoassemblies is manifested in their ability to efficiently catalyze the oxidative coupling of benzylamine (via type I and type II mechanisms), Knoevenagel condensation of aromatic aldehydes (type II), and oxidative hydroxylation of arylboronic acids (type I) under mild conditions.

Triphasic Hydroxysilylation of Alkenes by Mechanically Piezoelectric Catalysis.

The 1,2-hydroxysilylation of alkenes is crucial for synthesizing organosilicon compounds which are key intermediates in material science, pharmaceuticals, and organic synthesis. The development of strategies employing hydrogen atom transfer pathways is currently hindered by the existence of various competing reactions. Herein, we reported a novel mechanochemical strategy for the triphasic 1,2-hydroxysilylation of alkenes through a single-electron-transfer pathway. Our approach not only circumvents competitive reactions to enable the first-ever 1,2-hydroxysilylation of unactivated alkenes but also pioneers the research in mechanic force-induced triphasic reactions under ambient conditions. This gentle method offers excellent compatibility with various functional groups, operates under simple and solvent-free conditions, ensures rapid reaction time. Preliminary mechanistic investigations suggest that silylboronate can be transformed to a silicon radical by highly polarized Li2TiO3 particles and oxygen under ball-milling condition.

Plasmon-Enhanced Photoelectrochemistry of Photosystem II on a Hierarchical Tin Oxide Electrode for Ultrasensitive Detection of 17β-Estradiol.

Despite its excellent efficiency in natural photosynthesis, the utilization of photosystem II (PSII)-based artificial photoelectrochemical (PEC) systems for analytical purposes is hindered due to the low enzyme loading density and ineffective electron transfer (ET) processes. Here, we present a straightforward and effective approach to prepare a PSII-based biohybrid photoanode with remarkable photoresponse, enabled by the use of a hierarchically structured inverse-opal tin oxide (IO-SnO2) electrode combined with gold nanoparticles (Au NPs). The porous, carbon-containing IO-SnO2 structure allows for a high density and photoactivity loading of PSII complexes, while also providing strong electrical coupling between the protein film and the electrode. A new electron transfer pathway mediated by Au NPs was identified at the protein-electrode interface, which efficiently shuttles the photogenerated electrons from the enzyme to the IO-SnO2 electrode. Furthermore, the PEC response of the electrode was significantly enhanced by the surface plasmon resonance (SPR) effect of Au NPs. Upon light irradiation, this PSII-based photoanode exhibited an impressively high and stable photocurrent output, which was utilized to fabricate an aptasensor for 17β-Estradiol (E2) detection. Under optimal conditions, a detection limit of 0.33 pM was obtained, along with a broad detection range from 15 pM to 30 nM. The applicability of the aptasensor was assessed by measuring E2 in water and urine samples, demonstrating its feasibility in environmental monitoring and clinical tests.

Non‐Fused Star‐Shape Giant Trimer Electron Acceptors for Organic Solar Cells with Efficiency over 19 %

AbstractOrganic solar cells (OSCs) based on giant molecular acceptors (GMAs) have attracted extensive attention due to their excellent power conversion efficiency (PCE) and operation stability. However, the large conjugated plane of GMAs poses great challenges in regulating the solubility, over‐size aggregation and yield, which in turn further constrains their development in commercial products. Herein, we employ a non‐fused skeleton strategy to develop novel non‐fused star‐shape trimers (3BTT6F and 3BTT6Cl) for improving device performance. Single‐bond linkage can break the rigid planarity to form a 3D architecture, generating multidimensional charge transfer pathways. Importantly, the non‐fused skeleton strategy can not only significantly improve solubility and synthesis yield, but also effectively suppress molecular excessive aggregation. Consequently, due to the optimized film‐forming process and charge dynamics, 3BTT6F‐based binary device obtains a high PCE of 17.52 %, which is significantly higher than the reported fully fused trimers. Excitingly, 3BTT6F‐based ternary device even obtains a top‐level PCE of 19.26 %. Furthermore, the non‐fused star‐shape configuration also endows these acceptors with enhanced intermolecular interaction in the active layer, demonstrating excellent operational stability. Our work emphasizes the potential of non‐fused star‐shape trimers, providing a new pathway for achieving highly efficient and stable OSCs.

Indications for Transfer and Care Pathways of Inuit Transferred to a Tertiary Centre for Childbirth in Québec, Canada: A Chart Review 2015–2019

ObjectivesChildbirth evacuation, the transfer of patients from rural and remote communities to urban centres for pregnancy care or childbirth, can be associated with numerous adverse health outcomes and contributes to widening health disparities between Inuit and non-Indigenous populations in Québec. We examined the indications and outcomes of childbirth evacuations among Inuit from Nunavik, Northern Québec transferred to a southern tertiary care centre. MethodsA 5-year retrospective chart review included 677 pregnancies of 597 Inuit with obstetric indications transferred to a tertiary care centre between 2015 and 2019. ResultsThe most common reasons for transfer were diabetes (70/677, 10.3%), hypertension (69/677, 10.2%), abnormal prenatal screen/soft markers (57/677, 8.4%), and threatened preterm labour (55/677, 8.1%). Of the 534 (78.9%) Inuit who gave birth at the tertiary centre, 84.1% (449/534) were vaginal births. Overall, 27.0% (144/534) had obstetric complications, with postpartum hemorrhage (58/534, 10.9%) and retained placenta (34, 6.37%) being the most common. Of the 549 neonates, 9 were stillbirths (1.6%), and 69 neonates (12.6%) required admission to the neonatal intensive care unit. Approximately 3.4% (18/534) had complications within the postpartum period, with the most common being retained products of conception (4/18, 22.2%) and postpartum preeclampsia (4/18, 22.2%). ConclusionsA relatively young and multiparous population, Inuit from Nunavik have unique health profiles and care needs. Further investment in health care capacity in Nunavik, alongside locally adapted, prevention-focused perinatal health programming, might improve perinatal health profiles and reduce the rates of childbirth evacuation.

Achieving high electrothermal and mechanical performance for Graphene/Poly(hexamethylene terephthalamide) composite films via interfacial engineering with two-dimensional polyarylamide nanosheets

Although graphene-based polymer electrothermal films have received great attention, the graphene aggregation restricts the improvement in electrothermal performance. This study reports graphene (GN)/two-dimensional polyarylamide nanosheets (2DPA) filled poly (hexamethylene terephthalamide) (PA6T) composite film with outstanding electrothermal and mechanical performance. Owing to the addition of 2DPA, the as-prepared 2DPA-GN/PA6T composite film can attain a high heating-up rate of 25.5 °C/s, 1.8 times higher than that of GN/PA6T composite film (14.1 °C/s). Furthermore, the 2DPA-modified composite film showed a remarkable heating temperature rise to ∼230 °C, 80 °C higher than that of GN/PA6T composite film (∼150 °C). Additionally, the film had excellent mechanical performance with tensile strength and modulus of elasticity of 32.5 MPa and 4.6 GPa, which were 24.2 % and 52.3 % higher than that of GN/PA6T composite film, respectively. Such outstanding performance came from strong interfacial adhesion between GN and PA6T, induced by 2DPA nanosheets through hydrogen bonding and π-π interactions, which were confirmed by FTIR and UV–Vis measurements. Besides improving interfacial adhesion, 2DPA can also reduce the surface defect density of the GN through π-π conjugation. Both improved interfacial adhesion and reduced defects of GN contributed to the formation of electrically conductive and stress transfer pathways, which supported the excellent electrothermal and mechanical properties of 2DPA-GN/PA6T composite films. This study demonstrates an effective way to prepare high-performance graphene composites for electrothermal applications, with expected uses in aerospace, industry, and other technological fields.

Multifunctional Conductive MOFs Enhance the Photocatalytic Hydrogen Evolution Efficiency of S-Type Ni3(HITP)2/TiO2 Heterojunctions.

Despite their high surface area, remarkable porosity, and efficient charge transfer mechanisms, conductive MOFs have found limited utilization within the domain of photocatalysis. In this study, we synthesized a cutting-edge S-type Ni3(HITP)2/TiO2 heterojunction photocatalyst exhibiting outstanding light harvesting and prolonged lifetime of photogenerated electrons through an in situ synthesis approach. Compared with TiO2, the composite materials not only significantly increase the specific surface area by 4.07 times but also expand the visible light absorption edge from 400 to 1100 nm. The hydrogen production rate of Ti/Ni-3 reached 4.927 mmol·g-1·h-1, which is 4.51 times that of TiO2. The S-type interface charge transfer pathway of the Ni3(HITP)2/TiO2 composite material was inferred by band structure, in situ XPS, SPV, and free radical capture, which improves charge separation and extends the carrier lifetime to undergo directional migration driven by an IEF. This is the main reason for the improved photocatalytic performance of Ni3(HITP)2/TiO2 composite materials.

Coupling Conversion of CO2 and High‐Carbon Alkane to CO and Gasoline

AbstractCatalytic conversion of CO2 to valuable products is a promising way to reduce anthropogenic CO2 emission. Herein, a strategy for coupling conversion of CO2 and high‐carbon alkane to CO and gasoline is developed, which is a feasible choice for the combination of CO2 recycling and petroleum refining. The CO2 conversion reaches 2.6% under mild condition (270 °C), and the selectivity of gasoline in the cracking products exceeds 70 wt%. Additionally, the introduction of CO2 improves the selectivity of aromatic hydrocarbons and increases the octane number of gasoline. Mechanism studies indicate that synergistic effect between Brønsted acid centers and Ni sites on the Beta zeolite supported Ni (20 wt%) catalyst (20Ni/β) plays the key role in alkane cracking and CO2 reduction. Notably, 13CO2 isotopic experiments show that the hydrogen produced during the aromatization can be captured by CO2, inhibiting undesired hydrogen transfer pathways and enhanced the yield of aromatics, while CO2 is converted into valuable CO.

Regulation of Exciton Effects in Functionalized Conjugated Polymers by B‐N Lewis Pairs for Visible‐Light Photocatalysis

Strong excitonic effects are common in organic conjugated polymer semiconductors, severely hindering the generation of free charge carriers for conducting photocatalysis. Therefore, exploring new channels to modulate exciton dissociation in polymers is far‐reaching in facilitating photocatalysis. A series of B‐N Lewis pair functionalized conjugated polymers have been developed to minimize exciton effects by modulating charge transfer pathways. Theoretical studies have shown that introducing B‐N Lewis pairs can dramatically increase the distance of charge transfer (D index) and the amount of electron transfer and reduce the Coulomb attraction energy (EC), which contributes to breaking the equilibrium of the coexistence of excitons and charge carriers. Further experimental results show that the singlet excitons are efficiently dissociated into more free‐charge carriers under photoexcitation to participate in surface reactions. The optimized polymer PyPBM shows an exponential increase in photocatalytic hydrogen and hydrogen peroxide production performance by visible light illumination.

Unraveling the molecular determinants of a rare human mitochondrial disorder caused by the P144L mutation of FDX2.

Episodic mitochondrial myopathy with or without optic atrophy and reversible leukoencephalopathy (MEOAL) is a rare, orphan autosomal recessive disorder caused by mutations in ferredoxin-2 (FDX2), which is a [2Fe-2S] cluster-binding protein participating in the formation of iron-sulfur clusters in mitochondria. In this biosynthetic pathway, FDX2 works as electron donor to promote the assembly of both [2Fe-2S] and [4Fe-4S] clusters. A recently identified missense mutation of MEOAL is the homozygous mutation c.431C>T (p.P144L) described in six patients from two unrelated families. This mutation alters a highly conserved proline residue located in a loop of FDX2 that is distant from the [2Fe-2S] cluster. How this Pro to Leu substitution damages iron-sulfur cluster biosynthesis is unknown. In this work, we have first compared the structural, dynamic, cluster binding and redox properties of WT and P144L [2Fe-2S] FDX2 to have clues on how the pathogenic P144L mutation can perturb the FDX2 function. Then, we have investigated the interaction of both WT and P144L [2Fe-2S] FDX2 with its physiological electron donor, ferredoxin reductase FDXR, comparing their electron transfer efficiency and protein-protein recognition patterns. Overall, the data indicate that the pathogenic P144L mutation negatively affects the FDXR-dependent electron transfer pathway from NADPH to FDX2, thereby reducing the capacity of FDX2 in assembling both [2Fe-2S] and [4Fe-4S] clusters. Our study also provided solid molecular evidences on the functional role of the C-terminal tail of FDX2 in the electron transfer between FDX2 and FDXR.

Signatures of coherent vibrational dynamics in ethylene carbonate.

Despite having practical applications in battery technology and serving as a model system for Fermi resonance coupling, ethylene carbonate (EC) receives little direct attention as a vibrational probe in nonlinear vibrational spectroscopy experiments. EC contains a Fermi resonance that is well-characterized in the linear spectrum, and the environmental sensitivity of its Fermi resonance peaks could make it a good molecular probe for two-dimensional infrared spectroscopy (2DIR) experiments. As a model system, we investigate the linear and 2DIR vibrational spectrum of the carbonyl stretching region of ethylene carbonate in tetrahydrofuran. The 2DIR spectrum reveals peak dynamics that evolve coherently. We characterize these dynamics in the context of Redfield theory and find evidence that EC dynamics proceed through coherent pathways, including singular coherence transfer pathways that have not been widely observed in other studies. We find that coherent contributions play a significant role in the observed dynamics of cross-peaks in the 2DIR spectrum, which must be accounted for to extract accurate measurements of early waiting time dynamics.

Two-Dimensional Covalent Organic Frameworks with Carbazole-Embedded Frameworks Facilitate Photocatalytic and Electrocatalytic Processes.

Catalytic technologies are pivotal in enhancing energy efficiency, promoting clean energy production, and reducing energy consumption in the chemical industry. The pursuit of novel catalysts for renewable energy is a long-term goal for researchers. In this work, we synthesized three two-dimensional covalent organic frameworks (COFs) featuring electron-rich carbazole-based architectures and evaluated their catalytic performance in photocatalytic organic reactions and electrocatalytic oxygen reduction reactions (ORRs). Pyrene-functionalized COF, termed as FCTD-TAPy, demonstrated excellent photocatalytic performance for amino oxidation coupling and showed a remarkable preference for substrates with electron-withdrawing groups (up to >99% Conv. and >99% Sel). Furthermore, FCTD-TAPy favored a four-electron transfer pathway during the ORR and exhibited favorable reaction kinetics (51.07 mV/dec) and a high turnover frequency (0.011 s-1). In contrast, the ORR of benzothiadiazole-based FCTD-TABT favored a two-electron transfer pathway, which exhibited a maximum double-layer capacitance of 14.26 mF cm-2, a Tafel slope of 53.01 mV/dec, and a hydrogen peroxide generation rate of 70.3 mmol g-1 h-1. This work underscores the potential of carbazole-based COFs as advanced catalytic materials and offers new insights into the design of metal-free COFs for enhanced catalytic performance.