Carbon Recycling Research Articles

Photorespiratory glycine contributes to photosynthetic induction during low to high light transition

Leaves experience near-constant light fluctuations daily. Past studies have identified many limiting factors of slow photosynthetic induction when leaves transition from low light to high light. However, the contribution of photorespiration in influencing photosynthesis during transient light conditions is largely unknown. This study employs dynamic measurements of gas exchange and metabolic responses to examine the contribution of photorespiration in constraining net rates of carbon assimilation during light induction. This work indicates that photorespiratory glycine accumulation during the early light induction contributes 5–7% to the additional carbon fixed relative to the low light conditions. Mutants with large glycine pools under photorespiratory conditions (5-formyl THF cycloligase and hydroxypyruvate reductase 1) showed a transient spike in net CO2 assimilation during light induction, with glycine buildup accounting for 22–36% of the extra carbon assimilated. Interestingly, levels of many C3 cycle intermediates remained relatively constant in both mutants and wild-type throughout the light induction period where glycine accumulated, indicating that recycling of carbon into the C3 cycle via photorespiration is not needed to maintain C3 cycle activity under transient conditions. Furthermore, our data show that oxygen transient experiments can be used as a proxy to identify the photorespiratory component of light-induced photosynthetic changes.

Driving sustainability and performance: 3D-printing of lightweight functional components using recycled carbon fiber reinforced polyphenylene sulfide composites for automotive industry

Driving sustainability and performance: 3D-printing of lightweight functional components using recycled carbon fiber reinforced polyphenylene sulfide composites for automotive industry

High-efficiency C3 electrosynthesis on a lattice-strain-stabilized nitrogen-doped Cu surface

The synthesis of multi-carbon (C2+) fuels via electrocatalytic reduction of CO, H2O using renewable electricity, represents a significant stride in sustainable energy storage and carbon recycling. The foremost challenge in this field is the production of extended-chain carbon compounds (Cn, n ≥ 3), wherein elevated *CO coverage (θco) and its subsequent multiple-step coupling are both critical. Notwithstanding, there exists a “seesaw” dynamic between intensifying *CO adsorption to augment θco and surmounting the C-C coupling barrier, which have not been simultaneously realized within a singular catalyst yet. Here, we introduce a facilely synthesized lattice-strain-stabilized nitrogen-doped Cu (LSN-Cu) with abundant defect sites and robust nitrogen integration. The low-coordination sites enhance θco and concurrently, the compressive strain substantially fortifies nitrogen dopants on the catalyst surface, promoting C-C coupling activity. The n-propanol formation on the LSN-Cu electrode exhibits a 54% faradaic efficiency and a 29% half-cell energy efficiency. Moreover, within a membrane electrode assembly setup, a stable n-propanol electrosynthesis over 180 h at a total current density of 300 mA cm−2 is obtained.

Identifying the dominant compound events and their impacts on vegetation growth in China

Terrestrial vegetation plays a vital role in global carbon recycling, but it is also affected by compound events (CEs); however, little is known about the impacts of these CEs on vegetation in terms of their occurrence and magnitude. Using meteorological observations and vegetation indices (leaf area index (LAI), gross primary productivity (GPP), and net primary productivity (NPP)) from 1981 to 2020, we explored the occurrence of 13 CEs types and identified the dominant CEs types across different eco-geographical regions of China, and quantified the response of various vegetation types to dominant CEs. We found that CEs of extreme hot-dry, extreme hot-dry-high fire weather, dry-high fire weather, and high fire weather-strong wind were the dominant types of compound events during the growing season in China, and their hazards increased at a rate of >0.1HI/10a during 1981–2020. We further detected that more than 60% of the total vegetation areas showed a strong negative correlation with compound extreme hot-dry-high fire weather-strong wind events, which was relatively higher than compound extreme hot-dry events. The response of vegetation to compound events varied at the national scale, which was related to the vegetation type, dominant compound event type, and local natural conditions. This study highlights the benefits of a multivariate perspective on compound events and reveals the regional differences in the response of vegetation to compound events, which can provide initial guidance to assess the regional compound event risk of vegetation against the background of carbon neutrality by 2060.

Carbon and oxygen recycling strategies in CO2-to-sustainable synthetic fuel production: Recycling route, techno-economics and carbon intensity

Anthropogenic carbon utilization and recycling into fuel using renewably sourced or nuclear energy and water is a potentially valuable strategy for replacing fossil fuels. The high-level elemental balance of the CO2-to-Fuel system involves oxygen rejection, with CO2 and H2O reduction dependent on crucial process steps that determine performance metrics such as energy efficiency, element utilization, economics, and carbon footprint. This study elaborates on carbon and oxygen recycling strategies for producing sustainable synthetic hydrocarbon fuels. It covers electrolysis routes, internal recycling pathways, and additional processes to increase synfuel yield. An element balance was derived for four process schemes with systematic recycling route variations, facilitating a comparison of elemental efficiencies: (1) carbon utilization (80.7–90.6 %), (2) hydrogen efficiency (4.8–30.8 %), and (3) oxygen gas rejection rate (56.8–63.1 %). A process flow diagram was proposed to discuss techno-economics through the existing route via the Fischer-Tropsch process. The energy intensity ranged from 118.5 to 177.4 GJ per tonne of synfuel, and the energy conversion efficiency varied from 0.24 to 0.36. We further evaluated the carbon intensity, considering the primary energy efficiency to show the different energy supply scenarios, including (i) 100 % fossil-based (506–1416 kgCO2eq/GJFuel), (ii) grid power with fossil fuel (246–687 kgCO2eq/GJFuel), (iii) hybridization of renewable sources (biomass and wind power) (42–78 kgCO2eq/GJFuel), and (iv) nuclear energy (7–18 kgCO2eq/GJFuel). This work considers the interplay between oxygen rejection, syngas conversion, and combustion, undertaking a novel analysis to bridge the high-level elemental analysis with detailed metrics calculations.

Insights into effects of conventional and biodegradable microplastics on organic carbon decomposition in different soil aggregates

The impacts of microplastics on soil ecological functions such as carbon recycling and soil structure maintenance have been extensively focused. However, the mechanisms underlying the impacts of microplastics on soil carbon transformation and soil microbial community at soil aggregate scale have not been clarified yet. In this work, the effects and action mechanisms of traditional microplastic polypropylene (PP) and degradable microplastic polylactic acid (PLA) on carbon transformation in three sizes of soil aggregates were investigated. The results showed that both PP and PLA promoted CO2 emission, and the effect depended on the type and content of microplastics, and the size of soil aggregates. Changes in soil carbon stocks were mainly driven by changes in organic carbon associated with macroaggregates. For macroaggregates, PP microplastics decreased soil organic carbon (SOC) as well as dissolved organic carbon (DOC). These changes were reversed in microaggregates and silt and clay. Interestingly, PLA increased the SOC, DOC and CO2 emissions in bulk soil and all three aggregates with a dose-effect response. These changes were associated with soil microbes, functional genes and enzymes associated with the degradation of labile and recalcitrant carbon fractions. Furthermore, PP and PLA reduced bacterial community diversities and shifted bacterial community structures in both the three aggregates and in bulk soil. Alterations of functional genes induced by microplastics were the key driving factors of their impacts on carbon transformation in soil aggregates. This research opened up a new insight into the mechanisms underlying the impacts of microplastics on soil carbon transformation, and helped us make rational assessments of the risks and the disturbances of microplastics on soil carbon cycling.

Performance study of high energy storage supercapacitor from waste corn husk biomass electrode materials

Waste biomass carbon materials are used as green and environmentally friendly electrode materials for supercapacitors (SCs) have great development prospects, therefore, miscellaneous elements-rich and recycled renewable porous carbon materials have important applications value in the field of energy storage device. In this paper, waste corn husk as biomass precursor to prepare corn husk porous carbon (CHPC) using two steps of high-temperature carbonization and KOH activation. The CHPC-2 optimized by KOH shows a specific surface area (SSA) of 1103 m2 g−1 and a total pore volume of 0.83 cm3 g−1, achieving a high specific capacitance of 413.4 F g−1 at 0.5 A g−1. After 10,000 cycles, only 4.17 % of the capacitance was lost. In a two-electrode system with 1 M Na2SO4 as the electrolyte, CHPC-2//CHPC-2 exhibits a specific capacitance of 333 F g−1 at a wide voltage window of 0–1.8 V, and energy density of 37.46 Wh Kg−1 when power density is 450 W kg−1, which possesses the capacitance retention rate of 85.16 % after 5000 cycles. The assembled symmetrical SCs contain capacitance of 308.79 F g−1, and 21.02 Wh kg−1 under a power density of 350 W kg−1 in PVA/KOH gel electrolyte. Consequently, CHPC materials provide a scientific and reasonable research idea for the development of SCs with inexpensive, non-polluting, and high energy density.

Recyclable carbon nitride composite catalyst for degradation of tetracycline under natural light in a novel iron-free photo-Fenton system

Fenton technology has great advantages in treating antibiotic pollution, but the generation and treatment of iron sludge has always restricted the development and application of traditional Fenton technology. In this work, an iron-free photo-Fenton (IF-PF) system with MoS2/TCNCl-S(P) as the core catalyst was established to achieve efficient degradation of antibiotics. We investigated the efficiency and stability of MoS2/TCNCl-S(P) in degrading tetracycline (TC) in IF-PF system. The cyclic mass transfer between photogenerated carrier and H2O2 in the IF-PF system was explained, and the transformation mechanism of H2O2 into strong oxidizing free radicals under the action of photogenerated carrier was revealed, and it was used for the degradation of antibiotics under natural light. The experimental results show that the efficient degradation of TC by IF-PF (MoS2/TCNCl-S(P)) system under natural light is mainly due to the abundant formation of radO2– and radOH. This finding offers a promising research direction for the photocatalytic degradation of organic pollutants in natural light conditions.

Electrochemical CO2 Reduction on Silver – a Perspective through Electrochemical Impedance Spectroscopy

Anthropogenic carbon rise in the earth's atmosphere is the leading cause towards global warming. Electrochemical CO2 reduction (eCO2RR) is one of the most promising sustainable pathways for the utilization and recycling of anthropogenic carbon. The current challenge in eCO2RR is to make the process more energy efficient and to drive the selectivity toward the desired products. eCO2RR normally takes place in parallel with hydrogen evolution reaction (HER). Additionally, dependent on catalyst material and potential different C-products can be obtained. The mechanistic understanding of the interplay between different reactions is still limited, since the involved reactions are characterized by faster kinetics and/or different adsorbed species as well as mass transfer dependences than the other ones. Moreover, we have recently shown that under dynamic conditions eCO2RR product selectivity towards CO can be tuned1. In that study, we developed a simple model and identified key kinetic parameters which govern product selectivity under dynamic conditions. The model included only the electrochemical kinetics of two parallel reactions without consideration of adsorbed species or mass transport limitations. Therefore, some of the experimental observations could not be completely explained. In such complicated cases involving different physicochemical phenomena acting in parallel at different time scales, the use of electrochemical impedance spectroscopy (EIS) to analyse the system could shed light on the understanding of the process.In this contribution, we have developed a mathematical model which couples micro-kinetics with continuum transport. At first, the model was validated under steady-state conditions. The experiments have been performed under different conditions (mass transport and buffer concentrations) on silver rotating disk electrodes and the product distribution (H2 and CO) has been determined with the help of online gas chromatography. This model was then used to calculate EIS. Based on this approach, we present here a detailed interpretation of the EIS spectrum during eCO2RR and the features obtained at different applied electric potentials. Key insights are drawn about the role of charge and mass transport as well as adsorbed intermediates on the observed features.

Equal per capita carbon dividends and the waste objection

ABSTRACT Recycling carbon revenues as Equal Per Capita Carbon Dividends (ECDs) is thought to neutralise the two main objections to carbon pricing, namely that it is regressive and that it hinders the poor from meeting basic needs. This article focuses on the waste objection to carbon pricing plus ECDs. If the rationale for ECDs is to protect the consumption of the worst off, why pay carbon dividends to the rich as well? I examine three different normative arguments in favour of ECDs. First, the argument of common ownership of the atmosphere, which can be based on both libertarianism and isolationist egalitarianism. Second, the argument that the rich are net contributors to ECDs through their carbon taxes. Third, a consequentialist argument focusing on the pragmatic advantages of ECDs, especially in terms of social acceptability and low information costs. I conclude that none of these arguments can provide a normative justification for ECDs.

Solid waste management and resource recovery during the 4-crew 180-day CELSS integrated experiment

In order to explore the management and treatment methods of solid waste in the Controlled Ecological Life Support System (CELSS) of future lunar bases, during the 4-crew 180-day integrated experiment, the Solid Waste Management and Treatment System (SWMTS) was built, in which the treatment of recyclable solid waste such as inedible plant parts and human excrement was completed through a combination of biological aerobic composting and high-temperature oxidation. Basic data on the types and amounts of solid waste generated during the 4-crew 180-day experiment mission were obtained. There were six types of solid wastes, including the work support wastes, the household support wastes, the plant cultivation wastes, the plant-based wastes, and crew feces. The daily average production was 0.67, 1.4, 0.32, 8.48, 0.534 kg/d, respectively. The proportion of plant-based wastes was high as 74.3 %, indicating that it was the most important part. By closed-loop air drying and graded crushing, all 1526.97 kg of plant-based waste was treated, with water recovery (about 1163.87 kg), as well as volume reduction and stabilization treatment. By incineration and aerobic composting treatment, 67.3 % (244.4 kg) of the plant-based wastes (dry weight) and all of the feces (96.26 kg) were converted, providing 339.54 kg carbon dioxide for plant growth. And 90.6 kg organic fertilizer was obtained. The fertilizer was highly mature, met safety requirements, and effectively improved lettuce yield. The recycling rate of renewable solid waste during the experiment reached 89.8 %. The efficient circulation of solid waste had been achieved during the 4-crew 180-day integrated experiment. The long-time experimental results have shown that the established solid wastes management and treatment system can timely treat biomass solid waste such as inedible parts of plants and crew feces, achieve timely recovery of water in such solid waste, and recycle carbon and other elements, which effectively improved the material closure of the system and ensured the successful 4-crew 180-day experiment. This work also maybe lay the foundation for the construction and operation of an ecological life support system for future lunar bases.

Techno-economic assessment of electro-synthetic fuel based on solid oxide electrolysis cell coupled with Fischer–Tropsch strategy

Electro-synthetic fuel is proposed as an approach to achieve net-zero carbon emissions for heavy-duty internal combustion engines and meet carbon neutrality targets. This method is based on high temperature co-electrolysis using a solid oxide electrolysis cell (SOEC) coupled with Fisher-Tropsch (FT) synthesis due to its high efficiency and carbon recycling capacity. To access the techno-economic viability of this pathway and identify the key elements impacting the cost of electro-synthetic fuels, a comprehensive techno-economic model is constructed. This model aims to offer cost cutting guidance and includes SOEC, FT, and techno-economic sub-models, with SOEC and FT validated using literature data. The cost breakdown and sensitivity analysis indicate that heating costs, electricity prices, and stack lifetime are critical factors in reducing the cost of electro-synthetic fuel. Three alternative system layouts that fully utilize thermal and chemical energy are proposed to address the significant heating expense issue. Among these, the optimal system design lowers costs by approximately 5.3 %. Furthermore, this work introduces the contradiction between high performance, high stability, and low-cost accounting for the SOEC lifetime, which is bounded by operating current density. When considering the degradation and replacement of SOEC stacks, the long-term profitability of operating SOEC at a current density of 500 mA/cm2 is superior to that of 850 mA/cm2. Despite the most effective layout being currently unprofitable, it is anticipated that in the future, carbon trade, renewable electricity and technological advancements will drive the cost of electro-synthetic fuel to become competitive with that of diesel.

Solvolysis Process for Recycling Carbon Fibers from Epoxy‐Based Composites

AbstractFiber reinforced polymers boast exceptional mechanical performance coupled with low material density. Over recent decades, their usage has been steadily increasing and is poised to accelerate in the future. These materials typically have a lifespan of around 25–30 years, so at present time lots of tons of polymer composites are next to their end of life and this volume continues to grow. Currently, a significant portion of these materials is either incinerated or landfilled, resulting in substantial environmental impacts. Numerous studies have aimed to identify optimal recycling approaches, one of which involves solvolysis: the chemical dissolution of the polymer matrix. In this study, a solvolysis method has been devised and refined to effectively recover carbon fibers from composites while minimizing property degradation. The process begins with the identification of a suitable solvolysis fluid, specifically an aqueous sulfuric acid solution. Subsequently, key solvolysis parameters including solution concentration, temperature, residence time, and fluid agitation are meticulously optimized. The chemical and morphological impacts of this process are thoroughly examined using Fourier‐transform infrared spectroscopy analysis and scanning electron microscope observations.

Strong yet Tough Catalyst-Free Transesterification Vitrimer with Excellent Fire-Retardancy, Durability, and Closed-Loop Recyclability.

Despite great advances in vitrimer, it remains highly challenging to achieve a property portfolio of excellent mechanical properties, desired durability, and high fire safety. Thus, a catalyst-free, closed-loop recyclable transesterification vitrimer (TPN1.50) with superior mechanical properties, durability, and fire retardancy is developed by introducing a rationally designed tertiary amine/phosphorus-containing reactive oligomer (TPN) into epoxy resin (EP). Because of strong covalent interactions between TPN and EP and its linear oligomer structure, as-prepared TPN1.50 achieves a tensile strength of 86.2MPa and a toughness of 6.8MJm-3, superior to previous vitrimer counterparts. TPN1.50 containing 1.50 wt% phosphorus shows desirable fire retardancy, including a limiting oxygen index of 35.2% and a vertical burning (UL-94) V-0 classification. TPN1.50 features great durability and can maintain its structure integrity in 1M HCl or NaOH solution for 100 days. This is because the tertiary amines are anchored within the cross-linked network and blocked by rigid P-containing groups, thus effectively suppressing the transesterification. Owing to its good chemical recovery, TPN1.50 can be used as a promising resin for creating recyclable carbon fiber-reinforced polymer composites. This work offers a promising integrated method for creating robust durable fire-safe vitrimers which facilitate the sustainable development of high-performance polymer composites.

Flexural behavior of pre-damaged RC beams strengthened with UHPFRC-CFRP grid layer

Ultra-high performance fiber reinforced concrete (UHPFRC) using recycled tyre fibers and carbon fiber-reinforced polymer (CFRP) grid were combined to strengthen the pre-damaged reinforced concrete (RC) beams caused by coupling action of sustained loads and marine environment. The flexural tests were conducted to investigate failure modes, characteristic loads, deflection features, and strain behavior of the strengthened RC beams with different configurations. The results showed that they exhibited the typical bending failure without interfacial debonding, and their cracking, yield, and ultimate loads increased by 64.7 %−152.9 %, 105.7 % to 192 %, and 65.4–131.2 % compared with that of the RC beam (B0). By increasing the thickness of the UHPFRC layer and adopting the Y-type UHPFRC (using recycled tyre fibers), the stiffness, ductility, and synergistic performance among the main materials would be further improved, while the increase of the CFRP grid layers would decrease the ductility. Furthermore, analytical models considering the coupling action of sustained loads and marine environment were developed to calculate the characteristic loads, manifesting reasonable accuracy. The proposed UHPFRC-CFRP grid strengthening method has excellent mechanical and durability performance, cost-effectiveness, and environmental benefits, which can serve as a valuable reference for the innovation and development of structural strengthening technology.

Capacitive Sensors Based on Recycled Carbon Fibre (rCF) Composites.

Recycled carbon fibre (rCF) composites are increasingly being explored for applications such as strain sensing, manufacturing of automobile parts, assistive technologies, and structural health monitoring due to their properties and economic and environmental benefits. The high conductivity of carbon and its wide application for sensing makes rCF very attractive for integrating sensing into passive structures. In this paper, capacitive sensors have been fabricated using rCF composites of varying compositions. First, we investigated the suitability of recycled carbon fibre polymer composites for different sensing applications. As a proof of concept, we fabricated five touch/proximity sensors and three soil moisture sensors, using recycled carbon fibre composites and their performances compared. The soil moisture sensors were realised using rCF as electrodes. This makes them corrosion-resistant and more environmental-friendly, compared to conventional soil moisture sensors realised using metallic electrodes. The results of the touch/proximity sensing show an average change in capacitance (ΔC/C~34) for 20 mm and (ΔC/C~5) for 100 mm, distances of a hand from the active sensing region. The results of the soil moisture sensors show a stable and repeatable response, with a high sensitivity of ~116 pF/mL of water in the linear region. These results demonstrate their respective potential for touch/proximity sensing, as well as smart and sustainable agriculture.

Cation‐Infused Bilayer Ionomer Coating Enables High Partial Current Density Toward Multi Carbon Products in CO2 Electrolysis

AbstractElectrochemical CO2 reduction (eCO2R) stands as a pivotal technology for carbon recycling by converting CO2 into value‐added products. While significant strides have been made in generating multi‐carbon (C2+) products like ethylene (C2H4) and ethanol (C2H5OH) at industrial‐scale current densities with high Faradaic efficiency (FE), cathode flooding and (bi)carbonate salt accumulation remain a fundamental concern in an alkaline electrolyte. In this work, ion‐conducting polymers are used to tailor the micro‐environment mitigating cathode flooding and salt precipitation and thus, enhancing the local CO2 availability. The impact of cation and anion exchange ionomer layers, specifically Nafion and Sustainion XA‐9 are examined on overall eCO2R performance. The use of an ultra‐thin bilayer configuration significantly reduces cathode flooding and salt accumulation by ≈58% compared to commercial anion exchange membrane (AEM). Alongside, cation infusion improves the C─C bond formation inducing a favorable micro‐environment for selective C2+ formation. This cation‐infused bilayer ionomer (CIBLI) achieves a high partial current density of ≈284 mA cm−2 toward C2+ products maintaining a stable eCO2R performance for 24 hours (h). This scalable approach of directly deposited ultra‐thin CIBLI offers a minimal conversion energy of 117 GJ/ ton C2+ products with an energy efficiency (EE) of 29% at 350 mA cm−2 current density in one‐step CO2 conversion.

“Blooming” of litter-mixing effects: the role of flower and leaf litter interactions on decomposition in terrestrial and aquatic ecosystems

Abstract. The diversity effect on decomposition, through the litter-mixing effects plays a central role in determining the nutrient and carbon dynamics in ecosystems. However, the litter-mixing effects are centered on a leaf litter perspective. Important aspects related to intraspecific interaction and biomass concentration are rarely evaluated, even though they could be essential to determine the litter decomposition dynamics. To our knowledge, we introduced a new perspective to evaluate whether and how the interaction between flower and leaf litter affects the occurrence, direction, and magnitude of litter-mixing effects in terrestrial and aquatic ecosystems. We performed laboratory experiments using flower and leaf litter from the yellow trumpet tree Tabebuia aurea (Silva Manso) Benth. and Hook. f. ex. S. Moore as a model. To obtain realistic results, we manipulated various scenarios of flower : leaf litter biomass proportion and measured 13 functional traits. Litter-mixing effects were consistent in both aquatic and terrestrial environments, with faster decomposition of both litter types in mixtures compared to their monocultures (synergistic effects). Litter-mixing effects were stronger in the terrestrial environment and at higher flower : leaf litter biomass proportions. Our results indicate that synergistic outcomes are mainly associated with complementary effects. Flower litter had a higher concentration of labile C compounds, N, P, and K and lower lignin concentrations, representing a labile litter, while leaf litter had a higher concentration of lignin, Ca, Mg, and Na, representing a refractory litter. Our results demonstrate the importance of litter-mixing effects between flower and leaf litter via complementary effects. These results shed light on the secondary consequences of flower litter on decomposition, suggesting that species with high reproductive investment in flower biomass may play an important role in the nutrient and carbon recycling of diverse plant communities, exerting a pivotal role in biogeochemical dynamics.

Recyclable azine polyurethane thermosets and carbon fiber reinforced composites with excellent thermostability and mechanical properties

Carbon fiber reinforced composites (CFRCs) have received increasingly concerns and widely used in high-end applications, owing to their outstanding mechanical properties. Most of the polymers used in CFRCs were thermosets. However, a large number of applications brought enormous wastes due to the stable structure of thermosets which is difficult to degrade or recycle. CFRCs based on dynamic covalent polymers (DCPs) were developed to resolve the recycling problem. Polyurethanes were used for fabricating CFRCs applied in energy absorbing materials, vehicle interiors, sporting goods, and constructing materials, owing to excellent toughness, bonding abilities and low VOCs. Although some recyclable PU CFRCs were developed to resolve the recycling of CFs, there remain the problems of excess catalysts, low chemical resistance or thermostability due to the dynamic feature of DCPs. Herein, a series of azine polyurethane thermosets (APUTs) were prepared from hexamethylene diisocyanate (HDI) trimer and dihydroxy azines with different lengths of carbon chains. The resulting APUTs displayed excellent thermal stabilities with all Td, 5 % exceeding 320 °C, owing to high exchange temperature of azine moieties and high crosslinking density. APUTs-6 showed the highest tensile strength of 36.72 ± 1.18 MPa. APUTs-6 could be easily degraded in 0.1 M acetone/water solution at 50 °C. APUTs-6 showed excellent reprocessing properties and tensile strength could maintain 83.1 % of its initial one. The APUTs-6/CFs composites exhibited excellent mechanical properties, chemical resistance and recyclability. CFs could be readily recycled by acid degradation and maintain excellent mechanical properties. The tensile strength of recycled composites could recover 94.36 % of the original one after two times of recycling. The recovery ratio of tensile strength of recycled CF filaments was 95.7 %. The application of phenyl azine provided a feasible solution for the industrialization of recyclable CFRCs.

Nitrogen‐Doped Carbon‐Encapsulated Nickel Nanoparticle Catalysts Using Covalent Organic Frameworks as Templates for Electrochemical CO2 Conversion

AbstractElectrochemical CO2 reduction (ECR) reactions, powered by cleaner energy, possess significant promise in mitigating CO2 emissions and achieving carbon recycling. Herein, Ni@N‐C electrocatalysts with encapsulated structures are prepared using covalent organic frameworks (COFs) as templates, where COF‐derived nitrogen‐doped carbon (N‐C) is utilized to wrap Ni nanoparticles. At the potential of −0.97 V vs. RHE, 2Ni@N‐C‐800 is characterized by a high current density (j = 24.2 mA cm‐2) and relatively high CO Faraday efficiency (FECO = 72%), reflecting its good catalytic activity. The ECR performance of 2Ni@N‐C‐800 is due to the cooperative interaction between Ni nanoparticles and the N‐C structure, which is inferred from control and poisoning measurements. This study provides a new idea for finding efficient and stable ECR catalysts.