Hybrid Carbon Research Articles

Zirconium-based metal–organic frameworks/porous carbon hybrids as high-performance anode materials for highly stable lithium- and potassium-ion batteries

Metal-organic framework (MOF)-derived carbon materials have been widely investigated as advanced electrode materials. However, post-synthetic modifications suffer from certain limitations in morphology, surface area, and pore size control. Herein, we report a simple strategy to synthesize surface-confined Zirconium(Zr)-based MOF UiO-66-NH2 carbon hybrids (Zr-MOF@C; denoted as Zr-MOF, Zr-MOF@C10, Zr-MOF@C25, and Zr-MOF@C50) through a covalent assembly/amide linkage between the MOFs and hierarchical porous carbon (PC) in various proportions under solvothermal conditions. Zr-MOF@C hybrids have been utilized as the anode materials for lithium- (LIBs) and potassium-ion batteries (KIBs). In LIBs, the Zr-MOF@C10, Zr-MOF@C25 and Zr-MOF@C50 anodes delivered the discharge capacities of 126, 65 and 94 mA h g−1 at 100 mA g−1 after 100 cycles, respectively. In KIBs, the Zr-MOF@C10 and Zr-MOF@C25 exhibited the high discharge capacities of 78 and 70 mA h g−1 at 100 mA g−1 over 100 cycles. In addition, the Zr-MOF@C25 and Zr-MOF@C50 anodes exhibited an outstanding rate capability with a reversible capacity of ∼166 mA h g–1 vs. K/K+ and 176 mA h g–1 for Li/Li+, respectively, while well-maintained long-term cyclic stabilities of ∼57 mA h g–1 (Zr-MOF@C25 vs. K/K+) and ∼140 mA h g–1 (Zr-MOF@C50 vs. Li/Li+) at 1 A g–1 over 1000 cycles. The electrochemical kinetics studies revealed that Li+ and K+ storage efficiencies of all anodes were dominated by a surface-charge capacitive effect and diffusion-driven charge storage mechanism, respectively. These findings provide new insights for designing high-performance surface-confined MOF-based carbon composite materials for next-generation high-energy storage devices.

A novel approach for the facile synthesis of zinc oxide/carbon hybrid systems from corn distillers soluble: Surface modification and characterization for sustainable remediation

Sustainable, efficient, and environmentally friendly ways to tailor the carbonaceous materials from bio sources with desired functionalities remain a challenge around the world. In this study, we represent a novel approach to synthesize carbon hybrid material based on Zinc Oxide/carbon (ZnO/C) hybrid systems by catalytic hydrothermal process via crosslinking reaction through nucleation and growth of ZnO particles at the functional groups of oxidized carbon material. This research explored the volarization of Condensed Corn Distillers Soluble (CDS) as a carbon precursor to synthesize biobased carbon spheres. Surface modification of the produced carbon spheres took place using zinc chloride (ZnCl2) during hydrothermal carbonization (HTC). Zinc chloride (ZnCl2) was used to function as a catalyst during HTC and functioned as a ZnO source to synthesize (ZnO/C) hybrid systems. Design Expert software v13 was used to design the hydrothermal carbonization (HTC) experiments and response surface methodology was used to find the optimized conditions for the preparation of carbon hybrid systems. The hydrothermal synthesis process introduced 3D stone like zinc oxide particles onto the carbon matrix. These particles were self-assembled onto the carbon framework to produce carbon hybrid systems with unique physical, chemical, structural and functional properties. Herein, the obtained carbon hybrid systems (ZnO/C) were investigated and discussed in detail. ZnO/C hybrid systems were analyzed for surface morphology using scanning electron microscopy (SEM) that presented a 3D spherical interconnected phase and XRD analyses were used for phase crystallinity that showed new crystalline phases such as hopeite and zincite after the ZnCl2 incorporation. Surface functional groups were also analyzed by FTIR and results confirmed the presence of hydrophilic groups such as –OH, CC, and COOH on the surface of ZnO/C hybrid carbon systems. This study provided the insightful guidance for tailoring novel design of multifunctional carbon material as an adsorbent/catalyst for various applications of sustainable remediation.

Switching Behavior of the Composite Low Dimensional Structural Hybrids of Carbon After UV Exposure

Low dimensional multi structural components of carbon are of great interest currently owing to their applications in developing flexible plastic electronics. In this work, we discuss emergence of different structural hybrids of carbon from as-prepared HiPCO SWCNTs subjecting them to oxidative acid purification and covalent functionalization process. Transmission electron microscopy (TEM) investigations reveal single wall carbon nanotubes (SWCNTs) serve as a building block to obtain multi wall carbon nanotubes (MWCNTs), graphene sheets (GS), carbon nano scrolls (CNS) structures which coexist in the sample. These structures when grafted with polymer binder and spray coated on Si substrate provide highly sustainable thin film coatings that are stable even in adverse space conditions [1]. These CNT and CNS based composite coatings are promising candidates for stray light control space applications exhibiting a low reflectance of the order of 2-3% in the visible spectral range [1]. Electrical switching behaviour of these films were investigated by capturing current(time) (I(t)) response, displaying promising switching character with distinct ON-OFF cycle. These coatings offer opportunities for the development of facile, cost-effective carbon-based devices without going into the nontrivial task of separating different the structures.

Lotus Root Type Nickel Oxide-Carbon Nanofibers: A Hybrid Supercapacitor Electrode Material

In this study, we investigate the electrochemical properties of a nickel oxide-carbon (NiO/C) material, synthesized in the form of highly porous carbon nanofibers through the electrospinning of polymers such as polyacrylonitrile (PAN) and polystyrene (PS) followed by a carbonization process. The primary focus of this work is to determine the optimal mixing ratio for the hybrid material composed of NiO and carbon. While it is widely acknowledged that supercapacitor materials benefit from having a high specific surface area, our findings reveal that hybrid carbon nanofibers with a 45% specific carbon-to-nickel oxide ratio exhibit significantly enhanced capacitance (39.9 F g−1). This outcome suggests the promising potential of our materials as an energy storage material for hybrid supercapacitors, combining the advantages of electric double-layer capacitors (EDLC) and Pseudo capacitors (Pseudo).

Investigating Hydrocarbon Gases Permeability Through Hollow Fiber Hybrid Carbon Membrane

Hydrocarbon separation from natural gases is a critical procedure in the chemical and petrochemical industries. This study used hollow fiber carbon membranes (HFCMs) made from a commercially available co-polyimide, P84, with zeolite-carbon composite (ZCC) as a filler to separate light hydrocarbons like CH4/C3H8 and CH4/C2H6. The Arrhenius technique was used to evaluate the effects of temperature fluctuations (298, 323, and 373 K) on the membrane. X-ray diffraction exhibited a characteristic graphite peak at 2θ ~ 44°, indicating the creation of an effective carbon membrane. SEM investigation revealed the compactness of both pristine and hybrid carbon membrane structures. The operating temperature has a significant influence on the gas penetration through the membrane when evaluating gas permeation. The hybrid carbon membrane has the highest permeability for CH4, C2H6, and C3H8 at 373 K. (81.86, 61.82, and 58.28 Barrer, respectively). The carbon membrane also showed greatest selectivity for CH4/C3H8 and CH4/C2H6 at 323 K (2.24 and 2.04, respectively). Adsorption and surface diffusion were the membrane's transport mechanisms. By adding filler to the membrane, the gas permeability was temperature dependent.

Catalytic effect of metal alloy sublayers on graphene formation in thermally annealed amorphous carbon ultrathin films

The exceptional properties of graphene, such as mechanical strength, flexibility, thermal conductivity, electron mobility, biocompatibility, and transparency, make it an ideal material for numerous applications. The objective of this study was to develop a one-step process of graphene formation that uses inert thermal annealing of amorphous carbon (a-C) ultrathin films deposited onto different metal catalyst sublayers to transform highly sp3 hybridized a-C nanostructures within the film to sp2 hybridized graphene nanostructures. To elucidate the mechanism of graphene formation and the catalytic effect of the sublayers on sp3-to-sp2 transformation, Si/FeNi/a-C and Si/FeCo/a-C stacks were fabricated by physical vapor deposition techniques. X-ray photoelectron and Raman spectroscopies were used to analyze the structure of as-deposited and thermally annealed a-C films. Moreover, molecular dynamics simulations provided insight into graphenization at the atomic level. The sp3 fraction of as-deposited a-C films was found to play a pivotal role in the formation of graphene during thermal annealing. The carbon concentration in the catalyst sublayers and the compressive stress in the a-C films strongly affected atomic carbon hybridization and, consequently, the graphene quality. Differences in the catalytic effectiveness of the sublayers in producing graphene are interpreted in terms of the sublayer carbon concentration, atomic packing, and electronic structure of the valence band of elements affecting the interaction between carbon and transition metals, ultimately influencing graphene nucleation.

The pioneer of intelligent and sustainable construction in tunnel shotcrete applications: a comprehensive experimental and numerical study on a self-sensing and self-heating green cement-based composite

In this study, a self-sensing and self-heating natural fibre-reinforced cementitious composite for the shotcrete technique was developed using Kenaf fibres. For this purpose, a series of Kenaf fibre concentrations were subjected to initial chemical treatment, followed by integration into the cement-based composite containing hybrid carbon nanotubes (CNT) and graphene nanoplatelets (GNP). The investigation encompassed an examination of mechanical, microstructural, sensing, and joule heating performances of the environmentally friendly shotcrete mixture, with subsequent comparisons drawn against a counterpart blend featuring a conventionally synthesized polypropylene (PP) fibre. Following the experimental phase, a comprehensive 3D nonlinear finite difference (3D NLFD) model of an urban twin road tunnel, completed with all relevant components, was meticulously formulated using the FLAC3D (fast lagrangian analysis of continua in 3 dimensions) code. This model was subjected to rigorous validation procedures. The performances of this green shotcrete mixture as the lining of the inner shell of the tunnel were assessed comparatively using this 3D numerical model under static and dynamic loading. The twin tunnel was subjected to a harmonic seismic load as a dynamic load with a duration of 15 s. The laboratory findings showed a reduction in the composite sensing and heating potentials in both cases of Kenaf and PP fibre reinforcement. Incorporating a specific quantity of fibre yields a substantial enhancement in both the mechanical characteristics and microstructural attributes of the composite. An analysis of digital image correlation demonstrated that Kenaf fibres were highly effective in controlling cracks in cement-based composites. Furthermore, based on the static and dynamic 3DNLFD analysis, this green cement-based composite demonstrated its potential for shotcrete applications as the lining of the inner shell of the tunnel. This study opens an appropriate perspective on the extensive and competent contribution of natural fibres for multifunctional sustainable, reliable and affordable cement-based composite developments for today’s world.

Fe2O3-Kao@g-CN activated peroxymonosulfate remediation of bensulfuron methyl-polluted water and soil: Detoxification, soil properties and crop growth

Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) have been frequently applied in environment remediation for the rapid degradation of organics, while the high PMS usage could increase economic cost and ecological risks. Therefore, efficient activation methods are highly needed. In this study, low cost and environmentally safe bi-mineral hybrid carbon Fe2O3-Kao@g-CN was designed and fabricated to efficiently activate PMS for the remediation of water and soil polluted by bensulfuron methyl (BSM). Specifically, the Fe2O3-Kao@g-CN/PMS system could utterly remove BSM from water within 90 min and showed satisfactory tolerance to environment variation. The toxic BSM could be degraded into 15 kinds of intermediates with lower toxicity, benefiting from various reactive species of SO4•−, O2•−, •OH and 1O2. Furthermore, the removal efficiency of BSM in polluted wheat and maize soil reached about 79.2 %-86.8 % with low doses of PMS (3.07 mg·g−1) and catalyst (2 %). The degradation system did not adversely affect the soil pH and the soil redox potential (Eh), while promoted soil potassium availability and crop growth. The biomass and length of wheat and maize in remediated soil was significantly increased by 26.2 %-346.4 % compared with those planted in BSM-contaminated soil. This work emphasized the application of Fe2O3-Kao@g-CN/PMS system for BSM detoxification in water and soil and its ecological risks, offering a theoretical and practical foundation for decreasing environment risk and ensuring crop growth in the environment remediation.

Nonthermal plasma coupled with Mn/N-doped carbon catalysts for highly efficient removal of toluene

In order to ensure the excellent performance of a nonthermal plasma (NTP)-catalysis system, a highly efficient catalyst is generally required. In this study, nitrogen-enriched hollow hybrid carbon (N-C) catalysts were designed, synthesized through facile pyrolysis of a zeolitic imidazolate framework precursor, and used as a support on which to disperse Mn species. Notably, the coupling of NTP with the Mn/N-C catalysts resulted in strong activity. Mn loading of 6 % was found to remove almost all toluene (98 % efficiency) and to have COx selectivity (82.1 %) when the specific energy density (SED) value was 252 J·L−1; when the SED value was 102 J·L−1, the energy yield was 10.6 g·kWh−1. The performances of the developed Mn/N-C catalysts were related to their highly dispersed nature and strong ability to activate oxygen and dissociate O3. Hereafter, the toluene decomposition pathway is described. The present findings demonstrate the potential applications of porous N-C-supported metal oxide catalysts in the removal of volatile organic compounds through a catalyzed NTP process.

Activity and stability of electrochemically reduced graphene oxide films for applications requiring mixed conductivity

A protonic and electronic conductor composed of partially reduced graphene oxide (GO) has been prepared by electrochemical methods. Conductivity measurements and detailed surface analysis by XPS, FTIR, and Raman methods show that the electrochemically reduced GO (ERGO), prepared under different reduction potentials, exhibits a unique dual (protonic and electronic) conductivity which is tunable by adjusting the surface conditions. Selected removal of the oxygenated groups, evolution of C(sp2)/C(sp3) hybrid carbon structure, and surface structure of ERGO can impact the protonic and electronic transport mechanisms. The ERGO samples reported here are ideal support materials with proper ratios of protonic and electronic transport. The as-prepared ionomer-free and flexible ERGO-supported Pt (Pt/ERGO) electrodes were characterized for oxygen reduction reaction (ORR) reactivity in acidic solution. The results showed not only higher electrochemical surface area (ECSA), but also improved mass activity towards ORR compared to conventional carbon supported Pt catalysts.

MICROSTRUCTURE OF CB/SIO2 HYBRID REINFORCED SOLID TYRE TREAD COMPOUND CONTAINING GROUND TYRE RUBBER AND THEIR EFFECT ON FATIGUE RESISTANCE

The possibility of improving the properties of rubber compounds containing ground tyre rubber (GTR) is an active research area. This study investigates the microstructure of carbon black filled tyre tread compound containing 20 phr GTR and compares the microstructure with those of similar compounds reinforced with hybrid carbon black/precipitated silica (CB/SiO2). In the compounds reinforced with hybrid filler, amount of the GTR was maintained at 20 phr, while the amount of the hybrid filler (CB/SiO2 ) were in the ratios 55/5, 50/10 and 45/15 respectively. The compounds were mixed by two-step mixing method using internal mixer and two-roll mill. The vulcanisation of each rubber compound was carried out on a compression moulding machine at 150. Results obtained from scanning electron microscopy of the fractured surfaces showed that the ingredients in the control sample that was not filled with GTR were well dispersed and distributed. The micrograph of the sample containing GTR and mixed at 60 showed that GTR was not very compatible with the matrix. Improved mixing was achieved with increased mixing temperature. The addition of precipitated silica at 5 phr resulted in poor dispersion. The dispersion improved as the amount of silica increased to 10 phr and 15 phr respectively. Results obtained from flex fatigue test show that the compounds filled with hybrid CB/SiO2 in the ratios 50/10 and 45/15 phr exhibited no crack after 1000 cycles due to good dispersion. It is recommended that hybrid CB/SiO2 reinforcement at optimal amount of silica should be utilised to fill rubber compounds containing GTR in order to improve the properties of the vulcanisates.

Further treatment of coking wastewater treated in A2O-MBR by the nanofiltration-powder activated carbon hybrid system.

In this study, further treatment of coking wastewater treated in anoxic-oxic-membrane bioreactor (A2O-MBR) was investigated to meet the standards of the ministry by means of nanofiltration (NF) (with two different membranes and different pressures), microfiltration -powder activated carbon (MF-PAC) hybrid system and NF-PAC (with two different membranes and five different PAC concentrations) hybrid system. In addition to the parameters determined by the ministry, other parameters such as ammonium, thiocyanate (SCN-), hydrogen cyanide (HCN), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), color were also examined to evaluate the flux performance and treatment efficiency of the hybrid processes. According to the results, chemical oxygen demand (COD) in the NF process, COD and total cyanide (T-CN) in the MF-PAC process could not meet the discharge standards. As for the NF-PAC hybrid system, XN45 membrane met the discharge standards in all parameters (COD = 96±1.88 mg/L, T-CN =<0,02 mg/L, phenol =<0.05 mg/L), with a recovery rate of 78% at 0.5 g/L PAC concentration.

Phase change materials encapsulated in a novel hybrid carbon skeleton for high-efficiency solar-thermal conversion and energy storage

Phase change materials (PCMs) with high energy density and stationary transition temperature are now considered promising solar energy storage mediums. However, their intrinsic poor light absorption, thermal conductivity and stability severely impede their potential applications. In this study, a novel carbonized hybrid aerogel (CHA) structure was firstly constructed by incorporating MXene and carbon nanofibers (CNFs) into a continuous phase polyamic acid salt (PAAS) aqueous solution, followed by directional freezing, vacuum drying, imidization, and carbonization processes. Finally, the composite PCMs (CPCMs) were fabricated by vacuum impregnation of PCMs into the CHAs. The CPCM, of which CHA consists of 20 wt% MXene and 10 wt% CNF@PDA, demonstrates high solar-thermal conversion efficiency (>91 %), improved thermal conductivity of 0.40 W·m−1·K−1, great thermal stability (enthalpy loss < 0.19 % after 100 cycling tests with no obvious leakage). The introduction of MXene and CNFs endows PCM with broader light absorption spectrum range. The skeleton matrix embedded with bonded MXene sheets and CNFs provides more thermal pathways, light absorption sites and carrying capacity, improves the thermal conductivity, solar-thermal conversion property and stability of PCM. In addition, CPCM also exhibits outstanding EMI SE (95 dB). The multifunctional and high-performance CPCMs shows potential to realize the effective capture and utilization of solar energy. This work provides a new strategy to construct stable and multifunctional hybrid carbon skeleton for high-efficiency solar-thermal conversion and energy storage.

Precursor Symmetry Triggered Modulation of Fluorescence Quantum Yield in Graphene Quantum Dots

AbstractAlthough various effective machine‐learning attempts have been made to investigate the photoluminescence properties of graphene quantum dots (GQDs) or carbon dots, the physical correlation behind their mathematical models has not been reasonably elucidated. In this work, the correlation mechanism between the precursor structure and quantum yield of GQDs prepared by a “bottom‐up” method is sufficiently studied. Three decisive factors affecting the quantum yield of GQDs during the two‐component reaction system preparation are revealed, namely structure factor (F1), temperature factor (F2), and concentration factor (F3). The symmetry of precursors in the formation of sp2–sp3 hybrid carbon nanostructures is considered the key factor in the modulation of fluorescence quantum yield in GQDs. Notably, in contrast to previous work, it is first demonstrated that the normal modes of molecular vibration are the core mechanism by which the structural properties of the precursors act on the fluorescence quantum yield of GQDs. The conclusion further proved conducive in obtaining GQDs with a higher absolute quantum yield up to 83.33%.

REVIEW OF CARBON PRICING MECHANISMS: EFFECTIVENESS AND POLICY IMPLICATIONS

The escalating threat of climate change has intensified the need for robust strategies to reduce greenhouse gas emissions. Carbon pricing mechanisms have emerged as pivotal tools in this endeavor, aiming to internalize the external cost of carbon emissions and incentivize cleaner, more sustainable practices. This review provides a comprehensive analysis of various carbon pricing mechanisms, evaluating their effectiveness and exploring the policy implications for future implementations. The review categorizes carbon pricing mechanisms into three main types: Carbon Taxes, Cap-and-Trade Systems, and Hybrid Approaches. Each mechanism is examined in terms of its characteristics, case studies from jurisdictions that have implemented them, and a critical assessment of their effectiveness and challenges. The paper evaluates the impact of carbon pricing mechanisms on economic sectors, assessing their influence on industry and their role in stimulating innovation. Furthermore, it scrutinizes the effectiveness of these mechanisms in achieving emission reductions, considering their impact on greenhouse gas emissions. Additionally, the review delves into the social and distributional impacts of carbon pricing, analyzing its equity aspects and identifying potential challenges. Drawing from implemented policies, the review extracts valuable lessons and insights. It explores the integration of carbon pricing with other climate policies, examining synergies and coordination possibilities. The discussion also includes the potential for global cooperation and harmonization, recognizing challenges and opportunities for aligning international efforts. As a forward-looking aspect, the paper explores innovative approaches to carbon pricing, considering technological advancements and market-based solutions. It concludes with policy recommendations aimed at enhancing the effectiveness of carbon pricing mechanisms, addressing challenges, and providing insights for policymakers and stakeholders. This review consolidates current knowledge on carbon pricing mechanisms, shedding light on their effectiveness and unveiling important policy implications. By synthesizing lessons learned from implemented policies, the paper contributes to the ongoing discourse on effective climate change mitigation strategies, emphasizing the role of dynamic, adaptable, and equitable carbon pricing mechanisms.&#x0D; Keywords: Carbon Pricing, Mechanisms, Climate change mitigation, Effectiveness, and Policy Implications.

Advances in Biological Wastewater Treatment Processes: Focus on Low-Carbon Energy and Resource Recovery in Biorefinery Context.

Advancements in biological wastewater treatment with sustainable and circularity approaches have a wide scope of application. Biological wastewater treatment is widely used to remove/recover organic pollutants and nutrients from a diverse wastewater spectrum. However, conventional biological processes face challenges, such as low efficiency, high energy consumption, and the generation of excess sludge. To overcome these limitations, integrated strategies that combine biological treatment with other physical, chemical, or biological methods have been developed and applied in recent years. This review emphasizes the recent advances in integrated strategies for biological wastewater treatment, focusing on their mechanisms, benefits, challenges, and prospects. The review also discusses the potential applications of integrated strategies for diverse wastewater treatment towards green energy and resource recovery, along with low-carbon fuel production. Biological treatment methods, viz., bioremediation, electro-coagulation, electro-flocculation, electro-Fenton, advanced oxidation, electro-oxidation, bioelectrochemical systems, and photo-remediation, are summarized with respect to non-genetically modified metabolic reactions. Different conducting materials (CMs) play a significant role in mass/charge transfer metabolic processes and aid in enhancing fermentation rates. Carbon, metal, and nano-based CMs hybridization in different processes provide favorable conditions to the fermentative biocatalyst and trigger their activity towards overcoming the limitations of the conventional process. The emerging field of nanotechnology provides novel additional opportunities to surmount the constraints of conventional process for enhanced waste remediation and resource valorization. Holistically, integrated strategies are promising alternatives for improving the efficiency and effectiveness of biological wastewater treatment while also contributing to the circular economy and environmental protection.

Designed and Analysed of Three Distinct Composite Material-Based Mano Leaf Spring using ANSYS

The leaf spring is an important component in vehicles because it provides a comfortable ride and stability to the vehicle. The need to replace leaf springs with stronger and more lasting leaf springs is a key challenge in the transportation and automotive industries. In addition to offering ride comfort and stability, traditional steel leaf springs have a significant impact on the weight of the car. Fibre reinforced polymeric composites, therefore, are appropriate materials for various applications due to their many exceptional properties, including high wear resistance, high strength, long fatigue life, corrosion resistance, and low density. Fiber-reinforced polymeric composites find extensive application in several technical sectors, such as automotive, aviation, military, and marine industries. The utilization of composite materials has become imperative in the automotive industry to attain weight reduction without compromising material strength, as fuel consumption and CO2 emissions have to be reduced. In this paper, three different types of composite-based mono leaf springs were designed and examined. The results of the investigations showed that the 0° unidirectional glass fiber system was unable to correctly produce the required spring rate. Consequently, many combinations of carbon and glass hybrid systems were studied. The analysis showed that the desired spring rate was produced by the material configuration of [0°6G / 0°2C / 0°22G] S. When the final results were contrasted with the FEA findings, it was found that they concurred.

Experimental behaviour of hybrid carbon steel – stainless steel bolted connections subjected to electrochemical corrosion

To minimise cost in practical applications whilst still obtaining a satisfactory performance, stainless steel is often employed in aggressive marine environments to ensure the durability of the structure, whilst parts of the structure less susceptible to corrosion employ conventional carbon steel. When the two materials are in direct contact in the connection region, galvanic corrosion can occur over time thus leading to an increased level of corrosion of the less noble carbon steel parts and an associated degradation in the structural performance. A comprehensive experimental study on the shear behaviour of hybrid carbon steel – stainless steel bolted connections subjected to electrochemical corrosion is presented in this paper. A total of 30 bolted connection specimens were designed and assembled from hot-rolled carbon steel and stainless steel plates. Two bolt grades, the high strength bolts 10.9 and the precipitation hardening stainless steel bolts 10.9 were used to connect the plates. Employing the electrochemical corrosion method, the specimens were subjected to various levels of corrosion by adjusting the duration over which the specimens were sunk in the corrosive medium, which resulted in both different corrosion morphology as well as different levels of mass loss of the carbon steel plates due to corrosion. The corroded connection specimens were thereafter tested to failure under shear exhibiting 4 different failure modes. The load versus deformation curves were recorded and are reported herein, whilst the observed failure modes were also documented. It was revealed that increased level of corrosions led to decreased levels of bolt pretention forces and ultimate resistances of the connections, albeit the severity of the degradation strongly depended on the adopted joint configuration and resulting failure mode.

A novel approach for facile synthesis of cost-optimal catalyst for high-performance lithium-air battery

We have developed a novel and efficient cathode for advanced lithium-air batteries by employing a new approach and facile strategy. In this method, we prepared core-shell structured ZIF-8@ZIF-67 crystals with epitaxial growth using a hydrothermal technique. By subjecting these crystals to carbonization at a temperature 200 °C higher than the degradation initiation temperature (i.e. 600 °C according to thermogravimetric results), we successfully obtained functionalized nanoporous hybrid carbon materials. These hybrid carbon materials consist of hierarchical nitrogen-doped carbon @ cobalt anchored/nitrogen doped carbon (NC@CNC), where the nitrogen-doped carbon (NC) serves as the core and the cobalt anchored/nitrogen doped carbon (CNC) forms the shell. It is worth noting that electrochemical characterization data strongly support the superior performance of this nanoporous hybrid carbon material. It combines the advantageous properties of individual mesopores of nitrogen-doped carbon and the catalytic activity of cobalt‑nitrogen doped carbon. In particular, the cathode material, i.e. NC@CNC, exhibits a remarkable specific capacitance of 10,000 mAh·g−1, as calculated from the galvanostatic charge-discharge curves obtained at a current density of 50 mA·g−1. This impressive performance highlights the potential of our developed material in enhancing the efficiency and overall performance of lithium-air batteries.

Reinforcement of concrete beams using waste carbon-nanoclay-fiberglass laminate pieces

In the last few decades, strengthening of structures in need of repair with fiber reinforced polymer (FRP) composite materials produced with different fiber types has gained great importance. Within the scope of this experimental study, the usability of hybrid glass and carbon composite laminates produced for different purposes and later cut into waste was investigated for concrete reinforcement. Hybrid composite laminates were produced in the form of glass-carbon-glass and carbon-glass-carbon, and the effect was investigated in two different sequences in the study. In addition, there are 3 different rates of nanoclay (0.50%, 0.75% and 1.25%) in the production of composite materials, and the effect of nanoclay ratio was investigated. In the study, two different numbers of composite laminates were adhered to the concrete samples produced in 70x70x280 mm dimensions and subjected to flexural strength test. In the Carbon-Glass-Carbon series using triple waste laminate pieces, the highest flexural strength was reported in the CGC-0.75-3 series, which achieved an increase of approximately 55% and 42% compared to the Control and Control-E series. It was determined that the effectiveness of the reinforcement technique of concrete with laminates in flexure did not change significantly depending on the number of laminate pieces. The main mode of failure in the experimental work was due to concrete fracture.