Bifunctional Carbon Research Articles

A Tailored Bifunctional Carbon Catalyst for Efficient Glycosidic Bond Fracture and Selective Hemicellulose Fractionation

A Tailored Bifunctional Carbon Catalyst for Efficient Glycosidic Bond Fracture and Selective Hemicellulose Fractionation

Dual-excitation red-emissive carbon dots excited by ultraviolet light for the mitochondria-targetable imaging and monitoring of biological process in living cells

The bifunctional carbon dots (CA-p-CDs) with truly red-emission under short-wavelength light excitation (such as ultraviolet light, blue light or cyan light) were easily and successfully fabricated by attaching citric acid (CA) molecules onto the pristine p-CDs using an ultrasonic-triggered surface re-engineering approach under room conditions. Especially, the CA-p-CDs show truly red emission and excitation-wavelength-independent properties when excited by ultraviolet-light with a wavelength in the range of 360–400 nm or excited by progressively longer excitation wavelengths in the range of 440–500 nm. The CA-p-CDs were verified to be very low cytotoxicity. Importantly, the CA-p-CDs were further used for the targeted mitochondria imaging or direct evaluation on the intracellular biological process in living cells through variable PL emission colors with the gradually depletion of attached CA molecules. Furthermore, the strongest PL peaks of CA-p-CDs showed fluorescence enhancement response toward Cr3+ ions. The CA-p-CDs were also used for the highly sensitive and selective detection of Cr3+ ions in tap water with a limit of detection as low as 12 nM. This work presented designable fabrication of bifunctional CDs by linking molecules as an excellent nanoprobes for the mitochondria-targetable imaging and chemical sensing of heavy metal ions in water.

Bifunctional Carbon Nitride Exhibiting both Enhanced Photoactivity and Residual Catalytic Activity in the Post-Irradiation Dark Period

Graphitic carbon nitride (CN) as an environmental photocatalyst works under continuous illumination and stops under the dark condition. Here, we develop a bifunctional CN (4-phenoxyphenol-functiona...

Preparation of yellow-emitting carbon dots and their bifunctional detection of tetracyclines and Al3+ in food and living cells

A novel bifunctional carbon dot (CD)-based sensing platform was constructed for detection of tetracyclines (TCs) and Al3+. The fluorescence CDs were fabricated by hydrothermal method using phenylenediamine (p-PD) and ethylenebis(oxyethylenenitrilo) tetraacetic acid (EGTA) as precursors. The obtained prepared CDs show bright yellow fluorescence (y-CDs, EX = 400nm and Em = 556nm), high fluorescence quantum yield (QY = 21.55 ± 0.06%), and preferable optical stability. TCs can directly quench the fluorescence of y-CDs based on static quenching characteristics and a smallinternal filtration effect (IEF). By adding Al3+ to the y-CDs + TCs system, the fluorescence is partly recovered because TCs escape from the surface of the y-CDs and form a more stable chelate with Al3+. The sensing platform displays good selectivity and high sensitivity to TCs and Al3+ with low detection limits of 0.057-0.23μM and 0.091μM, respectively. Importantly, this sensing platform has enabledthe detection of TCs and Al3+ in milk samples with satisfactory recoveries and RSDs, confirming the reliability and feasibility of this method. Combining with low toxicity and preferable biocompatibility, the y-CDs are extended to cellular imaging and detection of CTC and Al3+ in A549 cells.

New bifunctional carbon material of metal‐free pomegranate peel catalyst and supercapacitor for highly efficient hydrogen production and energy storage

New bifunctional carbon material of metal‐free pomegranate peel catalyst and supercapacitor for highly efficient hydrogen production and energy storage

Sulfur-modified chitosan derived N,S-co-doped carbon as a bifunctional material for adsorption and catalytic degradation sulfamethoxazole by persulfate

N,S-co-doped carbons were synthesized through the calcination of sulfur-modified chitosan for the first time, and utilized as persulfate activators for sulfamethoxazole (SMX) remediation in water. The chitosan and sulfonyl chloride underwent one-step sulfonylation reaction to generate S-modified chitosan. The catalyst NSC-3 showed both excellent adsorption and catalytic oxidation efficiency, corresponding 98.62% removal and 81.34% mineralization rate within 90 min. The rate constant (kobs) was up to 0.0578 min−1, with 75.60-folders higher than that of sulfur-free catalyst NC (7.6580 ×10−4 min−1). The synergy of N and S contributed to the improvement of removal efficiency. The adsorption and oxidation performance were highly depended on the S/N atomic ratio. At the S/N ratio of 0.18, the maximum adsorption and oxidation capability were obtained. The NSC-3/PS system exhibited outstanding adaptability at the wide pH range from 3.07 to 9.28, while the inhibitory effect occurred at strong basic conditions (pH = 11.01). The thiophene sulfur and structural defects were identified as the catalytic sites in activating PS. Both radical and non-radical pathways were responsible for degradation process, where 1O2 played a major role, SO4·-exerted a minor contribution, and O2·- acts as the precursor for the production of 1O2. Another source of 1O2 was assigned to the activation of PS by structure defects. This work indicates that N,S-co-doped carbon at an optimal S/N atomic ratio effectively catalyzes persulfate, and provides an innovative method to construct bifunctional carbon materials of adsorption and oxidization.

Facile and Green Synthesis of Bifunctional Carbon Dots for Detection of Cu2+ and ClO– in Aqueous Solution

Devising novel water-soluble carbon dots (CDs) with a facile and economical process is pivotal for the detection of ions in the environment. In this paper, novel nanoscale CDs (polyethyleneimine-2,...

In-situ regeneration of tetracycline-saturated hierarchical porous carbon by peroxydisulfate oxidation process: Performance, mechanism and application

Carbonaceous material is not only the excellent adsorbent for organic contaminants removal, but also the effective activator for peroxydisulfate (PDS) activation. In this study, a nitrogen-doped hierarchical porous carbon material (NHGBC-800) presented the attractive bifunctional properties was developed for the removal of model organic contaminant antibiotic tetracycline (TC). On the one aspect, the NHGBC-800 had a large specific surface area (1178.0 m2/g) and achieved good TC removal with a maximal adsorption capacity (Qm) of 629.76 mg/g at 303 K. On the other aspect, TC-saturated NHGBC-800 could effectively activate PDS with itself as the activator, by which the mineralization of desorbed TC and in-situ regeneration of exhausted adsorbent were achieved simultaneously. The Qm of NHGBC-800 recovered 90.61% after first regeneration and still retained 77.18% even after the 6th adsorption-regeneration cycles. Moreover, the as-prepared material maintained good adsorption and regeneration performance under a wide range of pH conditions (3.02–9.83) and in the presence of inorganic anions such as Cl−, SO42−, NO3−, H2PO4−, HCO3−. The electro spin resonance (ESR), reactive oxygen species (ROS) quenching studies and electrochemical measurement revealed that the electron-transfer and single oxygen mediated the non-radical pathways dominated the TC degradation during the regeneration process. Compared with the conventional thermal and electrochemical regenerations, the in-situ regeneration of bifunctional carbon materials induced by PDS activation is more effective, sustainable and environmental-friendly.

Bifunctional carbon nanodots for highly sensitive HER2 determination based on electrochemiluminescence

Early detection of breast cancer increases the chances of achieving adequate and successful treatment as soon as possible. In this work, a promising disposable electrochemiluminescent immunosensor has been developed for simple, efficient detection of the HER2 protein, a breast cancer biomarker. Nitrogen-rich carbon nanodots were synthesized with two functions: to provide functional groups for covalent immobilization of HER2 antibodies and to act as co-reactants in the electrochemiluminescent process. The proposed immunosensor responded linearly to HER2 concentration over a wide range, showing a detection limit of 20.4 pg mL−1. The reliability of this biosensor was confirmed by analyzing HER2 in the presence of another tumor biomarker (CEA), as well as various proteins and sugars. In addition, this proposed strategy presented good stability and applicability in the analysis of human serum samples, showing great potential for applications in the early diagnosis of breast cancer.

Dehydration of glucose to 5-Hydroxymethlyfurfural on bifunctional carbon catalysts

The proposed study tries to reply on one important question concerning glucose dehydration: What is the role of bare or tandem Lewis/Brønsted acid sites in the reaction and which are better? A series of mono and bifunctional catalyst are designed and screened for the glucose dehydration reaction. The results clearly reveal that catalyst activity is a function of catalyst composition. The presence of Lewis sites the reaction toward first step isomerization, while the Brønsted acid dehydrate directly glucose to HMF via levoglucosane intermediate. This study proposed also a kinetic modelling of the included reactions and their contrast with the empirical observations.

Bifunctional Carbon Nanotube Yarns Fabricated Using Biscrolling Technology for Pseudocapacitors and Paramagnetic Actuators

Bifunctional Carbon Nanotube Yarns Fabricated Using Biscrolling Technology for Pseudocapacitors and Paramagnetic Actuators

Combined nanofiltration and advanced oxidation processes with bifunctional carbon nanomembranes.

Wastewater reclamation is becoming a top global interest as population growth and rapid industrialization pose a major challenge that requires development of sustainable cost-effective technologies and strategies for wastewater treatment. Carbon nanomembranes (CNMs)—synthetic 2D carbon sheets—can be tailored chemically with specific surface functions and/or physically with nanopores of well-defined size as a strategy for multifunctional membrane design. Here, we explore a bifunctional design for combined secondary wastewater effluent treatment with dual action of membrane separation and advanced oxidation processes (AOP), exploiting dissolved oxygen. The bifunctional membrane consists of a CNM layer on top of a commercial ultrafiltration membrane (Microlon™) and a spray-coated reduced graphene oxide (rGO) thin film as the bottom layer. The CNM/support/rGO membrane was characterized by helium ion and atomic force microscopy, FTIR, XPS with a four-point conductivity probe, cyclic voltammetry, galvanostatic measurements, and impedance spectroscopy. Combined treatment of water by nanofiltration and AOP was demonstrated, employing a unique three electrode-dead end filtration setup that enables concurrent application of potential and pressure on the integrated membrane. For the model organic compound methylene blue, oxidation (by the Fenton reaction) was evaluated using UV-vis (610 nm). The rejection rate and permeability provided by the CNM layer were evaluated by dissolving polyethylene glycol (400 and 1000 Da) in the feed solution and applying pressure up to 1.5 bar. This demonstration of combined membrane separation and AOP using an integrated membrane opens up a new strategy for wastewater treatment.

Bifunctional Carbon Dots Derived From an Anaerobic Bacterium of Porphyromonas gingivalis for Selective Detection of Fe3+ and Bioimaging.

In this study, for the first time, Porphyromonas gingivalis, an anaerobic bacterium, was selected to synthesize carbon dots. The achieved P.gingivalis-carbon dots (Pg-CDs) exhibited strong fluorescence and high stability with capability for dual function as Fe3+ sensor and intracellular imaging agent. The detection limit for Fe3+ was as low as 1.85µm. On the other hand, the prepared Pg-CDs were an excellent candidate for biosensor with high biocompatibility.

Cobalt phthalocyanine derived bifunctional carbon decorated CoSe with enhanced lithium storage capability

Transition-metal chalcogenides (TMCs) have attracted much attention as their good electrical conductivity and high lithium storage capacity. In this work, a simple and scalable approach was employed to synthesize CoSe nanoparticles confined in bifunctional N-doped carbon framework/carbon layer (CoSe/NC/C). Specifically, pyrolysis of cobalt phthalocyanine (CoPc)/Selenium mixtures was accompanied by Ethanol Steam Reforming (ESR) simultaneously, which could bring in double carbon network and restrict the growth of CoSe grains effectively to achieve more stable structure and fast ion/electron transfer within CoSe electrode. As a result, CoSe/NC/C composite delivers a superior discharge capacity of 531 mA h g-1 after 400 cycles at 1 A g-1 at room temperature and a remarkable cycling stability (458 mA h g-1 after 100 cycles at 1 A g-1) at elevated temperature (55 ℃). This excellent electrochemical performance may be attributed to the following factors. (a) The bifunctional carbon architecture can not only endow the composites with superior conductivity and enhanced structure stability, but also facilitate the uniform distribution of nano-sized CoSe. (b) The effective catalytic activity is inspired by the synergistic effect between CoSe nanoparticles and bifunctional carbon, which is supposed to contribute significant capacity and manifest distinct pseudocapacitive behavior, especially at high current density.

Sunlight-induced uranium extraction with triazine-based carbon nitride as both photocatalyst and adsorbent

Extracting uranium from high salinity seawater at ultralow concentrations would beneficially contribute to the sustainable utilization of nuclear energy, but it poses a significant challenge. Here we report a sunlight-driven photocatalysis-assisted extraction (SUPER) method by utilizing a bifunctional carbon nitride material, CN550, which has shown about a tenfold improvement in both adsorption capacity and photocatalytic activity compared to g-C3N4. Uranyl ions could be captured on the surface of CN550, and then deposited as metastudtite nanoparticles with light illumination. Compared with the pure physicochemical adsorption (PA) method, a tenfold higher uranium extraction capacity, up to 1556 mg g−1, has been attained. Additionally, a 25 times improvement of the partition coefficient (PC), from 0.312 to 7.778 L g−1, has also been achieved. In spiked real seawater, the extraction capacity can still achieve more than 1000 mg g−1, and the SUPER method has been found to work under natural sunlight illumination as well.

Oxygen assisted butanol conversion on bifunctional carbon nanotube catalysts: Activity of oxygen functionalities

Catalytic conversion of n-butanol to high-value-added product is considered as a highly important route towards biomass derived fine chemicals. The present work reports the applications of non-metallic multi-walled carbon nanotube (CNT) as bifunctional catalysts for oxygen assisted n-butanol conversion reactions. Oxidative dehydrogenation (ODH) and dehydration of n-butanol on CNT yielded aldehyde and alkene compounds via redox and acid catalytic routes, respectively. CNT exhibited high activity (over 50% n-butanol conversion) and stability (over 120 h) under gentle reaction conditions (<330 °C), which are competitive to conventional metal-based catalysts. Carboxylic acid groups were identified as catalytic active sites for dehydration reactions via linking the reactivity (kinetic parameters) with the surface composition and structural information of CNT catalysts. The redox activity could be related to ketonic carbonyl groups, and interestingly the intrinsic ODH catalytic activity is also influenced by degree of graphitization for CNT materials.

Bifunctional carbon monofluoride (CFx) coating on a separator for lithium-metal batteries with enhanced cycling stability

Herein, we suggest a new way to improve the cycling stability of the lithium-metal battery by using a separator coated by carbon monofluoride (CFx). CFx has been used as a cathode material for a lithium primary battery and is converted to LiF and carbon during the discharge process. The CFx-coated separator with 5 μm thickness is obtained by casting a CFx-containing slurry on a bare polyethylene separator and the CFx-coated separator is characterized in a LiCoO2 (LCO) // Li cell. The CFx-coated separator enables a better cycling stability up to 200 cycles than the bare separator due to its dual functions: 1) capturing cobalt ions dissolved from the LCO cathode and 2) formation of a thin and stable SEI layer containing LiF on the lithium metal anode. Employment of the CFx-coated separator also leads to much suppressed dendritic growth of lithium and stable interfacial resistance during the cycle.

Bifunctional Carbon Dots-Magnetic and Fluorescent Hybrid Nanoparticles for Diagnostic Applications.

There is a huge demand for materials capable of simple detection or separation after conjugation with specific biologic substances when applied as a diagnostic tools. Taking into account the photoluminescence properties of C-dots and the highly magnetic properties of Fe(0), a new hybrid composite of these components was synthesized via ultrasound irradiation. The material was fully characterized by various physicochemical techniques. The main goal of the current study was to obtain a highly magnetic and intense fluorescent hybrid material. The goal was achieved. In addition, magnetic particles tended to agglomerate. The new hybrid can be suspended in ethanol, which is an additional feature of the current research. The dispersion of the hybrid nanoparticles in ethanol was achieved by utilizing the interaction of iron particles with C-dots which were decorated with functional groups on their surface. The newly formed hybrid material has potential applications in diagnostic by conjugating with specific antibodies or with any other biologic compounds. Such application may be useful in detection of various diseases such as: cancer, tuberculosis, etc.

Electrochemistry of bi-redox ionic liquid from solution to bi-functional carbon surface

In this work, bi-redox molecule based ionic liquid was synthesized. Ferrocene donor group and anthraquinone acceptor group were linked to imidazolium cation. Next, the electrochemistry of the as synthesized molecule was investigated demonstrating the presence of two reversible redox systems. Furthermore, the diffusion coefficient and electron transfer rate constant were measured using the ferrocene oxidation and the anthraquinone reduction. Besides that, the bi-redox molecule was immobilized onto carbon electrode using two steps procedure based on the oxidative grafting of primary layer bearing diazonium head group followed by Gomberg-Bachmann coupling surface reaction. The surface characterization confirms the attachment of the imidazolium bi-redox molecule as well as the presence of the labile anion within the layer. Interestingly, the electrochemical investigations confirm the bi-redox grafting with an equi-distribution of the electron donor and acceptor within the attached layer. Finally, the attached layer exhibits an enhancement of double-layer capacitance which is correlated to the increase of the charge density and ionic property of the layer.

Investigating carbon metabolisms in the marine subsurface environment of the Juan de Fuca Ridge Flank

Microorganisms are the most diverse and abundant life on earth. They are responsible for recycling the elements of our planet and keeping our world habitable. Despite their importance, genome‐based analyses estimate that 90% of the microorganisms on our planet have not been cultured for laboratory investigations. The crustal biosphere of the Juan de Fuca Ridge Flank is a warm, subsurface environment, which has been shown to contain many uncultured organisms. Some of these uncultured groups harbor functional genes of evolutionary and biogeochemical significance, suggesting that further study will increase our knowledge of microbial survival on early Earth, as well as in this hydrothermal, nutrient‐limited crustal environment. In previous work the recovery of mono‐ and bifunctional carbon monoxide dehydrogenase genes suggested that carboxydotrophy may be a viable lifestyle in this environment. In May of 2019, the RV Atlantis traveled to the Juan de Fuca Ridge Flank to test this hypothesis. Equipped with custom fluid samplers the ROV Jason‐II was used to collect pristine crustal fluids from subsurface borehole observatories for chemical analyses and microbial culturing efforts. Our main objective was to measure potential carbon substrates, including carbon monoxide and methane, and to cultivate unique organisms from this environment to better understand carbon‐related metabolisms in this important but understudied aquifer.