Nitrogen Co-doped Carbon Research Articles

KOH activated nitrogen and oxygen co-doped tubular carbon clusters as anode material for boosted potassium-ion storage capability

Carbon nanomaterials have become a promising anode material for potassium-ion batteries (KIBs) due to their abundant resources, low cost, and excellent conductivity. However, among carbon materials, the sluggish reaction kinetics and inferior cycle life severely restrict their commercial development as KIBs anodes. It is still a huge challenge to develop carbon materials with various structural advantages and ideal electrochemical properties. Therefore, it is imperative to find a carbon material with heteroatom doping and suitable nanostructure to achieve excellent electrochemical performance. Benefiting from a Na2SO4 template-assisted method and KOH activation process, the KOH activated nitrogen and oxygen co-doped tubular carbon (KNOCTC) material with a porous structure exhibits an impressive reversible capacity of 343 mAh g−1 at 50 mA g−1 and an improved cyclability of 137 mAh g−1 at 2 A g−1 after 3000 cycles with almost no capacity decay. The kinetic analysis indicates that the storage mechanism in KNOCTC is attributed to the pseudocapacitive process during cycling. Furthermore, the new synthesis route of KNOCTC provides a new opportunity to explore carbon-based potassium storage anode materials with high capacity and cycling performance.

Nanocomposite of Ag nanoparticles and deep eutectic solvent-derived carbon dots with oxidase mimicking activity as synergistic bactericidal agent.

A new type of nitrogen and chloride co-doped carbon dots (N/Cl-CDs) based on choline chloride-urea-glycine ternary deep eutectic solvents (DESs) was synthesized using a one-step hydrothermal method. The prepared N/Cl-CDs exhibited oxidase-like activity and excellent antibacterial activity against Escherichia coli, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). The addition of silver nanoparticles (Ag NPs) (i.e. N/Cl-CDs + Ag NPs) to the N/Cl-CDs also significantly enhanced the oxidase and antibacterial activities. The nanocomposite (1·8 mg ml-1 ) completely inactivated 105 CFU per ml of MRSA in 90 min. E.coli and S. aureus were labelled with the N/Cl-CDs, enabling multicolour fluorescence imaging at different excitation wavelengths. The nanocomposites have high antibacterial efficiency as a new bactericidal agent, as well as application potential with good biocompatibility and low toxicity.

A two-dimensional G-CoP/N,P-co-doped carbon nanowire electrode for the simultaneous determination of hydroquinone and catechol in domestic wastewater

Hydroquinone (HQ) and catechol (CC) are important chemical raw materials in the modern industry, unfortunately, which are also high toxic phenolic pollutants. So how to achieve highly sensitive and selective determination HQ and CC is the challenge we face. In the present work, we report a facile strategy to obtain nitrogen and phosphorous co-doped glucose-derived carbon coated CoP nanowires (G-CoP/N,P–C NWs), in which nitrilotriacetic acid (NTA) was as the chelating reagent, glucose was as carbon source, and the precursors were subsequently experienced carbonization and phosphorization process. G-CoP/N,P–C NWs can shorten the distance of the electron transport and expand the reaction area, showing the intriguing electronic conductivity and electrocatalytic abilities. An electrochemical phenolic sensor based on G-CoP/N,P–C NWs is fabricated. The as-prepared sensor showcases the good sensing performance for HQ and CC with comparative linearity ranges of 0.8–900 μM (HQ) and 0.6–800 μM (CC), low limits of detections (LODs) of 0.18 μM (S/N = 3) and 0.12 μM (S/N = 3) for HQ and CC, respectively. Notably, it also displays excellent practical application for the recognition of HQ and CC in the rain water, the tap water, the domestic wastewater and the lake water, which may be a promising candidate in environmental water monitoring and drinking water safety.

Nitrogen and phosphorus co-doped carbon dots as an effective fluorescence probe for the detection of doxorubicin and cell imaging

Nitrogen and phosphorus co-doped carbon dots (NPCDs) with bright blue fluorescence were established by a hydrothermal method using alanine and diammonium phosphate as raw materials. The NPCDs were characterized by transmitted electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometry, ultraviolet–visible absorption (UV–vis), and fluorescence spectroscopy to investigate the morphology, elemental composition, and optical properties. The NPCDs had good water solubility, high dispersibility with an average diameter of only 2.77 nm, and satisfactory optical properties with a fluorescence quantum yield of 17.2%. The NPCDs were employed for the detection of doxorubicin (DOX). A good linear response of the NPCDs in the range 0.5–6.5 μM was obtained for DOX with a detection limit of 12 nM. The NPCDs were also applied to the analysis of real samples, urine and serum, with a recovery of 92.0–109.3%. The low cytotoxicity and good biocompatibility of the NPCDs were indicated by an MTT assay and cell imaging of HeLa cells. Compared with other detection systems, using NPCDs for DOX detection was a facile and efficient method with good selectivity and sensitivity.

High Quantum Yield Boron and Nitrogen Codoped Carbon Quantum Dots with Red/Purple Emissions for Ratiometric Fluorescent IO4– Sensing and Cell Imaging

A facile and cost-effective hydrothermal method was developed for the preparation of boron and nitrogen codoped carbon quantum dots (B,N-CQDs) from 3-carboxyphenylboronic acid and o-phenylenediamine. The synthesized B,N-CQDs exhibit excellent properties such as excellent water solubility, strong fluorescence, good dispersion, and desirable stability. The average particle size of B,N-CQDs is 2.82 nm, and the absolute fluorescence quantum yield is 86.58%. The excitation wavelength of B,N-CQDs is 300 nm. Emission bands of B,N-CQDs appeared at 356 and 700 nm. Periodate (IO4–) quenches B,N-CQDs emissions through chelation reaction. The ratio of F356/F700 has a good linear relationship with the concentration of IO4– in the range of 0.01–40 μmol/L with the detection limit of 0.003 μmol/L. This method has the advantages of a low detection limit, high sensitivity, wide linear range, good selectivity, simplicity, and rapidness. It can be used as a ratiometric fluorescent probe for the detection of IO4–, and it was successfully applied in the analysis of IO4– in water. The cytotoxicity and biocompatibility of B,N-CQDs were evaluated and successfully applied in cell imaging.

A Co-Doped Carbon Dot/Silver Nanoparticle Nanocomposite-Based Fluorescence Sensor for Metformin Hydrochloride Detection.

In this study, a fluorescence sensor based on nitrogen and phosphorus co-doped carbon dot/silver nanoparticle (NPCD/AgNP) nanocomposites was developed for metformin hydrochloride (MFH) detection. We first utilized the reducing nature of the NPCDs to prepare AgNPs from Ag+ and subsequently prepare NPCD/AgNP nanocomposites. The nanocomposite material was characterized by various methods, including electron microscopic methods (SEM and TEM), spectroscopic methods (UV-Vis, PL, FTIR, and XPS spectroscopy), light scattering (ELS), and XRD. Further, we utilized the enhanced fluorescence of the NPCDs as well as the overlap between the fluorescence emission spectrum of the NPCDs and the absorption spectrum of the AgNPs to use the NPCD/AgNP nanocomposites as an effective inner filter effect (IFE) pair for sensing MFH. The IFE between NPCDs and AgNPs in the nanocomposite material resulted in a significant quenching of the fluorescence intensity of the nanocomposites compared to that of the pure NPCDs. However, the fluorescence was recovered when MFH was introduced into the nanocomposite solution. The fluorescence intensity of the nanocomposites increased linearly as the MFH concentration increased from 2 to 100 µg/L. This detection method showed good sensitivity compared to other methods. It also showed high selectivity and high sensing potential for MFH in human serum and yielded acceptable results.

Activity descriptor of Ni,N-Codoped carbon electrocatalyst in CO2 electroreduction reaction

• Well-defined Ni,N-C catalysts with finely tunable N species were developed. • The correlation between the content of N specie and CO 2 RR activity was built. • The ratio of Ni-N specie can be used as an activity descriptor of Ni,N-C catalysts. • The universality of activity descriptor for Ni,N-C catalysts was confirmed. Nickel, nitrogen-codoped carbon materials (Ni,N-C) are flourishing as high-efficiency electrocatalysts for CO 2 electroreduction reaction (CO 2 RR). Nevertheless, the preparation of Ni,N-C electrocatalysts with high performance towards CO 2 RR is still blind, without any guidelines, due to the lack of defined and available activity descriptor. Herein, we explored the correlation between the ratio of N species and CO 2 RR activity with taking a series of well-defined Ni,N-C materials as representative electrocatalysts. By smartly utilizing the ratio of Ni-N specie as an activity descriptor, the correlation between the ratio of N specie (Ni-N) and CO partial current density over all samples presents a well volcanic trend. At the optimal ratio of Ni-N specie, a high CO Faradaic efficiency (FE) of 94.8 % can be achieved with a good stability for 29 h. More significantly, the activity range for a library of Ni,N-C electrocatalysts for CO 2 RR is distinctly divided according to the activity descriptor.

New insights into N, S doped carbon from conjugated polymers for efficient persulfate activation: Role of hydrogel beads in enhancement of stability

One-pot design of heteroatoms doped carbocatalysts for remediation of wastewater via persulfate (PS) activation is strongly desirable. Herein, a novel nitrogen and sulfur doped and co-doped carbons with controllable N, S doping is rationally prepared using pyrolysis strategy from polypyrrole-polythiophene polymers and copolymer. The N, S co-doped carbon (NS-C) show highly catalytic oxidation compared by N doped carbon (N-C) and S doped carbon (S-C) due to the synergistic effect between N and S dopants. It’s supposed that N and S doping can effectively create highly and main active sites to the electron transfer via PS activation, which could generate reactive oxygen species (ROS). Structure-dependent activity during activation of PS was confirmed by quenching experiments and electron paramagnetic resonance (EPR) analysis, prove that the non-radical species (1O2) is the main ROS generated. To improve the carbocatalyst separation and stability, the hydrogel beads-based alginate NS-C@Alginate were easily prepared. The catalytic efficiency rate by using the real water matrix shows that the NS-C/PS synergic system non-radical-led pathway exhibited a high ability to remediation of surrounding inorganic or organic compounds. This approach provides an innovative method for production and proves an efficient and environmentally benign carbocatalyst to PS activation for practical applications.

Quick and hassle-free smartphone's RGB-based color to photocatalytic degradation rate assessment of malachite green dye in water by fluorescent Zr-N-S co-doped carbon dots.

Sunlight active blue emissive zirconium, nitrogen, and sulfur co-doped carbon dots (Zr-N-S-CDs) have been synthesized by microwave-induced pyrolysis for achieving efficient photocatalytic degradation of pollutant malachite green dye (MG) in water. Surface morphology studies using high-resolution transmission electron microscopy confirmed the formation of spherical-shaped CDs with an absorbance peak at 350nm and emission peak at 437nm in UV-vis and fluorescence spectroscopy, respectively. Surface functional groups, elemental composition, and metal/non-metal co-doping were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. To understand the photocatalytic performance of Zr-N-S-CDs, various parameters, such as the source of energy, concentration of dye, catalyst dosage, and change in pH, were investigated. MG dye (20ppm) at a pH 7 with 0.5mg/mL of Zr-N-S-CDs could be photodegraded efficiently in 90min under sunlight (99%) compared to dark and artificial light conditions. Moreover, real-time analysis of degradation rate could be conveniently calculated by integrating the colorimetric responses of MG dye with RGB values obtained by the "Color Picker" app of a smartphone. The degradation rate obtained using a smartphone (97.89%) was found to be in agreement with the UV-vis spectroscopy (99%), thus, providing a new, handy, and instrument-free route for speedy and quantitative estimation of the degradation of hazardous MG dye by Zr-N-S-CDs.

Tuning the Sensing Properties of N and S Co-Doped Carbon Dots for Colorimetric Detection of Copper and Cobalt in Water.

In this study, nitrogen and sulfur co-doped carbon dots (NS-CDs) were investigated for the detection of heavy metals in water through absorption-based colorimetric response. NS-CDs were synthesized by a simple one-pot hydrothermal method and characterized by TEM, STEM-coupled with energy dispersive X-ray analysis, NMR, and IR spectroscopy. Addition of Cu(II) ions to NS-CD aqueous solutions gave origin to a distinct absorption band at 660 nm which was attributed to the formation of cuprammonium complexes through coordination with amino functional groups of NS-CDs. Absorbance increased linearly with Cu(II) concentration in the range 1–100 µM and enabled a limit of detection of 200 nM. No response was observed with the other tested metals, including Fe(III) which, however, appreciably decreased sensitivity to copper. Increase of pH of the NS-CD solution up to 9.5 greatly reduced this interference effect and enhanced the response to Cu(II), thus confirming the different nature of the two interactions. In addition, a concurrent response to Co(II) appeared in a different spectral region, thus suggesting the possibility of dual-species multiple sensitivity. The present method neither requires any other reagents nor any previous assay treatment and thus can be a promising candidate for low-cost monitoring of copper onsite and by unskilled personnel.

One-Pot Hydrothermal Synthesized Nitrogen and Sulfur Codoped Carbon Dots for Acid Corrosion Inhibition of Q235 Steel.

N and S codoped carbon dots having good water solubility have been successfully made by a novel hydrothermal method and characterized by FTIR, XPS, and TEM. The as-synthesized CDs were carbon particles rich in polar functional groups less than 10 nm in size. Electrochemical measurements, gravimetry, and surface analysis methods were utilized to examine the inhibition characteristics and adsorption mechanism of CDs on the carbon steel in acid pickling solutions. Electrochemical measurements verified that the CDs displayed adequate protection with high inhibition efficiency of 97.8%. The long-term weight-loss experiments up to 72 h further confirmed the excellent corrosion inhibition at room temperature and 313 K. The results presented are helpful for the formulation of more effective acid pickling corrosion inhibitors.

Nitrogen and sulfur co-doped carbon sub-micrometer sphere-based electrodes toward high-performance hybrid supercapacitors

The splendid electrochemical characteristics of electrode materials are crucial for achieving high-performance hybrid supercapacitors. In this study, homogeneously dispersed nitrogen and sulfur co-doped carbon (NSC) sub-micrometer spheres are synthesized under a facile polymerization reaction and subsequent carbonization treatment. The NSC sub-micrometer spheres deliver a commendable specific capacitance of 254.8F g−1 at 1 A g−1 along with fantastic cyclic capability benefiting from the rich heteroatoms doping and abundant sub-nanometer pores (<1 nm) on the surface. Besides, using the NSC sub-micrometer spheres as substrate, nickel phosphide (Ni2P) lamellas are in-situ grown on NSC by an effective strategy, which exhibit a decent capacity of 819 C g−1 at 1 A g−1 with 83.2% of capacity retention after 10,000 cycles at 10 A g−1. More importantly, the advanced hybrid supercapacitor fabricated by NSC anode and NSC/Ni2P cathode reveals a desirable energy density of 51.3 Wh kg−1 at 757 W kg−1 and maintains 41.9 Wh kg−1 at 18855 W kg−1 in 6 M KOH, demonstrating the great potential for energy storage applications.

Manganese Oxide/Iron Carbide Encapsulated in Nitrogen and Boron Codoped Carbon Nanowire Networks as Accelerated Alkaline Hydrogen Evolution and Oxygen Reduction Bifunctional Electrocatalysts.

Along with the widespread applications of various energy storage and conversion devices, the prices of precious metal platinum (Pt) and transition-metal cobalt/nickel keep continuously growing. In the future, designing high-efficiency nonprecious-metal catalysts based on low-cost iron (Fe) and manganese (Mn) metals for hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) is fairly critical for commercial applications of hydrogen fuel cells. In this study, for the first time, we design novel three-dimensional (3D) hybrid networks consisting of manganese oxide (MnO)-modified, iron carbide (Fe3C)-embedded, and boron (B)/nitrogen (N) codoped hierarchically porous carbon nanofibers (denoted FeMn@BNPCFs). After optimizing the pyrolysis temperatures, the optimal FeMn@BNPCFs-900 catalyst displays the best HER and ORR catalytic activities in an alkaline solution. As expected, the HER onset potential (Eonset) and the potential at a current density of -10 mA cm-2 for FeMn@BNPCFs-900 in 1.0 M KOH are just 36 and 194 mV more negative than the state-of-the-art 20 wt % Pt/C catalyst with more superior stability. In particular, the FeMn@BNPCFs-900 catalyst shows excellent ORR catalytic activity with a more positive Eonset (0.946 V vs RHE), a more positive half-wave potential (E1/2 = 0.868 V vs RHE), better long-term stability, and higher methanol tolerance surpassing the commercial 20 wt % Pt/C (Eonset = 0.943 V vs RHE, E1/2 = 0.854 V vs RHE) and most previously reported precious-metal-free catalysts in 0.1 M KOH. The synergistic effects of 3D hierarchically macro-/mesoporous architectures, advanced charge transport capacity, abundant carbon defects/edges, abundant B (2.3 atom %) and N (4.9 atom %) dopants, uniformly dispersed Fe3C@BNC NPs, and MnO nanocrystallines are responsible for the excellent HER/ORR catalytic activities of the FeMn@BNPCFs-900 catalyst.

Selective Aerobic Oxidation of Csp3-H Bonds Catalyzed by Yeast-Derived Nitrogen, Phosphorus, and Oxygen Codoped Carbon Materials.

Nitrogen, phosphorus, and oxygen codoped carbon catalysts were successfully synthesized using dried yeast powder as a pyrolysis precursor. The yeast-derived heteroatom-doped carbon (yeast@C) catalysts exhibited outstanding performance in the oxidation of Csp3-H bonds to ketones and esters, giving excellent product yields (of up to 98% yield) without organic solvents at low O2 pressure (0.1 MPa). The catalytic oxidation protocol exhibited a broad range of substrates (38 examples) with good functional group tolerance, excellent regioselectivity, and synthetic utility. The yeast-derived heteroatom-doped carbon catalysts showed good reusability and stability after recycling six times without any significant loss of activity. Experimental results and DFT calculations proved the important role of N-oxide (N+-O-) on the surface of yeast@C and a reasonable carbon radical mechanism.

Intensified coupled electrolysis of CO2 and brine over electrocatalysts with ordered mesoporous transport channels

The matched anodic and cathodic electrolysis can potentially increase the energy efficiency and produce value-added products simultaneously at both sides, and thus has attracted tremendous research interests. The success for a coupled electrolysis relies on not only the appropriate anodic and cathodic reaction pairs but also the suitable electrocatalysts that show high intrinsic activity, barrier-free ionic and electronic transport to the catalytic centers. Towards this goal, we showcased an efficient coupled electrolysis composed of the chloride oxidation reaction and the CO2 reduction reaction, in which the hexagonally ordered mesoporous electrocatalysts in terms of cobalt oxide and nickel, nitrogen co-doped carbons were used as anodic and cathodic electrocatalysts, respectively. Benefiting from the unique mesoporous structures, both the anodic and cathodic reactions exhibited prominent electrocatalytic performance in chloride salt electrolyte. Impressively, the coupled electrolysis showed a Faraday efficiency of 97% and 87% for CO and ClO−, respectively at cell voltage of ca. 2.5 V and current density of 20 mA cm−2. By doing so, a reduction in cell voltage by 1.8 V and an increase in energy efficiency by 40% were obtained as compared to the conventional system composed of cathodic CO2 reduction and anodic O2 evolution. This work not only highlights the importance of ordered mesoporous transport channels in accelerating the catalytic kinetics, but also showcases a high-performance coupled model for overall electrolysis.

Nitrogen and sulfur co-doped carbon dot-based ratiometric fluorescent probe for Zn2+ sensing and imaging in living cells.

Anear-infrared nitrogen and sulfur co-doped carbon dot (N,S-CD)-based ratiometric fluorescent probe is proposed that issynthesized via hydrothermal approach using glutathione and formamide as precursor for sensing and imaging of Zn2+. Theprepared N,S-CDs facilitate binding with Zn2+ owing to N and S atom doping. The ratio (I650/I680) of fluorescence intensity at 650nm and 680nm increased with the concentrations of Zn2+ when the excitation wavelength was 415nm. The linearity range was 0.01 to 1.0μM Zn2+with a detection limit of 5.0nMZn2+. The proposed probe was applied to label-free monitoring of Zn2+ in real samples and fluorescent imaging of Zn2+ in living cells, which confirmed its promising applications.

Orange/red dual-emissive boron- and nitrogen-codoped carbon dots for wash-free and selective staining of lipid droplets in live cells

Lipid droplet (LD) is an organelle that stores lipids and plays crucial roles in many metabolic processes and diseases. However, developing a method for long-term tracing of LDs and monitoring LD movement remains a challenge. Here, by using a solvent-free carbonization method, we prepare a kind of boron- and nitrogen-codoped carbon dots (BNCDs) from 3-aminophenylboronic acid. The as-synthesized BNCDs have an average size of ∼6.9 nm, long-wavelength fluorescence emission, and excitation wavelength-independent fluorescence emission, and can realize wash-free LD imaging without the introduction of LD-targeting ligands. Besides, the BNCDs have the characteristics of good biocompatibility, simple preparation, and low cost. More importantly, the BNCDs can effectively track the dynamic changes of LDs (including lipophagy) in live animal cells. This work shows that the developed BNCDs can be used as an ideal probe for nondestructively visualizing LDs, which may have implications for the future studies on LDs-related metabolism and diseases.

Nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons for supercapacitors

To achieve high-performance supercapacitors, nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons (CHC-SK) are successfully prepared by one-step carbonization. In the synthesis, two effective strategies of structure design and heteroatom doping are both used to increase capacitance of carbon materials. To control and design of structure, potassium citrate as a novel pore-former is introduced into chitosan hydrogel systems. It plays three roles in pore formation and thereby can be effective to optimize structure and improve surface area of CHC-SK. In addition, thiourea as binary doping of nitrogen and sulfur can effectively maximize the pseudocapacitance of CHC-SK. Therefore, CHC-SK with large surface area (1596.4 m2 g−1) and high heteroatom content (5.43% for nitrogen, 2.62% for sulfur) show excellent electrochemical performances. The specific capacitance of CHC-SK reaches up to 366.8 F g−1 at 0.5 A g−1. Even at the high current density of 10A g−1, its capacitance retention is 97.1% for 10,000 cycles. This simple strategy for the synthesis of nitrogen and sulfur co-doped porous chitosan hydrogel-derived carbons with high specific capacitance has promising applications in the future.

Fluorometric and electrochemical dual-mode detection of toxic flavonoid rutin based on new nitrogen and sulfur co-doped carbon dots: Enhanced selectivity based on masking the interfering flavonoids with BSA complexation

A simple, cost-effective, and convenient bimodal strategy for the detection of toxic flavonoid rutin was proposed. The strategy depends on fluorometric and electrochemical determination of rutin using new type of nitrogen and sulfur co-doped carbon dots (N, S@C-dots). The fluorescence detection based on quenching the emission of N, S@C-dots by rutin through inner-filter effect (IFE), while the electrochemical detection based on direct oxidation of rutin at glassy carbon electrode (GCE) modified with N, S@C-dots. Many factors affecting fluorometric and electrochemical measurements were optimized. The decrease of emission intensity and the increase of the electrochemical signal are linear over the concentration range of 0.02−92.3 μM and 0.2−130 × 10−8 M, respectively. The limits of detections (LODs) were found to be 8.0 nM and 0.8 nM for the fluorometric and electrochemical methods, respectively. Moreover, short response times (2.0 and 2.5 min) were achieved using the fluorometric and electrochemical methods, respectively. The selectivity of the fluorometric sensor towards rutin was enhanced; in the presence of other interfering flavonoids; by the addition of bovine serum albumin (BSA).

Microwave-assisted facile synthesis of N, P co-doped fluorescent carbon dot probe for the determination of nifedipine.

A simple and fast microwave synthesis method was applied for the preparation of several carbon dots (CDs) from various combinations of urea, phosphoric acid, and B-alanine as nitrogen, phosphorus, and carbon precursors. The maximum quantum yield (44%) was obtained for nitrogen and phosphorus co-doped carbon dots (N, P-CDs) prepared from urea, B-alanine, and phosphoric acid. Furthermore, N, P-CDs were exploited to synthesize a simple and sensitive fluorometric probe to determine nifedipine (NFD). We determined that the analytical response of the designed sensor could be affected by the kind of dopant and synthesis precursors. It is worth mentioning that the fluorescence intensity of N, P-CDs was weakened by NFD, and no fluorescence quenching was observed for other prepared CDs. The NFD-developed sensor demonstrated a linear response range of 3.3 × 10-8-3.2 × 10-5mol/L, with the detection limit of 1.0 × 10-8mol/L. The sensor was successfully applied to measure NFD in human biological fluids.