Phosphorus Co-doped Carbon Research Articles

Nitrogen and phosphorus co-doped carbon networks derived from shrimp shells as an efficient oxygen reduction catalyst for microbial fuel cells

The waste shrimp shells (SS) were used as both carbon and nitrogen sources to directly synthesize N and P co-doped carbon networks with abundant mesopores and high specific surface area by simple acid pretreatment and carbonization. Using exogenous phosphorus as dopant, the prepared catalyst (PA-SS 900) favorably possessed a high oxygen reduction reaction (ORR) activity regarding half-wave potential (0.82 V) and limiting current (4.47 mA cm−2), which approached those of commercial 20 wt% Pt/C. For practical application in microbial fuel cell (MFC), the N, P co-doped PA-SS 900 achieved a maximum power density (MPD) of 802 mW m−2 and an open circuit voltage (OCV) of 653 mV, which also were close to that (892 mW m−2 and 752 mV) based on 20% Pt/C as cathode catalyst. Remarkably, the synthetic catalyst had a better long-term stability than that of 20% Pt/C in alkaline medium. These results demonstrated that N, P co-doped PA-SS 900 was an accessible and efficient ORR catalyst in air-cathode MFC for relatively desirable energy generation and wastewater treatment. Further, the direct utilization of waste shrimp shells replacing chitin or chitosan in energy conversion is worthy of in-depth study due to the advantages of simple process, environmental friendliness and availability.

Nitrogen and phosphorus co-doped 3D hierarchical porous carbon network with highly-reversible performance in sodium storage

In this paper, synthesis of nitrogen and phosphorus co-doped 3D hierarchical porous carbon network (NP–CN) with superior electrochemical performance in sodium-ion battery anode material was reported. In terms of structure, 3D network structure can fully alleviate the stress generated during charging and discharging, while hierarchical porous structure provides more electron and ion transmission channels, which facilitates rapid transfer of charge. Meanwhile, doping of nitrogen and phosphorus can increase defect sites of material to promote sodium ion adsorption. In addition, nitrogen can enhance conductivity of material and phosphorus can be inserted into carbon lattice to enlarge interlayer spacing, beneficial to the intercalation and deintercalation of sodium ions. Based on above advantages, NP-CN possesses 315 mAh g−1 at 100 mA g−1 after 200cycles in sodium-ion battery. Furthermore, the method is simple and raw material is easy to obtain, making NP-CN have better practical value.

Manipulation of interlayer spacing and surface charge of carbon nanosheets for robust lithium/sodium storage

The sluggish kinetics in anode materials severely prevents the practical use of lithium/sodium-ion batteries in many current and emerging applications. To overcome this bottleneck, we report a facile and scalable strategy to construct nitrogen and phosphorus co-doped carbon nanosheets with abundant electron-rich regions rendering a strong cation attraction and expanded interlayer spacing for fast lithium/sodium diffusion, which allows excellent rate capable anodes for lithium/sodium-ion batteries. Specifically, the as-prepared nanosheets afford outstanding pseudocapacitive behavior with superior rate capacities of 379 and 140 mA h g−1 at a high current density of 5.0 A g−1 for lithium and sodium storage, respectively, while the calendar life can be as long as thousands of cycles. The extraordinary rate capability is further demonstrated through combined use of quantitative kinetics analysis, galvanostatic intermittent titration technique measurements and theoretical simulation. Considering the extraordinary electrochemical performance and comprehensive analysis of pseudocapacitive lithium/sodium storage mechanism, this work holds great potential to serve as a fundamental reference for exploring robust pseudocapacitive electrode materials.

Preparation of Phosphorus and Oxygen Co-Doped With Graphite Carbon Nitride and Its Application in Photodegradation of Methylene Blue

In this study, phosphorus and oxygen co-doped graphite carbon nitride has been successfully prepared by simple thermal copolymerization. The as-prepared materials were characterized by SEM, XRD, XPS and UV-vis-DRS. The results showed that phosphorus and oxygen were successfully doped on the structure of graphite carbon nitride. Photocatalytic degradation of MB in solution by the catalyst has been studied, POCN-1 has the best photocatalytic activity among of the as prepared materials, photocatalytic degradation rate of MB is 10.6 times higher than that of g-C3N4. The main reason for its enhanced photocatalytic performance is that the co-doped of phosphorus and oxygen elements would change the electronic structure of g-C3N4, reduce the forbidden band width of the photocatalyst. At the same time, can extend the absorption boundary of visible light.

Efficient room temperature phosphorescence carbon dots: Information encryption and dual-channel pH sensing

Chemical doping with nitrogen, phosphorus or halogens can effectively favor the room temperature phosphorescence (RTP) appearing of carbon dots (CDs) through facilitating their intersystem crossing (ISC) process. Here we raised a facile microwave strategy to synthesize nitrogen and phosphorus co-doped carbon dots (P-CDs), while triethanolamine served as the carbon source with phosphoric acid being the dopant. Meanwhile, the P-CDs showed both the bright-blue fluorescent emission and the green-RTP emission. Additionally, the filter paper functioned as the matrix to stabilize the triplet excitons of P-CDs, thus achieving their RTP emission by suppressing the non-radiative transitions. Significantly, an innovative painting technology of employing P-CDs as RTP-ink has been developed toward the confidential information encryption. Moreover, we applied the proposed P-CDs to respectively assay pH ranging from 9.15 to 13.55 and 2.29 to 13.55 by virtue of their pH-responsible fluorescence and RTP. Again, we further explored the fluorescent and phosphorescent sensing mechanism of P-CDs by the deprotonation of P–O bonds and the precipitation of P-CDs.

Bacteria-Derived Biological Carbon Building Robust Li–S Batteries

Lithium sulfur (Li-S) batteries are attracting increasing interest for high-density energy storage. However, the practical application is limited by the rapid capacity fading over repeated charge/discharge cycles which is largely attributed to the formation and shuttling of soluble polysulfide species. To address these issues, we develop a hierarchical structure composite with triple protection strategy via graphene, organic conductor PEDOT, and nitrogen and phosphorus codoped biological carbon to encapsulate sulfur species (GOC@NPBCS). This unique hierarchical structure can effectively immobilize the sulfur species while at the same time improve the electrical conductivity and ensure efficient lithium ion transport to enable excellent Li-S battery performance. In particular, the biological carbon derived from natural bacteria features inherent nitrogen and phosphorus codoping with a strong absorption to lithium polysulfides, which can greatly suppress the dissolution and shuttling of polysulfides that are responsible for rapid capacity fading. With these synergistic effects, the GOC@NPBCS cathode exhibits exceptionally stable cycling stability (an ultralow capacity fading rate of 0.045% per cycle during 1000 cycles at the current rate of 5 C), high specific capacity (1193.8 mAh g-1 at 0.5 C based on sulfur weight), and excellent rate capability.

An efficient metal-free phosphorus and oxygen co-doped g-C3N4 photocatalyst with enhanced visible light photocatalytic activity for the degradation of fluoroquinolone antibiotics

Non-metal doping has been frequently used in g-C3N4 (CN) as a feasible and economical technique for maintaining its metal-free properties, while improving its photocatalytic performance. In this study, a novel phosphorus and oxygen co-doped graphitic carbon nitride (POCN) was successfully synthesized through a one-step thermal polymerization method and exhibited remarkable photocatalytic activity for the photocatalytic degradation of fluoroquinolones (FQs). The degradation rate of enrofloxacin (ENFX) was 6.2 times higher than that of CN. Based on the results of X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), P atoms replaced the corner and bay carbon sites, whereas O atoms replaced the nitrogen sites in the g-C3N4 framework. The improvement of the photocatalytic effect of POCN0.01 was attributed to its narrow bandgap, effective charge separation and enhanced specific surface area. This is the first report to describe the use of phosphorus doping to promote the generation of reactive oxygen species (ROS). ROS scavenging tests revealed that O2− was the primary active species during the degradation of ENFX. Furthermore, pathways for the degradation of ENFX were proposed via the detection of intermediate products via HRAM LC–MS/MS and the prediction of active sites using the Fukui function.

Polyaniline-manganese dioxide-carbon nanofiber ternary composites with enhanced electrochemical performance for supercapacitors

A new ternary composite of polyaniline/manganese dioxide/nitrogen, phosphorus co-doped carbon nanofiber (PANI/MnO2/NPCNF) has been synthesized by electrospinning technology and chemical oxidative reactions. The results show that MnO2 and PANI layers are uniformly coated on the surface of N, P co-doped CNF. The optimal ternary nanocomposite shows excellent electrochemical performance (587.3Fg−1 at 0.5Ag−1, ~63% capacitance retention from 0.5Ag−1 to 20Ag−1 and capacitance retention is ~84% after 1000cycles at 10Ag−1). That could be attributed to the synergistic effects contributed from individual components. The N, P co-doped CNF acts as carbon scaffold to facilitate the electron transform and improves the poor electrical conductivity of MnO2. The outer PANI layer could achieve high pseudo-capacitance, protect the MnO2 layer from reductive-dissolving and further heighten its electrochemical utilization.

Nitrogen, phosphorus co-doped mesoporous carbon materials as efficient catalysts for oxygen reduction reaction

Carbon, phosphorus or nitrogen-doped carbon and nitrogen, and phosphorus co-doped carbon materials were successfully synthesized. The scanning electron microscopy and transmission electron microscope indicated that the samples exhibited three-dimensional layered structure. While the X-ray diffraction and Raman results suggested that the samples were typical carbon materials with high purity, besides, the nitrogen adsorption-desorption isotherm results showed that the nitrogen, phosphorus co-doped carbon material had the highest specific surface area of 2346.2 m2 g−1 with uniform mesoporous (3.8 nm) and considerable pore volume (0.69 cm3 g−1). The cyclic voltammetry, electrochemical impedance spectra, liner sweep voltammetry, and chronoamperometry were tested in oxygen-saturated 0.1 M KOH solution. The electrochemical tests suggested that the nitrogen, phosphorus co-doped carbon material had a positive onset potential (0.92 V), half-wave potential (0.81 V), low resistance (73 Ω), and low Tafel slope (70 mV/decade) at low current region. More importantly, the oxygen reduction reaction was a 4-electron pathway with excellent methanol tolerance.

In situ preparation of P, O co-doped carbon spheres for high-energy density supercapacitor

Phosphorus and oxygen co-doped carbon spheres with formaldehyde and resorcinol as precursor were successfully prepared by using phosphoric acid solution as phosphorus source and catalyst. When the pH value of applied phosphoric acid solution is set at 1.38, the spherical carbon materials can be obtained. The corresponding specific surface area can reach 739.48 m2 g−1, and the phosphorus amount can be 0.44 at.%. By contrast, bulk carbon materials were produced when the pH value increased to 3.72. The corresponding specific surface area decreased to 444.3 m2 g−1, and the phosphorus amount declined to 0.10 at.%. It is demonstrated that spherical carbon materials exhibit superior electrochemical performance. The specific capacitance can reach 297.5 F g−1 at the scan rate of 1 mV s−1. Symmetric supercapacitors were constructed with KOH and Na2SO4 as electrolytes, respectively. The specific capacitance can reach 186.8 F g−1 at the current density of 0.1 A g−1 when KOH is used as electrolyte and its energy density can reach up to 50.86 Wh kg−1. However, the stability of the device is relatively poor. In contrast, when sodium sulfate is used as the electrolyte, after 5000 cycles of constant current charge and discharge, the capacity is still 84.09% remaining, exhibiting excellent cycle stability. In addition, the energy density of the device can reach 39.4 Wh kg−1. Even when the power density is 4000 W kg−1, the energy density can still reach 10 Wh kg−1. The obtained materials show great potential for practical application.

Co-based MOF-derived Co/CoN/Co2P ternary composite embedded in N- and P-doped carbon as bifunctional nanocatalysts for efficient overall water splitting

Abstract In this work, we developed ternary metallic cobalt-cobalt nitride-dicobalt phosphide composite embedded in nitrogen and phosphorus co-doped carbon (Co/CoN/Co2P-NPC) as bifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The as-prepared Co/CoN/Co2P-NPC is achieved by simultaneous annealing and phosphating of a Co–N rich metal-organic frameworks (MOFs) precursor. Compare with the phosphorus-free Co/CoN embedded nitrogen-doped carbon electrocatalyst (Co/CoN-NC), the as-prepared Co/CoN/Co2P-NPC display superior HER and OER low overpotential of 99 mV and 272 mV at current density of 10 mA cm−2. When Co/CoN/Co2P-NPC electrocatalyst is use as bifunctional catalysts in overall alkaline water splitting, it exhibit excellent behaviour with 10 mA cm−2 current at overall cell potential of 1.60 V. The excellent performance of Co/CoN/Co2P-NPC electrocatalyst is attributed to the phosphating process that could further enhance synergistic effect, create stronger electronic interactions, and form efficient dual heteroatom doping to optimize the interfacial adhesion within the electrocatalyst. This present work will create more opportunities for the development of new, promising and more active sites electrocatalysts for alkaline electrolysis.

The excellent capacitive capability for N,P-doped carbon microsphere/reduced graphene oxide nanocomposites in H2SO4/KI redox electrolyte

In order to ameliorate the capacitance and energy density of supercapacitors in aqueous electrolytes, nitrogen- and phosphorus-codoped carbon microspheres/reduced graphene oxide nanocomposites are obtained by hydrothermal treatment of graphite oxide and N,P-doped carbon microsphere. The as-prepared nanocomposites display a high specific surface area of 604.3 m2 g−1 and hierarchical pore structure composed of micropores, mesopores, and macropores. N,P-codoped carbon microspheres/reduced graphene oxide are used as electrode materials in the redox electrolyte of H2SO4 and KI aqueous solution, exhibiting a excellent capacitance performance of up to ~ 654 F g−1 at 2 A g−1, corresponding to the energy density of 14.53 Wh kg−1 at power density of 402 W kg−1. Even at a high current of 20 A g−1, the electrode can keep a capacitance of 318 F g−1, showing an energy density of 7 Wh kg−1 at power density of 3984 W kg−1. This study indicates the potential of nitrogen- and phosphorus-codoped carbon microspheres/reduced graphene oxide in high energy density supercapacitor.

Hydrothermal synthesis of carbon dots codoped withnitrogen and phosphorusas a turn-on fluorescent probe for cadmium(II).

Nitrogen and phosphorus co-doped carbon dots (N,P-CDs) have been synthesized via hydrothermal method starting from o-phosphorylethanolamine and citric acid. The blue-green fluorescence of the N,P-CDs (with excitation/emission peaks at 325/435nm) isgradually enhanced on sequential addition of Cd(II) ions. This fluorometric assay works in the 0.5μM to 12.5μM Cd(II) concentration range and has a 0.16μM detection limit. The phenomenon may be attributed to chelation enhanced fluorescence that is induced by the formation of Cd(II)-N,P-CDs complex with functional groups present on the surface. The method has applied to the detection of Cd(II) in spiked serum and urine samples and gave satisfying results. Graphical abstract Schematic presentation of the synthesis of nitrogen and phosphorus co-doped carbon dots (N,P-CDs) and their application as a turn-on fluorescence probe for Cd(II) detection.

Ag3PO4 modified phosphorus and sulphur co-doped graphitic carbon nitride as a direct Z-scheme photocatalyst for 2, 4-dimethyl phenol degradation

Very recently, hybrid photocatalysts are gaining importance due to their unique and enhanced photocatalytic activity. In precedent study, we have successfully prepared Ag3PO4 (AP) and P and S co-doped g-C3N4 (PSGCN) based AP/PSGCN photocatalyst via facile deposition-precipitation method. The P and S co-doped g-C3N4 was prepared via thermal poly-condensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. The photocatalysts were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), X- ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The thickness of AP/PSGCN was less than 9.0 nm. The zeta potential and Tyndall effect experiments validated the formation of well dispersed suspension of AP/PSGCN in water. The co-doping resulted in lowering of optical band gap of g-C3N4. The Tyndall effect experiments ascertained the formation of well dispersed suspension of AP/PSGCN. The photoluminescence and electrochemical impedance analysis confirmed reduction in recombination of photogenerated electron and hole pairs. The photodegradation of 2,4-dimethyl phenol (DMP) followed pseudo first order kinetics. The enhanced photocatalysis was due to direct Z-scheme mechanism. Hydroxyl and superoxide radicals were the two main reactive species during DMP degradation. The COD, HPLC and LCMS investigations ascertained mineralization of DMP. AP/PSGCN displayed high stability and recycle efficiency significant for ten catalytic cycles.

Single-atomic-site cobalt stabilized on nitrogen and phosphorus co-doped carbon for selective oxidation of primary alcohols

Single-atomic-site Co stabilized on nitrogen and phosphorus co-doped carbon exhibits superior performance for the oxidation of substituted primary alcohols.

Multi-heteroatom doped graphene-like carbon nanospheres with 3D inverse opal structure: a promising bisphenol-A remediation material

Nitrogen, phosphorus and sulfur co-doped graphene-like carbon nanospheres with 3D inverse opal structure as a promising bisphenol-A remediation material.

Multi-shelled ZnO decorated with nitrogen and phosphorus co-doped carbon quantum dots: synthesis and enhanced photodegradation activity of methylene blue in aqueous solutions.

The presence of organic dyes in wastewater has posed a huge threat to aquatic life and human health. In this study, nitrogen and phosphorus co-doped carbon quantum dot (CQD)-decorated multi-shelled ZnO microsphere photocatalysts (NPCQD/ZnO) were obtained via a simple absorption process; ZnO was prepared by calcining carbon microspheres as the sacrificial template. The as-prepared NPCQD/ZnO showed an obvious multi-shelled structure with the nitrogen and phosphorus co-doped CQDs homogeneously attached onto the inner and outer shells of ZnO. According to the UV-Vis DRS results, all the co-doped, single-doped and undoped carbon quantum dots could enhance the efficiency of absorption of visible light and reduce the optical band gap. Furthermore, the PL characterization results showed that the NPCQD/ZnO composites had lowest fluorescence intensity because the decoration of ZnO with NPCQDs could effectively reduce the recombination rate of photogenerated electron–hole pairs in the ZnO semiconductor photocatalyst. Importantly, 2 g-NPCQD/ZnO composites exhibited higher photodegradation performance towards methylene blue (MB) than pure ZnO and even the newly reported series of ZnO catalysts under the same conditions. Moreover, the degradation obeyed the pseudo-first-order and Langmuir–Hinshelwood kinetics models with a reaction constant of 0.0725 min−1, which was 1.05 times that of pure ZnO (0.0353 min−1). The NPCQD/ZnO composites not only showed good photocatalytic performance, but also had excellent stability since the photocatalytic activity did not significantly decrease after five cycling tests. In addition, compared with single-doped and undoped carbon quantum dots, N and P co-doped carbon quantum dots have more significant efficiency for the modification of semiconductor photocatalysts. The present study shows that the CQD-decorated multi-shelled ZnO can be regarded as an excellent photocatalyst candidate in the field of water treatment. Moreover, this new concept is helpful in the controllable construction of other multi-shelled metal oxides decorated with co-doped carbon quantum dots with enhanced photocatalytic properties.

Three-dimensional nitrogen and phosphorus co-doped carbon quantum dots/reduced graphene oxide composite aerogels with a hierarchical porous structure as superior electrode materials for supercapacitors

A novel 3D N, P-CQDs/rGO composite aerogel with a hierarchical porous structure is prepared, and excellent supercapacitive properties are achieved.

An Ultrasensitive and Highly Selective Electrochemical Aptasensor for Environmental Endocrine Disrupter Bisphenol A Determination Using Gold Nanoparticles/Nitrogen, Sulfur, and Phosphorus Co-Doped Carbon Dots as Signal Enhancer and Its Electrochemical Kinetic Research

Electrochemistry will bring revolutionary detection methods for bisphenol A (BPA) which is a endocrine disrupter. Electrochemical aptasensor appears to be a promising approach to this end because of its brilliant specificity, high affinity, low cost and rapid response time. However, electrochemical aptasensor suffers from reducing signal when anti-BPA aptamers are modified on electrode surface. In response, we report an electrochemical aptasensor based on gold nanoparticles (AuNPs) and nitrogen, sulfur, and phosphorus co-doped carbon dots (N,S,P-CDs) modified glassy carbon electrode(GCE) for amplified signal detection of BPA. The thiol-gold (S-Au) bonds between the AuNPs and the thiol termini on anti-BPA aptamers anchor the anti-BPA aptamers to the GCE. N,S,P-CDs as electrode modifications are applied to expand the active area and enhance electron-transport ability. In this work, the presences of N,S,P-CDs and the AuNPs were assessed via Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD), etc. The sensing scheme and electrochemical response of the proposed sensor were investigated by chronocoulometry (CC), cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and differential pulse voltammetry (DPV). Meanwhile, we focused on discussing the kinetic parameters of [Fe(CN)6]3−/4− on the composite electrode that had reacted with BPA, such as active surface areas (A), surface concentration (Г0), the standard rate constant (k) and electron transfer coefficient (α). Aptasensor revealed a high sensitivity and had a linear electrochemical response to BPA in the concentration range of 0.01 μM–120 μM, with a low detection limit of 5.273 × 10−10 M. Moreover, the proposed aptasensor could be applied for the detection of BPA in real samples with great precision, high sensitivity, excellent selectivity, brilliant reproducibility and satisfactory results. Therefore, this convenient and sensitive aptasensor is proved to a promising and reliable tool for detecting BPA in food and environmental pollution.

Nitrogen and phosphorus co-doped carbon dots as a “turn-off-on” fluorescence probe for the detection of Hg2+ and GSH and cell imaging

Nitrogen and phosphorus co-doped carbon dots (NPCDs) were synthesized by a microwave method, using citric acid monohydrate and diammonium hydrogen phosphate as raw materials.