Phosphorus-doped Carbon Research Articles

Synergistic modulation of iron phosphide and phosphorus-doped carbon to boost ammonia electrosynthesis from nitrate

Synergistic modulation of iron phosphide and phosphorus-doped carbon to boost ammonia electrosynthesis from nitrate

Highly Porous Nitrogen and Phosphorus Dual-Doped Carbon with Increased Phosphorus Content As an Efficient Oxygen Reduction Electrocatalyst

Fuel cells and metal-air batteries have attracted the attention of many researchers because of their high power density and large energy density. Carbon materials are typically used as catalyst supports and conductive agents at the cathodes in fuel cells and metal-air batteries. However, pure carbon exhibits low electrocatalytic activity for the oxygen reduction reaction (ORR) at the cathodes. Single doping of heteroatoms, such as nitrogen and phosphorus, has been investigated as a simple method to improve the ORR activity of carbon materials. Moreover, compared with single doping, dual doping of nitrogen and phosphorus can further enhance the ORR performance due to the synergetic effect of the dopants [1]. Acetylene blacks (ABs) are readily available and widely used in industry for pigments, reinforcing rubber, and battery electrodes. However, the content of heteroatoms doped into AB by conventional heat treatment is low [2]. Recently, mechanochemical treatments have received increasing attention because they are more robust and simpler than conventional methods. Some studies have been conducted on solid-gas mechanochemical treatment under an air atmosphere as a nitrogen doping method for graphite and graphite-based materials [3]. In this study, nitrogen and phosphorus dual-doped carbon (NPC) was synthesized by a two-step method: solid-gas mechanochemical treatment using a planetary ball mill at a rotation speed of 600 rpm for 1 h to prepare nitrogen-doped carbon (NC), followed by heat treatment with ammonium dihydrogen phosphate (ADP) at 800 °C for 12 h to dope the NC with phosphorus. For comparison, phosphorus-doped carbon (PC) was synthesized by heat treatment of AB with ADP at 800 °C for 12 h.X-ray photoelectron spectroscopy was used to identify the doping states and concentrations of the samples. NPC has high concentrations of nitrogen (1.60 at%) and phosphorus (1.91 at%). In contrast, PC has a low phosphorus concentration (0.14 at%). Scanning electron microscopy revealed that mechanochemical treatment using a ball mill broke the particles and reduced their size from 35 nm in AB to approximately 10 nm in NC and NPC. The surface areas of NC and NPC significantly increased to 424 m2 g−1 and 540 m2 g−1, respectively, compared with that of AB (64.7 m2 g−1), mainly due to particle size reduction. Furthermore, NC and NPC exhibit high porosity with a maximum at 3.6 nm (Fig. 1a). The primary pores of NC and NPC constitute spaces between the particles. Electrochemical measurements were performed using a rotating disk electrode (RDE) in O2-saturated 1.0 M KOH. Linear sweep voltammetry curves of samples at an RDE rotation speed of 1600 rpm are shown in Fig. 1b. NC exhibits a much higher kinetic current density of 1.71 mA cm−2 at −0.15 V vs. Hg/HgO calculated from a mass transport correction of RDE than AB (0.04 mA cm−2), suggesting that the doped nitrogen and high porosity in NC significantly promote the ORR process. Furthermore, NPC shows 2.4 times higher kinetic current density of 4.14 mA cm−2 than NC, indicating that additional phosphorus doping into NC can enhance the ORR activity. Owing to the highly porous structure in NC, phosphorus atoms can be effectively doped into the carbon matrix during heat treatment, which may lead to the generation of abundant active sites for the ORR in NPC.

Synthesis of nanostructured cerium oxide-decorated phosphorus-doped carbon matrix electrodes for hybrid supercapacitors

Synthesis of nanostructured cerium oxide-decorated phosphorus-doped carbon matrix electrodes for hybrid supercapacitors

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Highly Porous Nitrogen and Phosphorus Dual-Doped Carbon with Increased Phosphorus Content As an Efficient Oxygen Reduction Electrocatalyst

Highly porous nitrogen and phosphorus dual-doped carbon (NPC) was synthesized using acetylene black as a carbon source in two steps: (1) solid–gas mechanochemical treatment to prepare nitrogen-doped carbon (NC), (2) heat treatment to dope the NC with phosphorus. X-ray photoelectron spectroscopy and N2 gas adsorption analysis revealed that the solid–gas mechanochemical treatment using a ball mill incorporated nitrogen atoms into the carbon network and increased the pore volume and surface area. Furthermore, the resulting NC exhibited enhanced reactivity with ammonium dihydrogen phosphate, which was used as a phosphorus source, upon heat treatment. The phosphorus content in NPC synthesized by two-step mechanochemical and heat treatments reached 1.91 at%, a 14-fold increase compared to that of phosphorus-doped carbon synthesized by heat treatment. The NPC exhibited higher electrocatalytic activity for the oxygen reduction reaction than NC, suggesting that the additional phosphorus doping into NC can improve its electrocatalytic performance.

Z-Scheme Heterojunction of Phosphorus-Doped Carbon Nitride/Titanium Dioxide: Photocatalytic Performance.

With increasingly serious environmental pollution problems, the development of efficient photocatalytic materials has become a hotspot in current research. This study focused on phosphorus-doped carbon nitride/titanium dioxide (PCT) Z-type heterojunctions, aiming to deeply investigate their photocatalytic degradation and photosensitive antimicrobial properties. A PCT Z-type heterojunction was successfully fabricated using melamine phosphate, cyanuric acid, and titanium dioxide. The structure, morphology, and optical properties of PCT Z-type heterojunctions were explored by FTIR, XRD, XPS, BET, SEM, UV-Vis DRS, TEM, EIS, and PL. A comprehensive and in-depth analysis of the structure, morphology, and optical properties of PCT Z-type heterojunctions was carried out. The photocatalytic degradation experiments revealed that PC3T Z-type heterojunctions exhibited an excellent degradation capability for methylene blue (MB) under visible light. The effect of PC3T on the adsorption-photocatalytic degradation of MB is more than 1.5 times that of a single titanium dioxide and P-doped carbon nitride. In the photosensitive antimicrobial performance study, PC3T reduced the survival rate of E. coli to 7%, after 120 min. Through free radical trapping experiments, it was shown that the hydroxyl radicals and superoxide radicals exerted an influence on the photocatalytic process. This study offers new ideas and approaches to address environmental pollution problems and holds significant theoretical and applied value.

P-doped carbon dot nano-probe for inner filter effect-based determination of sarecycline in pharmaceutical dosage form and human plasma.

Based on novel phosphorus-doped carbon dots (PCDs), a simple, quick, and accurate fluorescence probe for sarecycline (SAR) determination has been created. The PCDs were prepared in just five minutes using green, straightforward one-step microwave pyrolysis. To create the PCD probe, sodium phosphate monobasic was utilized as a phosphorus dopant and citric acid as a carbon supply. The proposed synthesis method was energy efficient and yielded CDs with a narrow particle size distribution. Based on inner-filter effect mechanism, the generated PCDs were used as nano-probe for SAR determination. The fluorescence quenching intensity showed a strong linear relationship with SAR concentration in the 3-90-μM range with a detection limit of 0.88 μM. Because there is no surface alteration of the CDs or creation of a covalent bond between SAR and PCDs, the developed approach is quick, easy, inexpensive, and requires less time. The new probe's enhanced sensitivity, broad linear range, and acceptable selectivity made it suitable for SAR measurement in pharmaceutical formulations and spiked human plasma. Most importantly, the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) assessments showed that the suggested method was environmentally friendly.

Metal-Free Carbon Co-Catalysts for Up-Conversion Photo-Induced Catalytic Cancer Therapy.

Near-infrared (NIR)-responsive metal-free carbon co-catalysts that convert glucose into H2O2 to generate reactive oxygen species (ROS) are developed from phosphorus-doped carbon nitride (P-C3N4) and graphene quantum dots (GQD) composites, for enhanced photocatalytic cancer therapy by light exposure in the targeted tumor microenvironment. Upon irradiation, the NIR light is converted by GQD with up-conversion function into visible light to excite P-C3N4 for photocatalytic conversion of glucose into H2O2, which subsequently decomposes into ROS. ROS thus generated exhibits an excellent anticancer efficacy for efficient cancer therapy with minimal side effects, as evidenced by both in vitro and in vivo studies. This study demonstrates, for the first time, a cancer therapeutic of GQD/P-C3N4 composite that utilizes a two-step cascade effect using initially NIR-triggered GQD nanoparticles to activate P-C3N4 to photocatalytically generate ROS for effective and targeted cancer therapy.

Increasing Graphene Selectivity for H2O2 Electro-Production Using Phosphorus Doped Carbon Nitride Quantum Dots as Self-Antibiofouling Dissolved Oxygen Sensor

Dissolved oxygen (DO) is a crucial indicator of the aquatic environment. The electrochemical DO sensor is renowned for superior precision. However, the unfavorable biofilm growth on the electrode surface and affect its sensitivity. H2O2, generated from the 2e- pathway ORR, emerges as a potent for degrading the biofilm attached on the electrode surface. Developing electrocatalyst material for selective 2e- pathway ORR that is challenging, while most are work for 4e- pathway. Herein, we design P-CNQD attaching to functionalized graphene (P-CNQD/Gr) that possesses highly selective 2e- pathway ORR. Upon the combination, the P-CNQDs were successful in altering the H2O2 selectivity, resulting in 85% H2O2 selectivity inside neutral medium. The reliable electrocatalyst with outstanding sensitivity and self-antibiofouling performance to be employed in fish farming Figure 1

Pt Loading of Phosphorus-Doped Carbon Nanotube Aerogels in Fuel Cell-Type Gas Sensors for Ultrasensitive H2 Detection.

A phosphorus-doped carbon nanotube (CNT) aerogel as the support material was loaded with Pt nanoparticles in fuel cell-type gas sensors for ultrasensitive H2 detection. The high surface area of the CNT scaffold is favorable to providing abundant active sites, and the high electrical conductivity facilitates the transport of carriers generated by electrochemical reactions. In addition, the CNT aerogel was doped with phosphorus (P) to further enhance the conductivity and electrochemical catalytic activity. As a result, the fuel cell-type gas sensor using the Pt/CNT aerogel doped with the optimal P content as the sensing material shows considerable performance for H2 detection at room temperature. The sensor exhibits an ultrahigh response of -921.9 μA to 15,000 ppm of H2. The sensitivity is -0.063 μA/ppm, which is 21 times higher than that of the conventional Pt/CF counterpart. The sensor also exhibits excellent repeatability and humidity resistance, as well as fast response/recovery; the response/recovery times are 31 and 4 s to 3000 ppm of H2, respectively. The modulation of the structure and catalytic properties of the support material is responsible for the improvement of the sensor performance, thus providing a feasible solution for optimizing the performance of fuel cell-type gas sensors.

Enhancing the production of PHA in Scenedesmus sp. by the addition of green synthesized nitrogen, phosphorus, and nitrogen–phosphorus-doped carbon dots

Plastic consumption has increased globally, and environmental issues associated with it have only gotten more severe; as a result, the search for environmentally friendly alternatives has intensified. Polyhydroxyalkanoates (PHA), as biopolymers produced by microalgae, might be an excellent option; however, large-scale production is a relevant barrier that hinders their application. Recently, innovative materials such as carbon dots (CDs) have been explored to enhance PHA production sustainably. This study added green synthesized multi-doped CDs to Scenedesmus sp. microalgae cultures to improve PHA production. Prickly pear was selected as the carbon precursor for the hydrothermally synthesized CDs doped with nitrogen, phosphorous, and nitrogen–phosphorous elements. CDs were characterized by different techniques, such as FTIR, SEM, ζ potential, UV–Vis, and XRD. They exhibited a semi-crystalline structure with high concentrations of carboxylic groups on their surface and other elements, such as copper and phosphorus. A medium without nitrogen and phosphorous was used as a control to compare CDs-enriched mediums. Cultures regarding biomass growth, carbohydrates, lipids, proteins, and PHA content were analyzed. The obtained results demonstrated that CDs-enriched cultures produced higher content of biomass and PHA; CDs-enriched cultures presented an increase of 26.9% in PHA concentration and an increase of 32% in terms of cell growth compared to the standard cultures.

Ratiometric fluorescence detection of tetracycline in milk and tap water with smartphone assistance for visual pH sensing using innovative dual-emissive phosphorus-doped carbon dots

Tetracycline (TC) is a common antibiotic that poses risks to human and animal health when present in samples. pH is a crucial parameter for assessing water quality and food safety. The innovative ratiometric probe, designed based on dual-emissive phosphorus-doped carbon dots (DE-P-CDs), was synthesized through a green hydrothermal process. The sensor exhibited high analytical performance toward TC detection with a LOD of 5.78 μM and 6.18 μM, respectively, and visual pH detection. Furthermore, the DE-P-CDs were employed for visual pH sensing, with the solution color smoothly changing with variations in pH. The color transitioned from red to orange, green to dark green, and blue to dark blue, facilitating easy visual observation. This probe proves to be a versatile tool for detecting TC in milk and tap water samples, with visual capabilities for pH. Two metric tools which were AGREE and BAGI were also used to evaluate the method's greenness. The evaluation affirmed its outstanding environmental friendliness. It represents a valuable contribution to the fields of analytical chemistry, food, and environmental monitoring.

NiFeCo alloy nanoparticles composited with phosphorus-doped vacancies-abundant carbon substrates as electrocatalyst for oxygen evolution reaction

Transition metal alloy nanoparticles are cost-effective electrocatalysts for oxygen evolution reactions. Preparing alloy catalysts with flexible controllability, high activity, and long-term stability is a challenge. By adjusting the proportion of metal atoms and engineering vacancies through their composite with a carbon substrate, we can enhance electron transfer and modulate the adsorption capacity of reaction intermediates. Herein, we synthesized a hybrid catalyst using Prussian blue analogs (PBAs) as the precursor, doped with Fe and Ni atoms, and subjected them to a defective engineering and phosphatization process. As an efficient alkaline OER electrocatalyst, the formation of the alloy increases the number of active sites, while the defect-rich phosphorus-doped carbon substrate improves internal electron transfer and mass transfer channels. The synthesized NiFeCoPC-1.5 electrocatalyst exhibits excellent catalytic activity with an overpotential of 211 mV at 10 mA cm−2 and a Tafel slope of 59 mV dec−1, and demonstrates good stability up to 1000 CV cycles. This work will expand the application of alloy nanoparticles in oxygen evolution electrodes.

Tungsten phosphide on nitrogen and phosphorus-doped carbon as a functional membrane coating enabling robust lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) hold great potential as future energy storage technology, but their widespread application is hampered by the slow polysulfide conversion kinetics and the sulfur loss during cycling. In this study, we detail a one-step approach to growing tungsten phosphide (WP) nanoparticles on the surface of nitrogen and phosphorus co-doped carbon nanosheets (WP@NPC). We further demonstrate that this material provides outstanding performance as a multifunctional separator in LSBs, enabling higher sulfur utilization and exceptional rate performance. These excellent properties are associated with the abundance of lithium polysulfide (LiPS) adsorption and catalytic conversion sites and rapid ion transport capabilities. Experimental data and density functional theory calculations demonstrate tungsten to have a sulfophilic character while nitrogen and phosphorus provide lithiophilic sites that prevent the loss of LiPSs. Furthermore, WP regulates the LiPS catalytic conversion, accelerating the Li-S redox kinetics. As a result, LSBs containing a polypropylene separator coated with a WP@NPC layer show capacities close to 1500 mAh/g at 0.1C and coulombic efficiencies above 99.5 % at 3C. Batteries with high sulfur loading, 4.9 mg cm−2, are further produced to validate their superior cycling stability. Overall, this work demonstrates the use of multifunctional separators as an effective strategy to promote LSB performance.

Phosphorus Modulated Peroxidase-Like Activity of Carbon Dots for Colorimetric Detection of Acid Phosphatase.

The precise regulation of nanoenzyme activity is of great significance for application to biosensing analysis. Herein, the peroxidase-like activity of carbon dots was effectively modulated by doping phosphorus, which was successfully employed for sensitive, selective detection of acid phosphatase (ACP). Phosphorus-doped carbon dots (P-CDs) with excellent peroxidase-like activity were synthesized by a one-pot hydrothermal method, and the catalytic activity could be easily modulated by controlling the additional amount of precursor phytic acid. P-CDs could effectively catalyze the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMB oxidation products in the presence of hydrogen peroxide. While ACP was able to catalyze the hydrolysis of L-ascorbyl-2-phosphate trisodium salt (AAP) to produce ascorbic acid (AA), which inhibited the peroxidase-like activity of P-CDs, by combining P-CDs nanoenzymes and ACP-catalyzed hydrolysis the colorimetric method was established for ACP detection. The absorbance variation showed a good linear relationship with ACP concentration in the range of 0.4-4.0 mU/mL with a limit of detection at 0.12 mU/mL. In addition, the method was successfully applied to detect ACP in human serum samples with recoveries in the range of 98.7-101.6%. The work provides an effective strategy for regulating nanoenzymes activity and a low-cost detection technique for ACP.

Exploring Deactivation Reasons of Biomass-Based Phosphorus-Doped Carbon as a Metal-Free Catalyst in the Catalytic Dehydroaromatization of n-Heptane.

Catalytic dehydroaromatization of n-alkanes into high-value aromatics has garnered extensive interest from both academia and industry. Our group has previously reported that phosphorus-doped carbon materials exhibit high selectivity for C-H bond activation in the dehydroaromatization of n-hexane. In this study, using n-heptane as a probe, we synthesized biomass-based phosphorus-doped carbon catalysts to investigate the impact of hydrogen heat treatment and carbon deposition on catalyst structure. Despite achieving an initial conversion of n-heptane at approximately 99.6%, with a toluene selectivity of 87.9%, the catalyst activity fell quickly. Moreover, longer hydrogen treatment time and higher hydrogen concentrations were found to accelerate catalyst deactivation. Thermogravimetric analysis (TGA) and N2 adsorption measurements (BET) indicated that a small amount of coke deposition was not the primary cause of catalyst deactivation. Temperature-programmed desorption of ammonia gas (NH3-TPD) revealed a significant decrease in acid-active functional groups. X-ray photoelectron spectroscopy (XPS) and solid-state 31P NMR spectroscopy confirmed the reduction of active central phosphorus species. These results suggest that catalyst deactivation primarily arises from the decrease in acidity and the partial reduction of phosphorus-containing groups, leading to a substantial loss of active sites. This work contributes new perspectives to understanding the properties and design improvements of metal-free carbon catalysts.

A superior sodium-ion anode material from PAN/lignin-derived carbon nanofibers with inter-connected structure prepared through phosphoric acid induced cross-linking

A feasible route to fabricate phosphorus-doped carbon nanofibers (P-CNFs) with an inter-connected structure has been demonstrated through electrospinning, stabilization, and subsequent phosphoric acid impregnation and carbonization processes using polyacrylonitrile and lignin as carbon sources. The results illustrate that the phosphoric acid induced cross-linking could be beneficial to acquire the closed-pore structure and the heteroatom-doped surface chemistry of nanofibers. As a result, the P-CNFs exhibit higher interlayer spacing of graphite and lower BET specific surface area compared to the pristine CNFs. The P-CNFs as an anode material for sodium-ion batteries (SIBs) present a high reversible capacity 278 mA h g−1 at 0.2 A g−1 and a superior initial Coulomb efficiency (ICE) of 78.86 %. Moreover, the reversible capacity of P-CNFs can be stably maintained near the initial capacity after 5000 cycles at 1 A g−1, showing exceptional structural stability and cycling durability. Meanwhile, the sodium storage mechanism of P-CNFs was investigated using in-situ Raman and ex-situ XRD analysis to understand the exceptional structural stability and Na+ adsorption capacity of P-CNFs. This work provides valuable insights for the design of carbon nanofibers with an inter-connected structure as anode materials for SIBs, exhibiting outstanding electrochemical properties.

A phosphorus-doped carbon material derived from a sodium alginate/phosphoric acid hydrogel as an efficient catalyst for catalytic oxidation of furfural to maleic acid

A phosphorus-doped carbon material (PC-700) with high content of P was derived through the calcination of the alginate-H3PO4 xerogel. PC-700 exhibited excellent catalytic activity for the production of maleic acid from furfural in aqueous solution.

Phytic acid-assisted hybrid engineering of MOF-derived composites for tunable electromagnetic wave absorption

Hybrid engineering is gradually deemed as a powerful approach to solving the bottleneck problem of metal-organic framework (MOF) derived absorbers for practical application. Herein, a new type of semiconductor/carbon-based hybrid material was successfully prepared by phytic acid (PA) modification and carbonization of MOF/bacterial cellulose (BC) precursors, which remedied the drawbacks of structural instability, lethal byproducts and complicated steps reported previously. Specifically, the obtained Fe(PO3)2@C/phosphorus-doped carbon foam (Fe(PO3)2@C/PCF) had a 3D hybrid micro-nanostructure that integrated spatial microcurrent network, multi-level pores, heterogeneous interfaces and lattice defects, showing its unique advantages of low filler content (15 wt.%), moderate surface reflectivity, multi-band microwave absorption and radar stealth. The experimental analysis and CST simulation further revealed that PA dosage can precisely adjust the hybrid phase content, pore texture and electromagnetic parameters of the final product to achieve synergistic enhancement of multiple dielectric response, impedance matching and attenuation capacity. As a result, an effective bandwidth (EAB) of 6 GHz and a minimum reflection loss (RLmin) of −57.0 dB were obtained in the Ku- and C-bands, respectively. These encouraging results may advance the development of novel MOF-derived absorbents based on the hybridization principle.

CoO quantum dots anchored on P-doped carbon nitride improves peroxymonosulfate activation to degrade sulfamethoxazole

The development of highly dispersed and ultra-small size cobalt-loaded catalysts is crucial for achieving efficient and low secondary pollution in peroxymonosulfate (PMS) activation processes. Herein, a phosphorus-doped carbon nitride (PCN) loaded with CoO quantum dot catalyst (Co80-PCN) was derived from the mixture of BINAP-CoCl2 complex (BINAP = 1,1′-binaphthyl-2,2′-diphosphine) and carbon nitride (CN). Structural studies revealed that cobalt oxide quantum dots with an average diameter of 9.99 nm were evenly and securely attached to the PCN substrate. The optimal Co80-PCN/PMS system demonstrated an almost 100% degradation efficiency of sulfamethoxazole (SMX, 10 mg/L) within 15 min, with a reaction rate constant of 0.3341 min−1, which was 30.1 times higher than that of the CN/PMS system. This outstanding degradation performance could be primarily attributed to the enhanced catalytic activity of CoO quantum dots and the improved electronic structure resulting from P-doped CN. This work offers valuable insights for the future design of carbon material loaded quantum dot catalysts.