Phosphorus Co-doping Research Articles

Three-dimensional N,P co-doped graphene hydrogel cathode for zinc-ion hybrid capacitor with high specific capacitance and excellent rate performance

Zinc-ion hybrid capacitor (ZHSC) is recognized as a favorable energy storage device due to the combined advantages of battery-type anode and capacitor-type cathode. However, it still remains a huge challenge to achieve a high-specific-capacitance cathode without compromising the rate capability for high-performance ZHSC. Here, a three-dimensional hierarchical nitrogen and phosphorus co-doped reduced graphene oxide hydrogel (NPGH) is synthesized with small-sized graphene oxide precursors via one-step hydrothermal reduction and in-situ doping, which is firstly used as cathode for ZHSC without adding extra conductive additives and binders. In this case, small-sized graphene sheets can increase and shorten ions diffusion channels for the efficient utilization of active surface compared with commonly-used large-sized counterparts. Moreover, nitrogen and phosphorus co-doping can synergistically enhance the conductivity, provide additional active sites, and promote the adsorption of zinc ions, which is well demonstrated by electrochemical analysis, ex situ characterization and DFT theoretical calculation. Attributed to the synergy, NPGH-based ZHSC displays large specific capacitance (251.3 F g−1, 0.5 A g−1), outstanding rate performance (79 %, 50 A g−1) and excellent cycle stability. This work proposes a novel strategy of tailoring rGO cathode by simultaneous size effect and doping engineering, which shows a great promise of constructing high-performance rGO based ZHSC.

Properties of phosphorus-boron co-doped c-Si quantum dots/SiNx:H thin film prepared by PECVD in-situ deposition

Co-doping of phosphorus and boron elements into crystalline silicon quantum dot (c-Si QD) is an effective approach for enhancing the photoluminescence (PL) performance. In this paper, we report on the preparation of hydrogenated silicon nitride (SiNx:H) thin films embedded with phosphorus-boron co-doped c-Si QDs via plasma enhanced chemical vapor deposition route. Mixed dilution including hydrogen (H2) and argon (Ar) is applied in the in-situ deposition process for optimizing the deposition process. The P-B co-doped c-Si QD/SiNx:H thin films exhibit a wide range of PL spectra. The emission is greatly improved especially for the short-wavelength light when compared to the SiOx:H thin film containing P-B co-doped c-Si QDs. The effects of H2/Ar flow ratio on the structural and optical characteristics of thin films are systematically investigated through a series of characterizations. Experimental results show that various properties, such as crystallinity, QD size, optical band gap and doping concentrations, are effectively controlled by tuning H2/Ar flow ratio. Based on the red-shift of QCE-related PL peak, the successful P-B co-doping into Si QDs are verified. Finally, a comprehensive discussion has been made to analyze the influence of H2-Ar mixed dilution on the film growth and impurity doping in detail in this paper.

Insights into the roles of nitrogen and phosphorus co-doping for efficient methanol electrooxidation

Anchoring Pt onto multi-heteroatom doped carbon materials has been recognized as an effective approach to improve the performance of electrocatalytic methanol oxidation. However, distinct contributions and specific behavior mechanisms of different heteroatoms, notably N and P, the specific behavior mechanisms in synergistically promoting Pt NPs remain elusive. In this work, we construct 1D N and P co-doped carbon nanotube (N, P-CNTs) supports with abundant defect anchors for Pt. The as-prepared Pt/N, P-CNTs exhibit outstanding activity and exceptional stability in methanol oxidation reaction (MOR), achieving high mass activity up to 6481.3 mA mg−1Pt. Moreover, they can retain 90.5 % of their initial current density even after 800 cycles tests. Detailed characterizations and theoretical calculations indicate that the robust strong metal-support interactions (SMSI) effect caused by N doping within the unique N and P co-doped coordination structure controllably regulate the coordination environment of Pt, reduce the d-band center of Pt, thus promoting the adsorption and decomposition of CH3OH. However, P doping weakens the adsorption strength of CO on the Pt active site by sacrificing partial electron transfer, accelerating the oxidative conversion of the CO-like poisoning species (COads). Significantly, the synergistic mechanism of N and P species on the modification of Pt’s electronic structure and its subsequent impact on the electrocatalytic methanol oxidation behaviors on the Pt surface was thoroughly elucidated, providing a constructive route for designing robust MOR electrocatalysts with high MOR activity and durability.

First-Principles Calculations of P-B Co-Doped Cluster N-Type Diamond

To achieve n-type doping in diamond, extensive investigations employing first principles have been conducted on various models of phosphorus doping and boron–phosphorus co-doping. The primary focus of this study is to comprehensively analyze the formation energy, band structure, density of states, and ionization energy of these structures. It is observed that within a diamond structure solely composed of phosphorus atoms, the formation energy of an individual carbon atom is excessively high. However, the P-V complex substitutes 2 of the 216 carbon atoms, leading to the transformation of diamond from an insulator to a p-type semiconductor. Upon examining the P-B co-doped structure, it is revealed that the doped impurities exhibit a tendency to form more stable cluster configurations. As the separation between the individually doped atoms and the cluster impurity structure increases, the overall stability of the structure diminishes, consequently resulting in an elevation of the ionization energy. Examination of the electronic density of states indicates that the contribution of B atoms to the impurity level is negligible in the case of P-B doping.

Binary nonmetal boron and phosphorus co-doping into PdRh nanosheets boosts electro‑upgrading polyethylene terephthalate

The upcycling of plastic waste through electrochemistry has garnered significant interest. In this study, we present a two-step strategy for synthesizing boron (B) and phosphorus (P) co-doped quaternary PdRhBP nanosheets (PdRhBP NSs) aimed at converting polyethylene terephthalate (PET) plastic hydrolysate (ethylene glycol) into high-value-added chemicals. The electrocatalytic performance of PdRhBP NSs for ethylene glycol (EG) oxidation surpasses that of PdRh nanosheets (PdRh NSs) and commercial Pd black. Notably, the highest contents of glycolic acid (GA) and formate are observed at a voltage of 0.755 V. This can be attributed to the two-dimensional structural advantages of PdRhBP NSs and the synergistic effect of B and P, optimizing the electronic configuration of Pd. This study not only proposes a double-doping strategy for designing efficient electrochemical conversion catalysts but also presents a green and sustainable approach for upgrading and utilizing plastic waste.

Synergetic regulation of electronic structure of graphitic carbon nitride through phosphorus and carbon co-doping for enhanced photocatalytic CO2 reduction

Graphitic carbon nitride (CN) is a promising candidate for visible-light CO2 photoreduction, but suffers severe charge recombination due to its intrinsic π-conjugated skeleton. Herein, exogenous phosphorous (P) and carbon (C) are co-doped into the polymeric structure of CN to modulate the electronic structure. In virtue of the different electronegativity and valence electron structure of the co-dopants, an internal driving force is formed within the π-conjugated framework, which greatly accelerates the charge transfer and separation. The P and C co-doped CN (PCCN) exhibits a significantly improved CH4 evolution rate (41.85 μmol g−1h−1) under visible light irradiation, which is 12.5 times higher than the pristine CN. The P and C co-doping causes enhanced light absorption, promoted CO2 adsorption as well as inbuilt charge centers for efficient charge separation. This work offers new insights into the mutual effect of co-dopants on electronic structure rearrangement of novel photocatalysts for elevated photocatalytic activity.

Phosphorus and Nitrogen Codoped Porous Carbon Nanosheets for Energy Storage and Gas Adsorption

Phosphorus and Nitrogen Codoped Porous Carbon Nanosheets for Energy Storage and Gas Adsorption

First-principles study of effect of impurity compensation on optical properties of Si

Presently, impurity-compensated silicon (Si) has no clear potential applications due to high resistance and few carriers. Thus, it has received little attention from researchers. In this study, we find that impurity compensation can make localized state energy levels form in Si bandgap, which can improve the light absorption of Si in the near infrared region. In this work, in order to comprehensively and deeply understand the photoelectric properties of impurity-compensated Si, the localized state energy levels composed of P<sup>+</sup>/B<sup>–</sup> ions are constructed in Si bandgap through the co-doping of phosphorus (P) and boron (B), thereby forming impurity-compensated Si. The first-principles based on a density functional theory framework is used to study the photoelectric properties of the impurity-compensated Si (n/p-Sic) such as the density of states (DOS), dielectric function and refractive index. The DOS study reveals the following results: after the n- and p-Si with the same concentration of P and B (12.5%) are fully compensated for by impurities, the Fermi energy levels of their compensated counterparts are at the valley bottom formed by the two adjacent DOS peaks, and the DOS is not zero at the valley bottom. In the study of dielectric function and refractive index, it is found that when the doping ratio is <i>C</i><sub>B</sub>/<i>C</i><sub>P0</sub> = 0.25, n-Sic has the largest dielectric function and refractive index in the low energy region. In addition, comparing intrinsic Si with its doped counterparts in the real part (Re) of their dielectric constant, the following regularity is found: in the high energy region of <i>E</i> > 4 eV, the Re values of the intrinsic Si, n/p-Si and p-Sic are negative. In the low energy region of 0.64 eV< <i>E</i> < 1.50 eV, the Re value of n-Sic is negative for the doping ratio of <i>C</i><sub>B</sub>/<i>C</i><sub>P0</sub> = 0.25. The above comparison indicates that the n-Sic with <i>C</i><sub>B</sub>/<i>C</i><sub>P0</sub> = 0.25 can achieve good metallicity in the low energy region, indicating that the electrons in valence band are easily excited by low-energy long-wavelength light. Theoretical studies show that the good photoelectric properties of n-Sic with <i>C</i><sub>B</sub>/<i>C</i><sub>P0</sub> = 0.25 may be related to Si dangling bonds and localized state energy levels in Si bandgap. The Si dangling bonds are caused by the impurity compensation of B dopant for n-Si, leading part of Si-Si bonds to change into Si-B bonds. This study provides theoretical guidance for the application of impurity-compensated Si in the field of photodetectors such as CMOS image sensors and infrared photodetectors.

Phosphorus dopants triggered single-atom platinum catalysis for efficient hydrogen evolution in proton exchange membrane electrolyzers

A single-atom Pt and phosphorus co-doping strategy is applied to a nanoporous MoS2 catalyst, where P dopants could modulate the electronic structure around Pt atoms, leading to significantly improved activity for PEM electrolyzer applications.

A Ni-Fe-V trimetallic phosphorus-selenium composite supported on carbon cloth as freestanding electrocatalyst for oxygen evolution reaction

Developing highly active non-noble metal oxygen evolution reaction (OER) electrocatalysts is still urgent and significant to enable the large-scale hydrogen production. Herein, we propose a freestanding electrocatalyst of Ni-Fe-V trimetallic phosphorus-selenium composite on carbon cloth (NiV2P/FeSe@CC) for this issue, which is realized by the in-situ growth of V-MOF, the introduction of Ni and Fe components by electrodeposition, and the synchronous phosphatization and selenization treatment. The well-designed composite exhibits an excellent electrical conductivity and multi-level pore structure, which makes for rapid charge/mass transport and sufficient exposure of catalytic sites. The electrochemical deposition process allows Ni and Fe components to be uniformly deposited on the V-MOF, while the phosphorus and selenium co-doping can modulate the catalyst electronic structure and promote the adsorption of reaction intermediates, thus improving the OER catalytic activity. Consequently, the freestanding electrocatalyst exhibits an ultra-low overpotential of 168 mV under a current density of 10 mA cm−2 and a small Tafel slope of 44.32 mV dec-1 in alkaline environment. The outstanding performance is maintained in the integrated electrolyzer, presenting a small voltage of 1.53 V getting a current density of 10 mA cm−2 and an ultrastability for 160 h under 100 mA cm−2.

Phosphorus and Nitrogen Codoped Carbon Nanoparticles as Both Anode and Cathode Materials with Enhanced Li+/PF6– Storage for High Energy Density Lithium-Ion Capacitors

Phosphorus and Nitrogen Codoped Carbon Nanoparticles as Both Anode and Cathode Materials with Enhanced Li⁺/PF₆^– Storage for High Energy Density Lithium-Ion Capacitors

Boosted photogenerated charge carrier separation by synergy of oxygen and phosphorus co-doping of graphitic carbon nitride for efficient 2-chlorophenol photocatalytic degradation

Although graphitic carbon nitride (g-C3N4) has been attracted with its unique band structure, the ease of recombination of charge and the poor light-capturing capability limits its application in degradation of organic pollutants. Herein, via simple one-step thermal polymerization, oxygen and phosphorus dopants are simultaneously introduced into the heptazine unit of g-C3N4. The obtained O and P co-doped g-C3N4 could completely remove 2-chlorophenol (2-CP) in 30 min, much superior to bulk g-C3N4. The density functional theory (DFT) calculations and experimental characterization demonstrate that the synergy of O and P co-doping leads to the changes in bandgap structure, thus obviously enhancing the light-capturing capability and promoting the charge carrier separation. Moreover, the synergy of O and P co-doping facilitates the adsorption and enrichment of oxygen molecules at phosphorus sites, contributing to the generation of abundant reactive oxygen radicals. These radicals actively participate in the subsequent degradation of organic pollutants.

Hydrothermal Synthesis of Nitrogen and Phosphorus Codoped Carbon Dot Interfacial Modification Layer for Efficient Charge Transfer between ZnO Electron Transport Layer and PTB7:PC70BM Active Layer

The interface between the active layer and the charge-transporting layer is critical for performance improvement in polymer solar cells (PSCs). The use of zinc oxide (ZnO) as an electron transport layer (ETL) in PSCs was limited due to inherent defects in the surface of ZnO prepared by the sol-gel method, mismatched energy bands with the photoactive layer, and incompatibility between the photoactive layer and ZnO ETL. In this study, nitrogen and phosphorus codoped carbon dots (N & P-CDs) were prepared from Ensete ventricosum (false banana) and used as an interfacial modification layer for ZnO ETL. The inverted devices with structures ITO/ZnO/N & P-CD/PTB7:PC70BM/Al were fabricated to investigate the charge transfer dynamic between the active layer and ETL interface modification with N & P-CDs. We have observed that the interfacial modification between the ZnO ETL and the active layer, using N & P-CDs, improves the charge transfer between ZnO ETL and PTB7:PC70BM active layer. The obtained result shows that the ETL/BHJ interface resistance of the devices with ZnO:undoped CDs, ZnO:N-CDs, ZnO:P-CDs, and ZnO:N & P-CD ETLs decreases dramatically from 103.4 to 84.04, 78.16, 37.88, and 28.9 Ω, respectively. This is due to the improvement of charge extraction efficiency by smoothing ZnO surface defects and minimizing the band mismatch between the active layer and ZnO using N & P-CDs. The results indicate that the water-soluble N & P-CDs developed in this study have the potential to be used for efficient free charge carrier extraction for PSCs.

Boron–Phosphorus Codoped Coral-like Hard Carbon Anodes for Sodium Ion Storage

Hard carbon materials have the advantages of low price, environmental friendliness, and good electrical conductivity but have the disadvantages of unsatisfactory sodium storage capacity and low long-cycle stability. The use of heteroatom doping and structural design can significantly improve the sodium storage properties of carbon materials. In this paper, a boron–phosphorus doped hard carbon material (CABP) was designed by using citric acid as the carbon source. The rich pore structure of CABP also provides fast transport channels for Na+, while the efficient doping of B and P atoms can distort the graphitic layer and generate more active sites and defects. The CABP carbon material therefore exhibits excellent electrochemical properties. It can obtain pretty good capacities of 246.8 mA h g–1 after 400 cycles at 0.1 A g–1. Moreover, it was able to maintain 161.9 mA h g–1 after 5000 cycles at 5 A g–1. This work provides a new route for the facile preparation of high-performance heteroatom-doped carbon materials and an idea for the preparation of diatom-doped materials for energy storage.

Fast-Charging Sodium-Ion Batteries Enabled by Molecular-Level Designed Nitrogen and Phosphorus Codoped Mesoporous Soft Carbon.

Soft carbons have attracted extensive interests as competitive anodes for fast-charging sodium-ion batteries (SIBs); however, the high-rate performance is still restricted by their large ion migration barriers and sluggish reaction kinetics. Herein, we show a molecular design approach toward the fabrication of nitrogen and phosphorus codoped mesoporous soft carbon (NPSC). The key to this strategy lies in the chemical cross-linking reaction between polyphosphoric acid and p-phenylenediamine, associated with pyrolysis induced in-situ self-activation that creates mesoporous structures and rich heteroatoms within the carbon matrix. Thanks to the enlarged interlayer spacing, reduced ion diffusion length, and plentiful active sites, the obtained NPSC delivers a superb rate capacity of 215 mAh g-1 at 10 A g-1 and an ultralong cycle life of 4,700 cycles at 5 A g-1. Remarkably, the full cell shows 99% capacity retention during 100 continuous cycles, and maximum energy and power densities of 191 Wh kg-1 and 9.2 kW kg-1, respectively. We believe that such a synthetic protocol could pave a novel venue to develop soft carbons with unique properties for advanced SIBs.

Enhancing flame retardant property of graphene oxide via phosphorus and nitrogen co-doping

A simple and versatile method has been developed to efficiently enhance the flame retardant of graphene oxide (GO) by adding ammonium phosphate (AP) into GO. The as-made GO/AP exhibits excellent flame retardant properties, which emits some smoke at the beginning without catching any fire and any observable shrinkage. In contrast, the GO catches fire within several seconds and completely burns out. The improvement of flame retardancy can be attributed to the formation of CP and CN bonds with heat. This simple and effective technique of the introduction of P and N can be adopted for inexpensive mass production of GO/AP for many practical applications such as sensors, energy-storing materials, and nanomaterial electronics.

Boron and Phosphorus Co-Doped Graphitic Carbon Nitride Cooperate with Bu4NBr as Binary Heterogeneous Catalysts for the Cycloaddition of CO2 to Epoxides

The development of a cost-effective heterogeneous catalytic system for the cycloaddition reaction of CO2 and epoxides is of great importance. In this manuscript, three kinds of boron and phosphorus co-doping graphitic carbon nitride (BP-CN) were prepared and characterized. Among them, BP-CN-1 displayed the optimal catalytic performance in the presence of Bu4NBr (tetrabutylammonium bromide) for the CO2 cycloaddition with propylene oxide, and 95% propylene carbonate yield was obtained under a 120 °C, 2 MPa, 6 h condition. Moreover, the BP-CN-1/Bu4NBr catalytic system is compatible with various epoxides and also exhibits excellent recycling performance under metal- and solvent-free conditions. Hence, BP-CN-1 exhibited an attractive application for the efficient fixation of CO2 due to the simple, eco-friendly synthesis route and effective catalytic activity.

Nitrogen and phosphorus co-doped carbon for improving capacity and rate performances of potassium ion batteries

The carbon material is considered as the promising anode for potassium ion battery owing to the merits of wide source and structural robustness. However, the limited capacity and the slow kinetics limit the development of carbon materials. Herein, the porous nitrogen-and-phosphorus co-doped carbon material are prepared using the O2-NH3 reactive pyrolysis of cellulose with the additional phosphating treatment. As compared with the pristine carbon obtained by the direct pyrolysis of cellulose, the capacity of nitrogen-and-phosphorus co-doped carbon rises from 140 to 253 mAh g−1, and the capacity increases significantly even at high current density (from 16 to 76 mAh g−1 at 20 A g−1). Under the guidance of theoretical simulation, the enhancement of potassium storage capacity and kinetics is explored by combining spectral characterization and electrochemical research. On this basis, the synergistic effect of nitrogen and phosphorus co-doping can improve the potassium storage performance. This study has reference significant for heteroatom modification of carbon materials for potassium storage anodes.

Structural Engineering of Cobalt-Free Perovskite Enables Efficient and Durable Oxygen Reduction in Solid Oxide Fuel Cells.

Developing low-cost, efficient, and durable cobalt-free perovskite oxides for oxygen reduction reaction at intermediate-to-low temperatures is crucial to enhance the viability of solid oxide fuel cells (SOFCs), a promising ingredient for establishing a more sustainable future. Herein, a highly active and robust cobalt-free perovskite Ba0.75 Sr0.25 Fe0.95 P0.05 O3-δ (BSFP) oxygen electrode via a facile co-doping strategy for intermediate-to-low temperature SOFCs (ILT-SOFCs) is reported by a combined experimental and theoretical approach. Attributed to stable and oxygen defect-rich structure, and remarkable intrinsic oxygen transport kinetics, the BSFP cathode shows exceptional catalytic performance, including record-level power output among iron-based perovskite cathodes (1464mW cm-2 at 600 °C), low area-specific resistance (≈0.1 Ω cm2 at 600 °C), robust stability both in symmetrical and single cell configurations, and outstanding CO2 tolerance/reversibility. The first-principle calculations validate the role of co-doping of strontium and phosphorus for the high activity and durability. Central to this work is the combined experiment-calculation approach to point to an effective strategy in the development of highly active and stable perovskite-type cathodes for ILT-SOFCs and related applications.

Enhanced subband light emission from Si quantum dots/SiO2 multilayers via phosphorus and boron co-doping.

Seeking light sources from Si-based materials with an emission wavelength meeting the requirements of optical telecommunication is a challenge nowadays. It was found that the subband emission centered near 1200 nm can be achieved in phosphorus-doped Si quantum dots/SiO2 multilayers. In this work, we propose the phosphorus/boron co-doping in Si quantum dots/SiO2 multilayers to enhance the subband light emission. By increasing the B co-doping ratio, the emission intensity is first increased and then decreased, while the strongest integrated emission intensity is almost two orders of magnitude stronger than that of P solely-doped sample. The enhanced subband light emission in co-doped samples can be attributed to the passivation of surface dangling bonds by B dopants. At high B co-doping ratios, the samples transfer to p-type and the subband light emission from phosphorus-related deep level is suppressed but the emission centered around 1400 nm is appeared.