Nitrogen-doped Porous Carbon Nanosheets Research Articles

Nitrogen-doped porous carbon nanosheets derived from furfural residue as an oxygen reduction catalyst

The complex pore structure of porous carbon plays a pivotal role in determining the catalytic activity of catalysts involved in the oxygen reduction reaction (ORR), and template methods have emerged as the gold standard in the fabrication of porous carbon. This study describes the preparation of a series of carbon materials that use furfural residue and urea as carbon and nitrogen sources, respectively, in conjunction with KOH as an activating agent through a template method. The prepared catalysts have a large specific surface area and an abundance of micro/mesoporous structures, both of which facilitate ion transport and promote active site exposure. Notably, the sample with a carbon-to-nitrogen mass ratio of 1:4 (FR/C-4) exhibits an exceptionally high specific surface area (2190 m2 g−1) along with an impressive array of pore structures. Compared with commercial Pt/C, FR/C-4 demonstrates superior ORR catalytic activity with a half-wave potential (E1/2) of 0.88 V. Furthermore, FR/C-4 demonstrates remarkable stability and methanol tolerance in alkaline electrolytes, indicating its potential for a wide range of applications, such as fuel cells and metalair batteries.

High-Entropy Ag-Ru-Based Electrocatalysts with Dual-Active-Center for Highly Stable Ultra-Low-Temperature Zinc-Air Batteries.

The development of advanced bifunctional catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is significant for rechargeable zinc-air batteries (ZABs). Herein, a unique dual active center alloying strategy is proposed to achieve the efficient bifunctional oxygen catalysis, and the high entropy effect is further exploited to modulate the structure and performance of the catalysts. The MOF-assisted pyrolysis-replacement-alloying method was employed to construct the CoCuFeAgRu high-entropy alloy (HEA), which are uniformly anchored in porous nitrogen-doped carbon nanosheets. Notably, the obtained HEA catalyst exhibits excellent catalytic performance for both ORR and OER, and a peak power density of 136. 53 mW cm-2 and an energy density of 987.9 mAh gZn -1, surpassing the most of the previously reported bifunctional oxygen electrocatalysts. Moreover, the assembled flexible rechargeable ZAB enables excellent performance even at the ultralow temperature of -40 °C, with an energy density of 601.6 mAh gZn -1 and remarkable cycling stability up to 1,650 hours. Combined experimental and theoretical calculation results reveal that the excellent bifunctional catalytic activity of the HEA catalyst originated from the synergistic effect of the Ag and Ru dual active centers, and the optimization of the electronic structure by alloying effect.

“One stone, two birds”: Salt template enabling porosity engineering and single metal atom coordinating toward high-performance zinc-ion capacitors

Zinc-ion hybrid capacitors (ZIHCs) have received increasing attention as energy storage devices owing to their low cost, high safety, and environmental friendliness. However, their progress has been hampered by low energy and power density, as well as unsatisfactory long-cycle stability, mainly due to the lack of suitable electrode materials. In this context, we have developed manganese single atoms implanted in nitrogen-doped porous carbon nanosheets (MnSAs/NCNs) using a metal salt template method as cathodes for ZIHCs. The metal salt serves a dual purpose in the synthesis process: It facilitates the uniform dispersion of Mn atoms within the carbon matrix and acts as an activating agent to create the porous structure. When applied in ZIHCs, the MnSAs/NCNs electrode demonstrates exceptional performance, including a high capacity of 203 mAh g−1, an energy density of 138 Wh kg−1 at 68 W kg−1, and excellent cycle stability with 91% retention over 10,000 cycles. Theoretical calculations indicate that the introduced Mn atoms modulate the local charge distribution of carbon materials, thereby improving the electrochemical property. This work demonstrates the significant potential of carbon materials with metal atoms in zinc-ion hybrid capacitors, not only in enhancing electrochemical performance but also in providing new insights and methods for developing high-performance energy storage devices.

ZIF-12-derived nitrogen doped porous carbon nanosheets-functionalized with silver nanoparticles for ratiometric molecularly-imprinted electrochemical sensing of D-penicillamine

In this work, an electrochemical platform was developed for detection of D-pencillamine utilizing highly responsive molecularly imprinted polymers (MIPs). This platform operates on a ratiometric principle and is constructed on nitrogen-doped porous carbon nanosheets (N-PCNS) derived from zeolite imidazolate frameworks (ZIF-12) in the presence of saturated solution of zinc sulfate. Subsequently, silver nanoparticles (Ag) were introduced onto the surface of N-PCNS/GCE to enhance conductivity and surface area, and serve as a standard signal. The MIP layer was formed on the Ag@N-PCNS/GCE surface through o-phenylenediamine (o-phen) electro-polymerization in the presence of the D-pencillamine (D-PAN) as a template. Detection of D-PAN relies on measuring ID-PAN/IAg response ratio employing differential pulse voltammetry (DPV). This ratio exhibits a linear correlation with the concentration of D-PAN in the dynamic linear range of 0.161–170 µM, exploiting LOD of 38.0 nM (S/N = 3). The electrochemical sensor offers numerous advantages including low detection limit, accuracy, stability, and sufficient degree of selectivity. Utilizing this platform, D-PAN-containing samples were efficiently analyzed with recovery percentages of 98.0–102.0 % and RSDs of 2.78–3.89 %, demonstrating the accuracy of the method.

In-situ approach to porous nitrogen-doped carbon nanosheets functionalized by Brønsted acidic ionic liquids for microwave-assisted upgrading fructose to 5-hydroxymethylfurfural

In the search for robust and recoverable supported Brønsted acidic ionic liquids (BAILs) catalysts for efficient upgrading bio-sugars to value-added chemicals, an in-situ strategy of supramolecular preorganization-thermal polycondensation is designed to fabricate porous ultrathin nitrogen-doped carbon nanosheets (NCNSs), and then BAILs-functionalized NCNSs catalysts are prepared via successive quaternary ammonization by sultones and anion exchange with Brønsted acids. By adjusting the molar composition of the starting monomers, the textural properties of NCNSs supports are tuned; and by functionalization with different sultones (1,3-propanesultone and 1,4-butanesultone) and organic (trifluoromethanesulfonic acid and p-toluenesulfonic acid) or inorganic (H2SO4 and H3PO4) acids, the surface hydrophobicity and Brønsted acid strength of the catalysts are regulated. The catalysts are applied in microwave-assisted upgrading fructose to 5-hydroxymethylfurfural, and influences of Brønsted acid nature, surface hydrophobicity and textural properties on the catalytic performance are explored. For the most active [C4SO3HN][OTf]-NCNSs-MA-3 catalyst with the advantages of superstrong Brønsted acidity, higher surface hydrophobicity and perfect porous ultrathin sheet-like nanostructure, the conversion of fructose and the yield of 5-hydroxymethylfurfural of 100% and 87.7% are achieved after microwave irradiation for 15 min, outperforming Amberlyst-15 resin and HY zeolite. The catalysts also demonstrate the robust catalytic reusability, and after five consecutive catalytic runs, the obvious activity loss hardly occurs, along with little acid sites leaching.

In-situ construction of nitrogen-doped porous carbon nanosheets supported well-dispersed Fe3O4 nanoparticles for efficient purification of antibiotic wastewater via peroxydisulfate activation

Heterogeneous catalysts composed of transition metal oxides and carbon-based materials have displayed significant potential in persulfates activation for the elimination of diverse refractory organic pollutants. Herein, the nitrogen-doped porous carbon (N-pC) nanosheets supported well-dispersed Fe3O4 nanoparticles (Fe3O4/N-pC) were meticulously designed and fabricated. This fabrication process involved the creation of Fe3+/(CN@PDA) precursor through loading polydopamine-Fe3+ complex on graphitic carbon nitride (g-C3N4) and the following calcination process, resulting in in-situ formation of Fe3O4 nanoparticles on the N-pC nanosheets that were derived from polydopamine coated g-C3N4. The large specific surface area, coupled with accessible Fe2+/Fe3+ species, facilitated the synergy of adsorption and catalysis, enabling the rapid elimination of antibiotics via peroxydisulfate (PDS) activation. The optimal Fe3O4/N-pC catalyst demonstrated a remarkable efficacy in the degradation of tetracycline-hydrochloride (TC), reaching a quasi-first-order kinetic constant of 0.1479 min−1, which was 1.95 times that of the degradation reaction using g-C3N4 (0.0758 min−1). Mechanistic investigations revealed that both radicals (·O2-,·OH and SO4·-) and non-radical (1O2 and electron transfer) oxidation pathways were involved in TC degradation. The toxicities of degradation intermediates were assessed through a bean-sprout planting experiment and the quantitative structure-activity relationship (QSAR) analysis. This work offers some guidance on the preparation and application of heterogeneous catalysts for effectively removing organic contaminants from water.

2D metal–organic framework derived ultra-thin nitrogen-doped oxygen rich porous carbon nanosheets for zinc-ion hybrid supercapacitors

2D MOF derived ultra-thin carbon nanosheets with high reactivity, super-hydrophilicity and hierarchical porosity are prepared. The corresponding Zn-ion hybrid supercapacitor delivers exceptional energy storage capability with long cycling stability.

Nickel single-atom catalysts on porous carbon nanosheets for high-performance lithium-selenium batteries

Lithium-selenium (Li–Se) batteries have attracted intensive attention due to the high theoretical volumetric capacity (3253 mA h cm−3) and high electrical conductivity (1 × 10−3 S m−1) of selenium. However, the shuttle effect, rapid capacity fading and sluggish electrochemical process of the lithium selenides limit its further application. Herein, a catalyst of nickel single atoms (SA)/nitrogen-doped porous carbon nanosheets (Ni-NC) has been constructed and applied as an ideal host for selenium cathode. Such a material allows the adsorption of lithium selenides while the Ni SA serves as efficient catalytic site for the conversion of these selenides during charge/discharge process, as the theoretical calculation results suggest that the Ni SA could enhance the binding energy of the carbon host towards the intermediates and improve the electron transfer. As expected, the Ni-NC/Se cathode exhibits a capacity of 495 mAh g−1 at 0.2 C and 311 mAh g−1 at 4 C and good cycling stability of 225 mAh g−1 after 1000 cycles at 4 C with a Coulombic efficiency of ∼100 %, significantly better than the pure carbon host without Ni SA sites.

2D MOF-assisted Pyrolysis-displacement-alloying Synthesis of High-entropy Alloy Nanoparticles Library for Efficient Electrocatalytic Hydrogen Oxidation.

Multimetallic alloy nanoparticles (NPs) have received considerable attention in various applications due to their compositional variability and exceptional properties. However, the complexity of both the general synthesis and structure-activity relationships remain the long-standing challenges in this field. Herein, we report a versatile 2D MOF-assisted pyrolysis-displacement-alloying route to successfully synthesize a series of binary, ternary and even high-entropy NPs that are uniformly dispersed on porous nitrogen-doped carbon nanosheets (PNC NSs). As a proof of utility, the obtained Co0.2Ru0.7Pt0.1/PNC NSs exhibits apparent hydrogen oxidation activity and durability with a record-high mass specific kinetic current of 1.84 A mg-1 at the overpotential of 50 mV, which is approximately 11.5 times higher than that of the Pt benchmark. Both experimental and theoretical studies reveal that the addition of Pt engenders a phase transition in CoRu alloys from hexagonal close-packed (hcp) to face-centered cubic (fcc) structure. The elevated reactivity of the resulted ternary alloy can be attributed to the optimized ad-sorption of hydrogen intermediate and the decreased reaction barrier for water formation. This study opens a new avenue for the development of highly efficient alloy NPs with various compositions and functions.

Amorphous Sn modified nitrogen-doped porous carbon nanosheets with rapid capacitive mechanism for high-capacity and fast-charging lithium-ion batteries

Amorphous Sn modified nitrogen-doped porous carbon nanosheets with rapid capacitive mechanism for high-capacity and fast-charging lithium-ion batteries

Three-dimensional porous nitrogen-doped carbon nanosheets with ultra-high surface area for high-performance oxygen reduction reaction electrocatalysts

A series of three-dimensional (3D) porous nitrogen-doped carbon nanosheets (PNCNs) have been successfully fabricated via a high-pressure carbonization followed by high-temperature thermal treatment. With the prolonging of thermal treatment time, the 3D PNCNs demonstrate several remarkable advantages for oxygen reduction reaction (ORR) electrocatalysts, including ultra-high specific surface area (more than 2100 m2/g−1), unique 3D porous structure, abundant defects, and suitable configuration of nitrogen. With these merits, the N-C-2 h based electrocatalyst exhibits outstanding ORR activities with a comparable onset potential of −40 mV (vs. Ag/AgCl), half-wave potential of −120 mV (vs. Ag/AgCl), satisfactory electron transfer number (4) and superior stability to those of commercial 20% Pt/C. The excellent electrochemical behaviors of 3D PNCNs are confirmed to be dominated by structural characteristics, which can be optimized by varying thermal treatment time. Our work offers a promising way for controllably constructing carbon-based materials with optimized ORR performance.

(FeSe2 + CoSe2) Nanoparticles Anchored on 3D Porous Ultrathin Carbon Nanosheets for High-Activity Oxygen Evolution Reaction

Since the sluggish kinetics of the oxygen evolution process (OER) at the anode of water splitting remains to be a crucial bottleneck for hydrogen production, it is imperative to develop low-cost OER electrocatalysts with high efficiency. Here, (FeSe2 + CoSe2) nanoparticles loaded on nitrogen-doped three-dimensional porous carbon nanosheets (referred to as (FeSe2 + CoSe2)/N-3DCN) were prepared by freeze-drying, heat treatment and selenization. The favorable affinity and large surface area of N-3DCN enabled the synthesis of the ultrafine (FeSe2 + CoSe2) nanoparticles with a diameter of 10 nm, which were highly dispersed on carbon nanosheets and provided a significant number of active sites. The density functional theory (DFT) calculation demonstrated that the free energy of oxygen-containing intermediates during OER was optimized by coupling FeSe2 with CoSe2. The overpotential of (FeSe2 + CoSe2)/N-3DCN is 312 mV at 10 mA cm–2, which is superior to those of (FeSe2 + CoSe2) (390 mV), CoSe2/N-3DCN (377 mV), RuO2 (320 mV), and FeSe2/N-3DCN (479 mV). Additionally, after the 80 h stability test, the overpotential of (FeSe2 + CoSe2)/N-3DCN can still be maintained at 316 mV.

Green preparation of flake nano porous carbon: For sulfur scaffolds in high-performance lithium sulfur batteries

In this report, we describe the creation of 2D porous nitrogen-doped carbon nanosheets using carbon precursors derived from silkworm cocoon biomass and CaCl2, a non-toxic and environmentally friendly material. The resulting carbon material exhibits a unique structure of nitrogen-doped nanosheets, extensive pore structure, and a significant specific surface area of 675 m2 g−1, which is attributed to the effect of Ca2+ on the structural conformation of silk glue protein. The high nitrogen doping, thin carbon sheets, and dense pore structure of the electrode material contribute to its excellent electrochemical performance. When used in a lithium‑sulfur composite electrode, it demonstrates exceptional electrochemical properties, including a very high initial capacity of 1403 mAh g−1, good multiplicity performance, and excellent cycling performance (700 mAh g−1 after 100 cycles at 0.1 C, 319 mAh g−1 after 1000 cycles at 1 C, and a capacity decay rate of 0.07 % per cycle). Importantly, the preparation strategy avoids the use of strong acid and alkaline structural restructuring agents, and provides an effective and green way to prepare advanced porous carbon electrode materials for lithium‑sulfur batteries.

Molten salt induced formation of chitosan based carbon nanosheets decorated with CoNx for boosting rechargeable Zn-air batteries

The earth-abundant, low-cost, and efficient oxygen electrode materials offer a potential opportunity to satisfy the large-scale production and application of metal-air batteries. Herein, a molten salt-assisted strategy is developed to anchor transition metal-based active sites via in-situ confining into porous carbon nanosheet. As a result, a chitosan-based porous nitrogen-doped nanosheet decorated with the well-defined CoNx (CoNx/CPCN) was reported. Both structural characterization and electrocatalytic mechanisms demonstrate a prominent synergetic effect between CoNx and porous nitrogen-doped carbon nanosheets forcefully accelerates the sluggish reaction kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Interestingly, the Zn-air batteries (ZABs) equipped with CoNx/CPCN-900 as an air electrode shows outstanding durability for 750 discharge/charge cycles, a high power density of 189.9 mW cm−2, and a high gravimetric energy density of 1018.7 mWh g−1 at 10 mA cm−2. Furthermore, the assembled all-solid cell displays exceptional flexibility and power density (122.2 mW cm−2).

Extrusion plant microtube synthesis of micron-sized nitrogen-doped hollow porous carbon nanosheets for high rate and high energy density supercapacitors

Extrusion plant microtube synthesis of micron-sized nitrogen-doped hollow porous carbon nanosheets for high rate and high energy density supercapacitors

Associating Co single atoms with RuO2nanoparticles anchor on nitrogen-doped ultrathin porous carbon nanosheets as effective bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries

The picture shows Co single atom-decorated RuO2nanoparticles anchored on nitrogen-doped ultrathin carbon nanosheet (CoSA-RuO2-NUCN). The bifunctional catalytic process (ORR/OER) of CoSA-RuO2-NUCN is also fully presented.

Facile synthesis of crumpled nitrogen-doped porous carbon nanosheets with ultrahigh surface area for high-performance supercapacitors.

Porous carbon nanosheets are currently considered excellent electrode materials for high-performance supercapacitors. However, their ease of agglomeration and stacking nature reduce the available surface area and limit the electrolyte ion diffusion and transport, thereby leading to low capacitance and poor rate capability. To solve these problems, we report an adenosine blowing and KOH activation combination strategy to prepare crumpled nitrogen-doped porous carbon nanosheets (CNPCNS), which exhibit much higher specific capacitance and rate capability compared to flat microporous carbon nanosheets. The method is simple and capable of one-step scalable production of CNPCNS with ultrathin crumpled nanosheets, ultrahigh specific surface area (SSA), microporous and mesoporous structure and high heteroatom content. The optimized CNPCNS-800 with a thickness of 1.59 nm has an ultrahigh SSA of 2756 m2 g-1, high mesoporosity of 62.9% and high heteroatom content (2.6 at% for N, 5.4 at% for O). Consequently, CNPCNS-800 presents an excellent capacitance, high rate capability and long cycling stability both in 6 M KOH and EMIMBF4. More importantly, the energy density of the CNPCNS-800-based supercapacitor in EMIMBF4 can reach up to 94.9 W h kg-1 at 875 W kg-1 and is still 61.2 W h kg-1 at 35 kW kg-1.

SnS2/ZIF-8 Derived Two-dimensional Porous Nitrogen-doped Carbon Nanosheets for Lithium-sulfur Batteries

SnS₂/ZIF-8 Derived Two-dimensional Porous Nitrogen-doped Carbon Nanosheets for Lithium-sulfur Batteries

Hierarchical porous nitrogen-doped carbon nanosheets derived from zinc-based bioMOF as flexible supercapacitor electrode

We propose an efficient and flexible supercapacitor electrode material based on hierarchically structured nitrogen-doped graphene-like carbon nanosheets (H-NCNs) with accordion-like shape. H-NCNs were obtained by pyrolyzing zinc-based biometal–organic frameworks (Zn-bioMOFs) and using urea as nitrogen source at high temperature (800 °C) under nitrogen atmosphere, and Zn-bioMOFs were synthesized using biomass molecules, i.e., curcumin. Inheriting from the features of Zn-bioMOF, H-NCNs showed hierarchical structures and unique accordion-like morphology. By changing the urea dosage, the nitrogen-doping degree and porosity of H-NCNs were regulated, optimizing the supercapacitive performance. H-NCNs-8 prepared with Zn-bioMOF/urea mass ratio of 1:8 exhibited high specific capacitance and superior rate capability (293 F g−1 at 0.25 A g−1 and 188 F g−1 at 50 A g−1). The H-NCNs-assembled symmetric supercapacitor offered long cycle life of over 40,000 cycles at 2 A/g and high energy density of 17.6 Wh kg−1 at 250 W kg−1, outperforming most carbon nanomaterial-related ones. Accordingly, the proposed flexible interdigital solid microsupercapacitor demonstrated high areal capacitance, high areal energy densities, and long cycle stability. The present work can provide promising application prospects of MOFs in the field of supercapacitors and flexible electronics.

Catalytic Oxidation of Glycerol over Pt Supported on MOF-Derived Carbon Nanosheets.

A series of nitrogen-doped porous carbon nanosheets (NPCNs) doped with transition-metal-supported Pt catalysts were prepared by colloidal deposition and evaluated for the selective oxidation of glycerol to glyceric acid (GLYA) under nonalkaline conditions. The transition metal contained in the catalyst was found to affect its performance and selectivity for GLYA, with the Pt/Zr@NPCN catalyst showing the highest catalytic activity and selectivity. These materials were characterized using Brunauer-Emmett-Teller surface area analysis, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and CO2 temperature-programmed desorption. The results showed that the small size of the Pt nanoparticles, the interaction between the Pt nanoparticles and the support, and the unique textural properties of the catalyst all promoted glycerol conversion and GLYA selectivity. A Zr concentration of 1.5 wt % and a support preparation temperature of 800 °C were found to provide a catalyst with the optimal performance that exhibited a glycerol conversion and selectivity for GLYA of 68.62 and 77.29%, respectively, at an initial O2 pressure of 10 bar and 60 °C after 6 h. Even after being recycled five times, this material provided a GLYA selectivity of approximately 75%, although the glycerol conversion decreased from 68 to 50%. The insights may provide new suggestions on the design of efficient support for the selective oxidation of polyols.