Search Results (226)

Porous highly cross-linked polymer (PIP) was synthesized by a polycondensation reaction between hexachlorocyclotriphosphazene and piperazine. The obtained polymer has a surface area of 76.9 m²/g and a mesoporous structure. After carbonization, the obtained product (PIP-C) has a surface area of 177 m²/g. The obtained carbon product contained nitrogen and phosphorus heteroatoms, which leads to a higher specific capacitance (155.6 F/g) and catalytical activity in the electroreduction of oxygen (15.9 A/g). This work shows the possibility of the use of such porous phosphazene polymers as precursors for heteroatom-doped carbon materials, which might be used in electrochemical devices like electrodes for supercapacitors or metal-free electrocatalysts in fuel cells. Full article

This study presents a straightforward strategy for producing novel, effective and inexpensive functional non-noble metal-supported carbon materials made from abundant natural biomass. These materials offer a cost-effective alternative to noble metals for the oxidation of hydrazine (HzOR) and demonstrate the potential for widespread adoption of green, energy-saving hydrazine-based technologies in energy applications. Highly efficient and cost-effective iron (Fe) and manganese–iron (MnFe)-supported nitrogen-doped carbon (N–C) materials were developed using hydrothermal synthesis. Meanwhile, the N–C material was obtained from biomass—birch-wood chips—using hydrothermal carbonisation (HTC), followed by activation and nitrogen doping of the resulting hydrochar. The morphology, structure, and composition of the MnFe, MnFe/N–C, and Fe/N–C catalysts were determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS). The activity of the catalysts for HzOR in an alkaline medium was evaluated using cyclic voltammetry (CV). Depositing MnFe particles onto N–C was shown to significantly enhance electrocatalytic activity for HzOR compared to the Fe/N–C catalyst and especially to the MnFe particles catalyst in terms of highly developed porous structure, which offers the largest surface area, lowest onset potential, and highest current density response, resulting in the strongest catalytic activity. These results suggest that the MnFe/N–C catalyst could be a highly promising anode material for HzOR in direct hydrazine fuel cells (DHFCs). Full article

This study presents the development of a smart packaging material utilizing garlic-derived nitrogen-doped carbon dots (CDs) integrated into a whey protein–starch (WP-S) emulsion. The research aimed to create a real-time, non-invasive biosensor capable of detecting microbial spoilage. The synthesized CDs demonstrated strong pH-sensitive photoluminescence, exhibiting distinct changes in CIE coordinates and fluorescence intensity in response to varying pH values. The WP-S-CDs emulsion was tested against E. coli, S. aureus, and C. albicans. The results showed that the composite film provided a clear colorimetric shift and fluorescence quenching, both of which are directly correlated with microbial metabolic activity. The physical and electronic properties of the composite were investigated to understand the sensing mechanism. Scanning electron microscopy (SEM) of the dried film revealed that the WP-S-CDs system formed a more porous structure with larger pore sizes (3.63–8.18 µm) compared to the control WP-S film (1.62–6.52 µm), which facilitated the rapid diffusion of microbial metabolites. Additionally, density functional theory (DFT) calculations demonstrated that the incorporation of CDs significantly enhanced the composite’s electronic properties by reducing its band gap and increasing its dipole moment, thereby heightening its reactivity and sensitivity to spoilage byproducts. In a practical application on apples, the WP-S-CDs coating produced a visible red spot, confirming its function as a dynamic sensor. The material also showed a dual-action antimicrobial effect, synergistically inhibiting C. albicans while exhibiting an antagonistic effect against bacteria. These findings validate the potential of the WP-S-CDs emulsion as a powerful, multi-faceted intelligent packaging system for food quality monitoring. Full article

Chitin-derived biomass carbon materials are promising supercapacitor electrode materials due to their wide availability, low cost, high specific surface area, and nitrogen doping capability. However, their practical application is limited by insufficient conductivity and cyclic stability, often requiring functional modification or integration with complementary materials. In this study, we present a novel strategy by incorporating copper sulfide (Cu₂S) into a chitin-based carbon matrix. Cu₂S, known for its high intrinsic conductivity, excellent electroactivity, and theoretical specific capacity (~335 mAh·g⁻¹), was uniformly doped into the three-dimensional carbon aerogel framework derived from chitin nanofibers (ChNF) through sol–gel, freeze-drying, and high-temperature carbonization processes. The resulting chitin-based carbon/Cu₂S composite aerogel (CChNF/Cu₂S) exhibited a hierarchical porous structure with Cu₂S nanoparticles (20–30 nm) uniformly distributed on the carbon fiber surface. Electrochemical tests demonstrated its excellent performance, achieving a specific capacitance of 852 F·g⁻¹ at 1 A·g⁻¹, highlighting the synergistic effects of the conductive Cu₂S and nitrogen-doped carbon framework for high-performance supercapacitor applications. Full article

Carbon dioxide emissions, particularly from large point sources such as fossil-fuel power plants, represent a primary driver of global warming. Although various carbon-based adsorbents have been developed for carbon capture applications, most existing materials exhibit limited CO₂ adsorption capacity at flue gas-relevant partial pressures and are susceptible to interference from impurity components. In this study, a series of nitrogen-doped carbons was prepared from commercial phenolic resin and melamine via a two-step carbonization–activation process. The effects of precursor-to-dopant ratio and thermal conditions on CO₂ adsorption were systematically investigated. The results indicated that CO₂ uptake was influenced by specific surface area, nitrogen content, micropore volume, and total pore volume, with a maximum adsorption capacity of 2.455 mmol·g⁻¹ and selectivity over 28 at 25 °C and 1 bar. The series also exhibited excellent cycling stability (<1% loss after 5 cycles) and fast kinetics (>90% uptake within 3 min), suggesting its potential applicability in flue gas CO₂ capture. Full article

Developing sustainable and high-performance sorbents for efficient CO₂ capture is essential for mitigating climate change and reducing industrial emissions. In this study, phosphorus-doped porous carbons (LPSP-T) were synthesized via a one-step activation–doping strategy using lotus petiole biomass as a precursor and sodium phytate as a dual-function activating and phosphorus-doping agent. The simultaneous activation and phosphorus incorporation at various temperatures (650–850 °C) under a nitrogen atmosphere produced carbons with tailored textural properties and surface functionalities. Among them, LPSP-700 exhibited the highest specific surface area (525 m²/g) and a hierarchical porous structure, with abundant narrow micropores (<1 nm) and phosphorus-containing surface groups that synergistically enhanced CO₂ capture performance. The introduction of P functionalities not only improved the surface polarity and binding affinity toward CO₂ but also promoted the formation of a well-connected pore network. As a result, LPSP-700 delivered a CO₂ uptake of 2.51 mmol/g at 25 °C and 1 bar (3.34 mmol/g at 0 °C), along with a high CO₂/N₂ selectivity, fast CO₂ adsorption kinetics and moderate isosteric heat of adsorption (Q_st). Furthermore, the dynamic CO₂ adsorption capacity (0.81 mmol/g) was validated by breakthrough experiments, and cyclic adsorption–desorption tests revealed excellent stability with negligible loss in performance over five cycles. Correlation analysis revealed pores < 2.02 nm as the dominant contributors to CO₂ uptake. Overall, this work highlights sodium phytate as an effective dual-role agent for simultaneous activation and phosphorus doping and validates LPSP-700 as a sustainable and high-performance sorbent for CO₂ capture under post-combustion conditions. Full article

Lithium-oxygen batteries (LOBs) are limited by sluggish oxygen redox kinetics and cathode instability. Herein, we report a cobalt particle catalyst encapsulated in nitrogen-doped carbon (Co@NC) with a three-dimensional hierarchical architecture, synthesized via a chitosan-derived hierarchical porous carbon framework. This innovative design integrates uniformly dispersed ultra-thin carbon shells (11.7 nm), pyridinic nitrogen doping, and Co particles (1.41 μm) stabilized through carbon-support electronic coupling. The hierarchical porosity facilitates rapid O₂/Li⁺ mass transport, while pyridinic N sites act as dual-function electrocatalytic centers for Li₂O₂ nucleation and charge transfer kinetics. Co@NC achieves 11,213 mAh g⁻¹ at 200 mA g⁻¹ (126.5% higher than nitrogen-doped carbon) and maintains 1.54 V overpotential (500 mAh g⁻¹). These metrics outperform benchmark catalysts, addressing kinetic and stability challenges in LOBs. The study advances electrocatalyst design by integrating structural optimization, heteroatom doping, and electronic coupling strategies for high-performance metal–air batteries. Full article

Polybenzoxazines (PBZs) have garnered significant attention as a versatile class of precursors for the development of advanced carbon-based materials, particularly in the field of electrochemical energy storage. This review comprehensively examines recent progress in the synthesis, structural design, and application of polybenzoxazine-derived materials for supercapacitor electrodes. Owing to their intrinsic nitrogen content, tunable functionality, and excellent thermal and mechanical stability, polybenzoxazines serve as ideal precursors for producing nitrogen-doped porous carbons with high surface areas and desirable electrochemical properties. This review discusses the influence of molecular design, polymerization conditions, and carbonization parameters on the resulting microstructure and performance of the materials. Furthermore, the electrochemical behavior of these materials in both electric double-layer capacitors (EDLCs) and pseudocapacitors is analyzed in detail. Challenges such as optimizing pore architecture, improving conductivity, and achieving scalable synthesis are also addressed. This article highlights emerging trends and offers perspectives on the future development of polybenzoxazine-derived materials for next-generation high-performance supercapacitors. Full article

The photocatalytic reduction of hexavalent chromium (Cr(VI)) in wastewater represents a critical environmental challenge, given its high toxicity and mobility in wastewater. Conventional optimization methods relying on repetitive batch experiments with excessive reagent consumption. Herein, we proposed a synergistic experimental–deep learning approach to realize efficient photocatalytic reduction of Cr(VI). Sludge and cellulose precursors were used to prepare N-doped porous carbon through a green fabrication method at low temperature. After optimizing the composition and experimental factors, the removal efficiency of Cr(VI) could reach 92.7% after visible light irradiation in an acidic environment. The high efficiency originated from the coupled adsorption and photocatalytic mechanism. Innovatively, after comparing three algorithms, TCN and Transformer were employed to predict the desirable removal efficiency with <5% prediction error under different reaction conditions. This work highlights the novel experimental–deep learning method for heavy metal remediation using N-doped waste-derived porous carbon. Full article

The hierarchical porosity and active sites of porous carbon materials have significant impacts on the oxygen reduction reaction (ORR) process. The heteroatom-doped porous carbon materials (Z67-900, Z8-900, Z11-900, Z12-900) were synthesized by pyrolysis of ZIFs to reveal the synergistic effect of hierarchical porosity and Co-N_x sites. The structures of prepared materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and nitrogen adsorption. The results of electrocatalytic performance show that Z67-900 has the best performance among the four materials prepared. The onset potential (E₀) of Z67-900 is close to commercial Pt/C (20%), and the half-wave potential (E_1/2) of Z67-900 is 80 mV positive than that of Pt/C in an O₂-saturated 0.1 M KOH solution (1600 rpm) with sweep rate of 5 mV·s⁻¹. Moreover, Z67-900 has better methanol resistance. The hierarchical pore structure of Z67-900 facilitates mass transfer, while the Co-N_x sites provide active catalytic centers. This study provides a solid foundation for the rational design of highly efficient ZIF-derived heteroatom-doped catalysts. Full article

The development of heterogeneous nanocatalysts with high performance is essential for improving hydrogen production through formic acid dehydrogenation, but challenging. Herein, highly dispersed Pd nanoparticles (NPs) were successfully immobilized on porous nitrogen-doped carbon cages (PNCCs) derived from zeolitic imidazole frameworks. By virtue of the synergistic effect, the optimized Pd/PNCC nanocatalytic systems exhibit an excellent catalytic kinetics toward catalyzing FA dehydrogenation with a turnover frequency (TOF) value as high as 3174 h⁻¹ at 323 K, which is 59 times relative to that of Pd nanoparticles. The exceptional activity may be ascribed to the PNCC solid support may induce a strong electronic metal–support interaction to optimize the electron configuration of Pd active sites and accelerate the kinetics of O-H bond cleavage, resulting in an enhanced catalytic performance toward FA dehydrogenation. This work will supply a novel strategy for the development of supported nanocatalysts with high performance for tremendous catalytic applications in the future. Full article

Direct Air Capture (DAC) is gaining worldwide attention as a negative emissions strategy critical to meeting climate targets. Among emerging DAC materials, pyrolysis chars (PCs) and gasification chars (GCs) derived from biomass present a promising pathway due to their tunable porosity, surface chemistry, and low-cost feedstocks. This review critically examines the current state of research on the physicochemical properties of PCs and GCs relevant to CO₂ adsorption, including surface area, pore structure, surface functionality and aromaticity. Comparative analyses show that chemical activation, especially with KOH, can significantly improve CO₂ adsorption capacity, with some PCs achieving more than 308 mg/g (100 kPa CO₂, 25 °C). Additionally, nitrogen and sulfur doping further improves the affinity for CO₂ through increased surface basicity. GCs, although inherently more porous, often require additional modification to achieve a similar adsorption capacity. Importantly, the long-term stability and regeneration potential of these chars remain underexplored, but are essential for practical DAC applications and economic viability. The paper identifies critical research gaps related to material design and techno-economic feasibility. Future directions emphasize the need for integrated multiscale research that bridges material science, process optimization, and real-world DAC deployment. A synthesis of findings and a research outlook are provided to support the advancement of carbon-negative technologies using thermochemically derived biomass chars. Full article

Developing efficient and durable electrocatalysts for the alkaline hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production. Herein, we report a novel RuP₂/Mn₂P₂O₇ heterojunction anchored on a three-dimensional nitrogen and phosphorus co-doped porous carbon (RuP₂/Mn₂P₂O₇/NPC) framework as a high-performance HER catalyst, synthesized via a controlled pyrolysis–phosphidation strategy. The heterostructure achieves uniform dispersion of ultrafine RuP₂/Mn₂P₂O₇ heterojunctions with well-defined interfaces. Furthermore, phosphorus doping restructures the electronic configuration of Mn and Ru species at the RuP₂/Mn₂P₂O₇ heterointerface, enabling enhanced catalytic activity through the accelerated electron transfer and kinetics of the HER. This RuP₂/Mn₂P₂O₇/NPC catalyst exhibits exceptional HER activity with 1 M KOH, requiring only 69 mV of overpotential to deliver 10 mA·cm⁻² and displaying a small Tafel slope of 69 mV·dec⁻¹, rivaling commercial 20% Pt/C. Stability tests reveal negligible activity loss over 48 h, underscoring the robustness of the heterostructure. The RuP₂/Mn₂P₂O₇ heterojunction demonstrates markedly reduced overpotentials for the electrochemical HER process, highlighting its enhanced catalytic efficiency and improved cost-effectiveness compared to the conventional catalytic systems. This work establishes a strategy for designing a transition metal phosphide heterostructure through interfacial electronic modulation, offering broad implications for energy conversion technologies. Full article

Hydrogen energy as a sustainable alternative to fossil fuels necessitates the development of cost-effective and efficient electrocatalysts for the hydrogen evolution reaction (HER). While transition metal sulfides have shown promise, their practical application is hindered by insufficient active sites, poor conductivity, and suboptimal hydrogen adsorption kinetics. Herein, we present a heterointerface engineering strategy to construct Co₉S₈/FeCoS₂ heterojunctions anchored on bamboo fiber-derived nitrogen-doped porous carbon (Co₉S₈/FeCoS₂/BFPC) through hydrothermal synthesis and subsequent carbonization. BFPC carbon quasi-aerogel support not only offers a high surface area and conductive pathways but also enables uniform dispersion of active sites through nitrogen doping, which simultaneously optimizes electron transfer and mass transport. Experimental results demonstrate exceptional HER performance in alkaline media, achieving a low overpotential of 86.6 mV at 10 mA cm⁻², a Tafel slope of 68.87 mV dec⁻¹, and remarkable stability over 73 h of continuous operation. This work highlights the dual advantages of heterointerface design and carbon substrate functionalization, providing a scalable template for developing noble metal-free electrocatalysts for energy conversion technologies. Full article

This study developed a highly facile method to synthesize Zn-decorated and nitrogen-doped hierarchical porous carbons for carbon dioxide (CO₂) adsorption. Zeolitic imidazolate framework-8 (ZIF-8) was used as the raw material, which was subjected to a thermal treatment to obtain ZIF-8-derived carbons (ZDCs) in order to develop nanocarbons with a stable framework structure, a high CO₂ adsorption capacity, and high selectivity under normal pressure. The crystallinity evolution of the samples changed from the typical ZIF-8 structure to having features of graphite carbons upon heating. The average particle sizes of the products were between 34 and 105 nm, and the specific surface areas ranged from 618 to 1862 m²/g. The nitrogen and zinc contents gradually decreased with increasing carbonization temperatures, but the changes in the distributions of the functional groups were different. The interactions between CO₂ and the ZDCs were significantly enhanced, resulting in a higher isosteric heat of adsorption. The ZIF-8 carbonized at 1123 K exhibited the highest CO₂ uptake, i.e., 3.57 mmol/g at 298 K and 101.3 kPa, while higher CO₂ uptakes at 15 kPa occurred on the ZIF-8 carbonized at 923 and 1023 K due to their high isosteric heat of adsorption of CO₂. The higher adsorption selectivity of Z8-650 for CO₂ over N₂ may be due to its higher V_<0.7nm/V_mi ratio and nitrogen and zinc contents. Consequently, the micropore area ratio and surface functional groups primarily determined the CO₂ adsorption capacity at 15 kPa. In addition, an appropriate metal Zn to Zn²⁺ ratio may have a positive effect on CO₂ adsorption. On the other hand, the ultramicropore volume ratio, micropore volume ratio, micropore area, and SSA played more significant roles at 101.3 kPa of pressure. Full article