Carbon Letters最新文献

Combining CuPc with semiconductor materials as organic‒inorganic hybrid photocatalysts can effectively improve the light absorption capacity and separation efficiency of photogenerated electrons and holes in semiconductor photocatalysts. Herein, a CuPc/Bi₂WO₆ Z-scheme heterojunction was successfully designed and used for CO₂ photoreduction. The separation of photogenerated electrons and holes is greatly enhanced because of the formation of a compact organic‒inorganic heterointerface and the built-in electric field between CuPc and Bi₂WO₆, which increases the photocatalytic CO₂ reduction efficiency. Moreover, the photosensitizer CuPc can effectively enhance the light absorption of Bi₂WO₆. The optimal 1CuPc/Bi₂WO₆ composite exhibits the best photocatalytic performance, with a CO production rate of 2.95 µmol g^−l h⁻¹, which is three times greater than that of Bi₂WO₆ under visible-light irradiation. This work provides a new idea for the construction of an organic‒inorganic photocatalytic system for CO₂ reduction.

Designing long-wavelength emissive carbon dots (CDs) with high photoluminescence quantum yield (PL QY) is an inevitable component for lighting applications. However, it is still challenging to develop an efficient CDs with excitation-independent emission in long-wavelength regions. In this work, we developed an excitation-independent yellow emissive CD (y-CDs) with PL emission centered at 568 nm via a facile solvothermal treatment of citric acid and melamine using toluene as solvent. The synthesized, y-CDs contain a high degree of conjugated sp²-carbon domains (fused rings) with different surface groups, which serve as a center for photon absorption. The addition of melamine improves the degree of sp²-conjugated carbon domain and surface groups thereby switching the emission of y-CDs from excitation-dependent to excitation-independent emission with excellent PL QY of 80.2%, UV stability, and large Stoke shift. This work not only developed an efficient yellow emissive CD but also explored the possible mechanism of excitation-independent emission and used it for the development of phosphor-converted LEDs. The LED shows warm yellow light with CIE coordinates of (0.48, 0.49), CCT of 2983 K, excellent color purity of 94%, and high thermal stability. This study promotes the development of cost-effective and eco-friendly optoelectronic devices for smooth lighting applications.

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Photocatalytic reduction of CO₂ into fuels offers a promising avenue to tackle present energy challenges and mitigate global warming. At present, TiO₂ has been widely used in photocatalytic CO₂ reduction reactions, and element doping can optimize the band structure of TiO₂ to improve the efficiency of photocatalytic CO₂ reduction. In this work, TiO₂ doped with different content of N was prepared using TiN as the precursor through a simple one-step calcination method. Under optimized conditions, the optimal CO yield of the modified photocatalyst is 41.1 μmol g⁻¹ h⁻¹, which is 8 times higher than that of p25 type TiO₂. Density functional theory (DFT) calculations confirmed that N-doping can reduce the band gap of TiO₂ and decrease the Gibbs free energy of CO₂ reduction reaction. In-situ-XPS indicated that N-doping can enhance the activation of CO₂ by enriching photo generated electrons. Additionally, In-situ-FTIR spectra were employed to detect intermediates and track variations in the consumption of H₂O and CO₂, providing deeper insights into the mechanism responsible for enhancing efficiency. Our work addresses the deficiencies of the past and provides more detailed theoretical insights for the accelerated photocatalytic reduction of CO₂ by N-doping TiO₂.

The composite of CVD-grown Gr is a promising method for improving the electrical properties of Cu-based microscale materials. Almost all of the previous works focused on the CVD-grown continuous Gr. However, after the combination with surface of Cu substrate, the continuous Gr is prone to fracture or peeling when it is bent under strain in practical applications with low bending stability, leading to a decrease in its conductivity. In this study, significantly enhanced electrical properties and bending stability are demonstrated by synthesizing CVD-grown Gr sheets layers on microscale-diameter Cu wires, including 10.9% higher electrical conductivity and 7.9% higher maximum current density compared to commercial pristine Cu wires. After the test of bending cycles, Gr sheets/Cu wires exhibit extraordinary bending stability, with less than 1.3% conductivity changes for wires. In contrast, the continuous Gr/Cu wires show poor bending stability with a nearly 10% reduction in conductivity. Hence, the Gr sheets/Cu wires have significant advantages in practical applications.

A considerable amount of the food is wasted each year, creating an urgent global problem with negative economic and environmental effects. Livestock manure, a by-product of intensive animal farming, can contribute to environmental issues if not properly managed. While biochar, a product of pyrolysis, can speed up the composting process and improve compost quality, sawdust is frequently used in composting to balance the carbon-to-nitrogen ratio. This study aimed to investigate the effects of biochar on compost quality in co-composting food waste and swine manure and the influence of raw materials in obtaining good quality ecofriendly compost. Experimental manipulations were conducted both with feedstock materials present and absent. The findings revealed that a biochar concentration of 6% had a positive impact on the composting process. Furthermore, the presence or absence of feedstocks influenced the composting rate and the quality of the compost. Through the addition of biochar, moisture balance and porosity were improved, promoting the growth of beneficial microorganisms. Organic waste can be managed more sustainably and agricultural systems may be improved by keeping it out of landfills and composting it with biochar. According to this study, a proper balance of feedstock composition is equally important to the addition of biochar. The study contributes to the understanding of the composting process and the role of balancing feedstock components for the production of good quality compost.

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The adsorption of a single pollutant can no longer meet the increasingly strict requirements of environmental governance. The easy loss and secondary pollution of powdered adsorbents further hinder the industrialization of adsorption technology. Through in-situ oxidative polymerization and hydrothermal deposition, polyaniline (PANI) and magnetic Fe₃O₄ nanoparticles were loaded onto a polyurethane (PU) matrix to prepare polyurethane-polyaniline /Fe₃O₄ (PU-P/F) porous composite loading materials, aiming to simultaneously remove multiple pollutants in wastewater and solve the problem of effective solid–liquid separation at the same time. The synthesized composite material exhibited a high specific surface area (30.08 m²/g) and a hierarchical pore structure. Within a wide pH range (5–7), it showed a synchronous adsorption and removal effect on typical pollutants (ARG, Cr (VI), NO₃⁻-N, TP, MB, NH₄⁺-N) in printing and dyeing wastewater. Equilibrium can be reached within 0.5–2 h, following pseudo-second-order kinetics and Langmuir isotherm model, indicating mainly monolayer chemical adsorption. The continuous column adsorption regeneration test showed that for the simulated mixed wastewater, the continuous adsorption reached saturation after 660 min (53 chromatographic columns), while for the actual wastewater, the continuous column adsorption reached saturation after 535 min (43 chromatographic columns), and the efficiency remains after 8 regenerations. FT-IR and XPS confirmed the REDOX reaction between the –NH—group in polyaniline and Fe in Fe₃O₄, facilitating the adsorption and transformation of pollutants, while DFT calculations confirmed the strong interaction between polyaniline and anionic pollutants. This research provides ideas for solving the engineering bottleneck of adsorption technology.

Graphical abstract

Diagram of in-situ loading of Fe3O4 and PANI onto polyurethane.

CNT/epoxy composite film (CECF) was prepared and used to fabricate the interlayer stiffened and reinforced photothermal synergistic curing glass fiber-reinforced polymer (GFRP) composites, and the influence of the photothermal effects of CECF on compressive strength and failure mechanism of the composite was investigated. Compared to GFRP composite, the uniform and wide temperature distribution in the in-plane and thickness direction was exhibited due to the heat from the lattice vibrations induced by photothermal conversions of CECF, thereby facilitating the decomposition of the thermal initiator and the increase of the curing degree in the CECF/GFRP composite. The in-plane shear modulus and interlaminar shear strength (ILSS) of the CECF/GFRP composite were 12.2% and 13.7% higher than those of the GFRP composite, respectively, indicating the enhanced deformation resistance and interfacial adhesion of the interlayer region. The compressive strength of the CECF/GFRP composite was increased by 14.1% relative to the GFRP composite, which was ascribed to restricted kink-band and delayed delamination damage during the compression process of composite.

The environmental, social, and economic concerns regarding fossil fuels necessitate the demand for an efficient energy mix utilising renewable resources like biomass for sustainable development. Recent interest in the thermochemical conversion of coal and biomass into bioenergy via co-pyrolysis processes is gaining importance. This review critically assesses the behaviour of different types of coal and biomass blends during co-pyrolysis from various perspectives, including the effects of temperature, blending ratios, heating rate, synergistic and inhibitive behaviours, heat transfer mechanisms, nature of products, and their future applications. The possible synergies arising due to differences in the compositions of coal and biomass are discussed. In addition, the synergistic effect on co-pyrolysis yield is critically presented. Moreover, it is analysed that the co-pyrolysis offers higher yields of liquid and gaseous fuels compared to individual feedstock coal and biomass. Co-pyrolysis of coal and biomass can be promoted from a scientific standpoint; however, further research is still required for the integration of new technologies to enhance the effectiveness of co-pyrolysis.

Chemical activation consumes copious quantities of chemicals is therefore hampered by its low economic feasibility. However, this issue can be overcome through the recovery and reuse of alkali compounds leached into wastewater. Because the leached potassium compounds exist as the relatively less reactive K₂CO₃, we explored three different approaches to remove carbonate ions (CO₃²⁻) from the wastewater: (i) CO₂ stripping after acidification, (ii) exchanging CO₃²⁻ for OH⁻ using strong basic anion exchange resins, and (iii) inducing a phase transition via a reaction with Ca(OH)₂ to precipitate CaCO₃. Both ion exchange and phase transition convert K₂CO₃ into highly reactive potassium compounds such as KOH. The phase transition effectively enhanced the specific surface area of the activated carbon and thus had implications for pore development in carbon precursors, while offering a viable recovery strategy for alkali compounds that reduces costs by approximately 20% compared to traditional methods. These findings suggest that the in-situ recycling of wastewater for the production of activated carbon can improve the economic viability of manufacturing processes.

Porous carbon derived from biomass represents pivotal electrode materials for electric double-layer capacitors (EDLCs). However, their applications are limited by the low pore utilization and low withstanding voltage (< 2.7 V), which largely hinder the energy density (E_g) of SCs. In this study, fulvic acid-derived porous carbons (FPs) were synthesized through the self-assembly and KOH activation strategy by employing fulvic acid (FA) as the precursor and cationic surfactant PDDA as the soft template. The electrostatic forces between FA and PDDA enable the structural orientation of FA, leading to the formation of stable layered liquid microcrystals. Besides, under the activation process, the decomposition of PDDA contributes to the interconnected pores in FPs. Thus, the obtained sample FP1 exhibits a high specific surface area (2593 m² g⁻¹) and high mesopore ratio (48%). Moreover, low oxygen content and stable surface composition promote the withstanding voltage of FPs. In the TEABF₄/PC electrolyte, the sample FP1 is capable of a high voltage of 3.0 V, high-rate capability C_10/0.05 of 76.3%, and high energy density of 39 Wh kg⁻¹.