Abstract The development of sustainable nonwovens requires materials that not only originate from renewable resources but can also be repeatedly recovered, regenerated, and reused. In this study, hemp-derived cellulose nanofibrils (HNFs) were used as a renewable structural binder for nonwovens made from short cotton fibers to develop a reconfigurable fiber network capable of repeated deconstruction and reconstruction. Response surface modeling was used to optimize cotton fiber length, cotton content, and HNF loading to achieve a balance between breaking force and water absorbency comparable to a commercial cotton cosmetic pad. The optimum formulation consisted of 4 mm cotton fibers, 2.4 g fiber content, and 146 mg HNF loading, yielding a breaking force of ∼0.96 N and a water absorbency of 12.2 g/g. Structural analyses revealed that HNF loading was the primary factor dominating network consolidation, increasing fiber–fiber interactions, bulk density, and breaking force while reducing porosity and water absorbency. Repeated deconstruction–reconstruction cycles gradually decreased breaking force and increased water absorbency, accompanied by small but cumulative material losses during processing. The addition of 30 mg HNF during each reconstruction cycle maintained around 97–99% of the original breaking force and water absorbency over four regeneration cycles despite ongoing material losses. These findings show that targeted replenishment of HNF binder can restore the material properties of reconstructed cellulose fiber networks without replacing the entire material.
Abstract Coal-based hard carbon is a low-cost and industrially promising anode material for sodium-ion batteries (SIBs), yet the highly ordered structure generated from coal precursors after high-temperature carbonization severely degrades its electrochemical performance. Herein, an efficient microstructure modulation strategy is developed to restrict the formation of ordered carbon domains. Using high-fixed-carbon anthracite as the raw material, the Boudouard reaction is adopted to etch the carbon framework, creating abundant defects and nanopores. This approach inhibits microcrystal growth, enlarges interlayer spacing, induces more pseudo-graphitic structures, and optimizes nanopore distribution. The optimized THCO2-1300 electrode balances slope and plateau capacities, delivering a remarkable reversible capacity of 285.8 mAh g–1 at 25 mA g–1 and a high initial Coulombic efficiency of 73.9%. Furthermore, the assembled Na3V2(PO4)2O2F//THCO2-1300 full cell can still achieve a high energy density of 195.2 Wh kg–1 even at the highest power density of 8740.4 W kg–1. This work provides new insights into the microstructure regulation of coal-based hard carbon materials, which is expected to accelerate the practical application of low-cost, high-performance hard carbon in advanced SIBs.
Abstract Spent V-Ti-based selective catalytic reduction (SCR) denitrification catalysts are classified as hazardous solid wastes containing critical vanadium (V), molybdenum (Mo), and tungsten (W). However, traditional separation and recovery strategies require massive acid inputs and complicated multistep operations, restricting environmentally friendly industrial application. Herein, this work reports a one-pot integrated single-stage coextraction and costripping method to efficiently recycle V, Mo, and W from alkaline leachate of waste SCR catalysts. Preacidified primary amine N1923 achieves simultaneous extraction of three target metals, and subsequent ammonia stripping generates corresponding ammonium oxyacid solutions. Under optimal operational conditions, single-cycle total recoveries reach 94.96% for V, 83.50% for Mo, and 91.53% for W. The stripping liquor together with leaching residues can be applied to synthesize fresh SCR catalysts via impregnation with denitrification efficiency exceeding 92%, forming a renewable regeneration route. Saturation loading tests, slope analysis, and spectroscopic characterizations confirm an anion-exchange extraction mechanism. With reduced acid consumption and high metal recovery efficiencies, this approach provides a sustainable pathway for resource valorization of spent SCR catalysts.
Abstract Electrochemical synthesis offers a safe and sustainable route for synthesizing energetic materials (EMs). This work presents a green electrosynthetic strategy for 5,5′-azotetrazolate (ZT) by leveraging the low oxidation potential of 5-amino-1H-tetrazole (5-AT) in a coupled electrolysis system for energy-efficient hydrogen production. Anodic potassium 5,5′- azotetrazolate (PZT) synthesis is achieved using a CF@CuO catalyst, while cathodic hydrogen evolution is facilitated by a CC@VS2/Ru nanoparticle composite. The integrated system requires only 1.36 V to deliver 10 mA cm–2, which is 190 mV lower than that of conventional overall water splitting. The coupling strategy circumvents the use of strong oxidants and by-product formation inherent to traditional PZT synthesis, and the integrated electrolyzer exhibits stable continuous operation for over 50 h, while the CF@CuO anode maintains high 5-ATOR activity during a cumulative 300 h reusability test. Mechanistic investigations reveal that on the cathode side, Ru modification modulates the electronic structure of VS2, optimizing hydrogen adsorption free energy and accelerating water dissociation kinetics for enhanced alkaline HER. On the anode side, CuO catalyzes the 5-AT oxidation reaction (5-ATOR) via the OH*-mediated pathway, where continuous electron injection weakens N–H bonds and facilitates dehydrogenation coupling, significantly lowering the reaction energy barrier. This work establishes a dual-functional electrochemical platform integrating safe energetic materials synthesis with energy-saving hydrogen production.
Abstract Biomass-derived hard carbon is considered a promising anode material for sodium-ion batteries (SIBs) because of its low cost, sustainability, and tunable microstructure. However, the efficient construction of closed pores for sodium storage remains a major challenge. Herein, a simple and efficient strategy based on lignin-based phenolic resin adhesive (LPRA) crosslinking is proposed to induce open-to-closed pore conversion in biomass-derived hard carbon. During curing and subsequent pyrolysis at 1500 °C, the LPRA-derived crosslinked network promotes pore sealing and pore fusion, leading to the in situ formation of abundant closed pores within activated carbon frameworks and providing sufficient sodium-storage space. Structural characterization demonstrates that open pores with sizes of 1.23 and 1.14 nm are extensively converted into closed pores after LPRA incorporation and high-temperature carbonization. Benefiting from the engineered closed-pore architecture, the optimized sample (ACPC-2) exhibits markedly enhanced electrochemical performance. The capacity reaches 2.32 times that of ACC-2, while the initial coulombic efficiency increases to 89.85%. In addition, a high capacity retention of 93.49% is maintained after 100 cycles at 300 mA g–1. Combined in situ and ex situ characterizations further reveal distinct sodium-storage behaviors in hard carbons with different pore structures. In particular, ACPC-2 predominantly stores sodium through sodium-cluster filling within closed pores, which contributes dominantly to the capacity. This work provides a low-cost and sustainable strategy for converting biomass-derived carbon into high-value closed-pore hard carbon and offers useful insights into pore evolution and sodium-storage behavior for the development of high-performance SIB anodes.
