ChemSusChem最新文献

Lignin is an attractive feedstock for a wide variety of applications ranging from aromatic chemicals and transportation fuels to resins and coatings. Emerging biorefinery concepts, like the organosolv process, enable the separation of all the lignocellulose components, and moreover, produce lignins of high quality and purity susceptible to valorisation by depolymerisation. In this work, we focus on the depolymerisation of lignins obtained by γ-valerolactone (GVL) organosolv fractionation of four biomass feedstocks, eucalyptus, white birch, sugarcane bagasse and Scots pine. We demonstrate that lignins extracted with the GVL process are depolymerised using unsupported molybdenum-based catalysts under reductive conditions in supercritical ethanol. As a result, over 90% yields of low-molecular-weight lignin oils are obtained with minimal char formation, yields of the aromatic monomers being 7–16 wt%. Furthermore, the design of experiments method is used to analyse the effect of depolymerisation conditions, catalyst, hydrogen loading and temperature, on the yields and properties of the product fractions. Notably, we show that the properties of the lignin oils and monoaromatics can be tuned towards the targeted application by modifying the depolymerisation conditions.

In zero-gap saltwater electrolysis, ion transport is influenced by convective forces, but their effects have not been examined when using thin-film composite (TFC) membranes with advective flow through the membrane. In this study, we adapted a one-dimensional solution-friction transport model for a zero-gap electrolyzer to incorporate measured water flux across a TFC membrane. Open-circuit or electrolysis (20 mA cm^–2) experiments quantified ion transport with and without electrochemical reactions. Water velocity, estimated from volume changes in the anolyte and the catholyte, was used to infer convective contributions to ion transport. Ion-specific friction coefficients were determined using open-circuit data. Using the fitted friction factors and incorporating water flux, the modeled ion crossover concentration showed good agreement with electrolysis data, including changes caused by reversing the membrane orientation. Removing the convective flux from the model showed up to a 740% change in predicted ion crossover and worsened agreement with experimental data. The strong correlation between the fraction of charge carried by major salt ions and the measured water flux suggests that electroosmotic drag could be one of the main mechanisms responsible for the observed water flux. These results highlight the importance of incorporating solution convection when modeling ion behavior in zero-gap systems using TFC membranes.

Lignin (L)-stabilized emulsions have gained interest as sustainable systems. Despite their advantages, the interaction of lignin derivatives with oil and water in emulsion systems remains unclear. In this work, we verified a hypothesis that different modification strategies would generate lignin derivatives with different emulsifying performances, even if lignin is anionically charged to a similar degree. To verify this hypothesis, we generated sulfoethylated lignin (SL) and carboxyethylated lignin (CL) softwood kraft lignin (L) as functional emulsifiers for soybean water emulsion systems. It was observed that lignin derivatives with a more negative zeta potential (ζ-potential) and smaller oil particles resulted in more stable emulsions at alkaline pH due to enhanced electrostatic repulsion. Due to well-dispersed oil droplets and a strong electrostatic system, the viscosity of emulsions was lower at alkaline conditions. It was also noted that SL and CL generated Pickering emulsions via depositing on oil droplets and developing steric hindrance with oil droplet sizes of 436 and 452 nm at acidic pH. However, such systems had shorter lifespans under acidic environments, indirectly implying that steric hindrance was insufficient to generate emulsions with long-term stability. These findings verified the involvement of different mechanisms for stabilizing oil emulsions at various pH levels.

The properties of sulfur host materials are critical for mitigating the lithium polysulfide (LiPS) shuttle effect and prolonging the Li–S battery lifetime. Herein, we have developed a unique polyvinyl chloride (PVC)-derived polymeric host material (named as XC); results show that XC host is capable of achieving strong chemical/physical confinement to the encapsulated sulfur and lithium polysulfide (LiPS) intermediates, thus significantly reducing the shuttling effect and improving the battery cycle life to above 500 cycles with only 9.3% capacity loss (74.4% after 1000 cycles). While with increased S loading of 6.2 mg-S/cm² and electrolyte-to-sulfur ratio of 6 μL/mg-S, the XC/S28 composite comprising 20% XC and 80% S maintains 67.5% of its capacity at the 200^th cycle. Apart from the chemical immobilization of short-chain S_x (x = 2−4) in micropores or organic skeletons, the use of XC as a polymeric encapsulant still maintains the solid–liquid–solid conversion in highly solvating electrolytes, guaranteeing high discharge voltage and energy while significantly extending cycle life.

The development of low-cost, earth-abundant electrocatalysts is essential for advancing hydrogen-based energy technologies, yet conventional water splitting remains constrained by the sluggish oxygen evolution reaction (OER). Substituting OER with the urea oxidation reaction (UOR) offers a more favorable alternative, reducing the reaction potential while simultaneously addressing wastewater remediation. Herein, we develop a heterostructured electrocatalyst of amorphous FeOOH quantum dots (QDs) uniformly anchored on NiMn layered double hydroxide (LDH) nanosheets grown on nickel foam (NF). The ultrathin conductive NiMn-LDH scaffold offers high surface accessibility and tunable redox activity, while the FeOOH QDs introduce abundant active centers that accelerate charge transfer and optimize OH⁻ and urea adsorption. As a result, FeOOH QDs/NiMn-LDH/NF requires only a low overpotential of 1.42 V to reach 50 mA cm⁻² for OER and 1.33 V for UOR, with small Tafel slopes of 31 and 29 mV dec⁻¹ and exhibits outstanding long-term durability of 50 h. Moreover, the heterostructured electrocatalyst shows competent activity for the hydrogen evolution reaction (η₁₀ = 125 mV) and delivers an average Faradaic efficiency of ≈95.7% during electrolysis, confirming highly selective charge-to-hydrogen conversion. This enables efficient urea-assisted overall water electrolysis at only 1.44 V. This work underscores the synergistic integration of LDH nanosheets with amorphous QDs as a versatile and scalable strategy to engineer next-generation bifunctional electrocatalysts for energy-efficient hydrogen production coupled with wastewater treatment.

This work focuses on improving the sustainability of electrolytes for sodium-ion capacitors (SICs). Through the combination of a low-fluorinated salt, namely sodium difluoro(oxalato)borate (NaDFOB), and the bio-based solvent γ-Valerolactone (GVL), a new electrolyte formulation (1 mol L⁻¹ NaDFOB in GVL) is being studied for application in SICs. Remarkably, the performance of the SIC full-cells is very comparable to the most commonly used formulation of sodium hexafluorophosphate in ethylene carbonate:propylene carbonate (1 mol L⁻¹ NaPF₆ in EC:PC). Furthermore, presodiation strategies were compared for the novel electrolyte system. The in situ oxidation of a sacrificial salt (sodium squarate, Na₂C₄O₄) incorporated into the positive electrode yielded comparable results to the ex situ electrochemical approach. X-ray photoelectron spectroscopy studies revealed that depending on the presodiation strategy, the solid-electrolyte-interphase composition varies significantly.

Imperfect overpotential and inadequate reaction dynamics of the oxygen evolution reaction (OER) are the main factors limiting the efficient synthesis of H₂ by water electrolysis. One intriguing method for replacing slow OER and coupling with cathodic hydrogen is the thermodynamically advantageous urea oxidation reaction (UOR) production because of its equilibrium potential, which is less (0.37 V) than OER (1.23 V). And, for effective hydrogen generation, earth-abundant, inexpensive bifunctional electrocatalysts must be used in place of noble-metal-based electrocatalysts. Herein, in situ growth of Ru-doped bimetallic sulphide (RCNS@nickel foam (NF)) on NF was synthesised using the hydrothermal method followed by a calcination procedure. According to experimental findings, the as-prepared RCNS@NF electrode exhibits exceptional catalytic performance due to its pyramid nanostructure, crystalline nature, and synergistic impact. It only demands 1.43 V and 16 mV versus reversible hydrogen electrode for UOR and hydrogen evolution reaction (HER) to attain ±20 and ±10 mA cm⁻². However, to drive 10 mA cm⁻², a two-electrode cell system needs only 1.35 V potential, and it exhibits robust durability for 20 h of continuous testing @10 mA cm⁻² without any discernible activity diminution. Therefore, the present work suggests an approach for creating an extremely effective dual-functional catalyst for UOR and HER.

Precursor additives are crucial for enhancing the efficiency and stability of perovskite solar cells. However, their traditional selection of additives primarily relies on empirical trial-and-error approaches, which are time-consuming and inefficient. Herein, we utilize Perovskite-R1, a large language model, to rapidly identify an efficient additive: ethyl 2-aminopropanoate hydrochloride (EAH). This additive simultaneously passivates defects and regulates crystallization through the coordination of its –CO and –NH₃⁺ groups with the uncoordinated Pb²⁺ and I⁻ ions in the perovskite. These interactions significantly improve charge-carrier transport and suppress nonradiative recombination, leading to a champion power conversion efficiency (PCE) of 22.58%. Furthermore, the EAH-modified device exhibits excellent long-term stability, maintaining 95.1% and 94.1% of its initial PCE after 1368 h of storage in N₂ and 1272 h of thermal aging at 65°C, respectively. This study highlights the potential of integrating artificial intelligence with materials design to accelerate the discovery of high-performance, stable, and sustainable perovskite optoelectronic materials.

Photocatalytic hydrogen evolution represents a pivotal technology for sustainable energy conversion, yet its efficiency is fundamentally constrained by the limited light absorption and rapid charge recombination of most semiconductor photocatalysts. Herein, we demonstrate that the controlled aggregation of polymeric carbon nitride (PCN) nanosheet is a powerful strategy to overcome these limitations. We systematically reveal that aggregation fosters spatial electronic interactions, effectively extending the optical absorption of PCN into the red-light region. Furthermore, the accompanying weak noncovalent interactions induce spontaneous symmetry breaking within the aggregates, generating a built-in electric field that suppresses charge recombination. This synergy endows the aggregated PCN nanosheets with enhanced photocatalytic activity, achieving an apparent quantum yield (AQY) of 26.69% at 420 nm. Most notably, we report for the first time that the PCN nanosheet aggregates enable efficient hydrogen evolution under low-energy red light (610 nm), with an AQY of 3.04%, a capability entirely absent in their monomeric form. This study not only provides fundamental insights into aggregation-induced effects but also establishes aggregation engineering as a novel and effective paradigm for designing high-performance, broadband-responsive PCN photosystems.

Pharmaceutical residues, especially non-steroidal anti-inflammatory drugs (NSAIDs), are emerging contaminants that hinder sustainable water management and limit wastewater upcycling. In this work, we address the challenge of wastewater upcycling via the scale-up of a hybrid advanced oxidation process (AOP) that couples hydrodynamic cavitation (HC) and non-thermal electrical discharge (ED) plasma, and that will enable the in situ generation of ROS. In order to demonstrate process scalability, the hybrid HC/ED plasma system was initially validated at pilot scale (600 L h⁻¹) and subsequently up-scaled to a semi-industrial reactor (3200 L h⁻¹), specifically designed starting from the pilot unit. The effective exploitation of HC/ED plasma synergy led to the process achieving the quantitative degradation of model pollutants, specifically ibuprofen and diclofenac (10 mg/L), in competitive times (13 passes) and without detectable byproducts, thereby validating the process’ robustness and successful scale-up. Although current wastewater treatment plants (WWTPs) recover nutrients from sludge, biologically treated effluents still contain pharmaceutical residues. This work therefore, potentially solves this issue by providing a sustainable strategy for complete wastewater upcycling in WWTPs, delivering safe regenerated water for agricultural and irrigation reuse, while closing the water cycle.