Sustainable Energy & Fuels最新文献

Potassium niobate, KNb₃O₈ (KNO) material is investigated as a potential anode material for sodium ion batteries owing to its layered structure and excellent electrochemical stability. However, the poor electrical conductivity of the material is addressed by surface modification with fluorine-doped carbon utilizing polyvinylidene fluoride as both a carbon and fluorine source. High resolution transmission electron microscopy results reveal that the active material is successfully embedded in the carbon matrix and X-ray photoelectron spectroscopy analysis confirms the tight attachment of carbon and fluorine bonding with the bulk material. As a result, the KNO@F–C material delivers a high reversible capacity of 173 mA h g⁻¹ at a current density of 10 mA g⁻¹, a superior rate performance of 137 mA h g⁻¹ at 200 mA g⁻¹ and a remarkable capacitance recovery rate (>100%). In addition, the coated material exhibits 90% capacity retention, demonstrating its long term cycling stability even after 200 cycles. The enhanced electrochemical performance of the coated sample over the pristine material is attributed to its large specific surface area, and a high Na⁺-ion diffusion coefficient, which facilitates a rapid transfer of electrons and improves grain-to-grain conductivity.

Environmentally friendly, metal-free photocatalysts offer a promising alternative to traditional metal-based semiconductors. In this study, we synthesised graphitic carbon nitride (CN) photocatalysts decorated with carbon dots (CDs) using two distinct methods: a hydrothermal approach and a solvent-free mechanochemical extrusion method. The resulting nanocomposites were thoroughly characterised for their physical, chemical, and optical properties and evaluated for photocatalytic activity in the selective oxidation of benzyl alcohol. Results revealed that the synthetic approach significantly impacted the composites' morphological and optical characteristics, affecting their photocatalytic performance. A light–matter interaction modelling study was further conducted to explore the relationship between optical properties and catalytic behaviour, offering valuable insights into the structure–function relationship of these novel photocatalysts. As a result, we present an alternative scheme to traditional synthesis and catalysis methods based on the use of high temperature and pressure conditions, which provides an energetically positive and environmentally friendly approach.

The morphology of the active layer mostly affects the photovoltaic efficiency of organic solar cells (OSCs). Optimizing the configuration of the bulk heterojunction (BHJ) is a very effective approach to enhancing the donor–acceptor network in the active layer. This work aims to examine the influence of a gallium (Ga) doped ZnO electron transport layer (ETL) and a solid additive 1,4-diiodobenzene (DIB) on the nanomorphology and performance of an inverted OSC. Nevertheless, the challenge of selecting appropriate solid additives for device optimization is arduous due to the extensive range of organic photovoltaic materials obtainable. This study presents the utilization of DIB as a solid additive to enhance the efficiency of OSCs. The utilization of modified ETL and DIB as solvent additives has been found to enhance the development of a desirable nanomorphology characterized by a bi-continuous interpenetrating network of donor and acceptor. Devices treated with DIB have significantly enhanced performance compared to control devices. In the case of non-fullerene OSCs, the power conversion efficiency (PCE) achieved a value of 16.67%. Additionally, employing DIB in the production of OSCs results in enhanced charge transport and extraction, improved crystallinity, reduced charge recombination, and superior phase separation. We provide evidence that the utilization of additive engineering is a very efficient approach for improving the efficiency of organic solar cells.

The rational design of high-energy-density (HED) sustainable aviation fuels (SAFs) often relies on understanding the electronic structures of fuel hydrocarbons. This study uses density functional theory (DFT) to investigate the exo-chair and exo-boat isomers of Jet Propellant 10 (JP-10) fuel. The exo-chair isomer is found to be more stable by 1.83 kcal mol⁻¹, with an energy barrier of 3.65 kcal mol⁻¹ separating the two using the B3LYP/cc-pVTZ method. Despite small geometric differences, significant changes in the shape, dipole moments (0.0156 Debye for the exo-chair and 0.0426 Debye for the exo-boat) and NMR chemical shifts at the flag carbon (C5), the boat tip carbon (C10) and the hydrogens bonding with them. The B3PW91/cc-pVTZ method produces more accurate carbon NMR chemical shifts (RMSD (δ_C) = 1.48 ppm) than the B3LYP/cc-pVTZ method (RMSD (δ_C) = 3.21 ppm), whereas the reverse holds for the proton-NMR chemical shifts, RMSD (δ_H) = 0.33 ppm and 0.31 ppm, in agreement with early studies. The NMR trajectories during the chair and boat transition reveal the most significant changes at the transition state (TS). In addition, the carbon atoms engaging larger strain (e.g. junction carbons and the flag carbon) exhibit apparent deshielding. Excess orbital energy spectrum (EOES) analysis further identifies key inner valence orbital changes during the isomerization, indicating the role of bonding interactions in stabilizing the exo-chair isomer. These findings offer valuable insights into the electronic structural factors that influence the stability of multicyclic hydrocarbons, aiding the future design of more efficient SAFs.

Anion exchange membranes (AEMs) are a vital component of aqueous organic redox flow batteries (AORFBs). Conventional AEMs often suffer from high resistance and typically lack mechanical strength and durability, particularly when used over large areas. In this work, we report a high-performance combination membrane (CM) formed by the straightforward adhesion of a hydrophilic porous polyethylene (HPE) layer to an AEM. The exceptional hydrophilic stability of HPE in the electrolyte endows this CM with remarkable stability in single-cell operations. Furthermore, the CM effectively prevents electrolyte crossover while facilitating efficient anion transport, demonstrating long-term stability in a 52-stack battery, with each CM scaled up to an active area of 830 cm². This work presents a facile and scalable method for fabricating highly durable AEMs, offering significant advancements in the field of AORFBs.

The development of innovative electrodes with outstanding high-rate cycling performance for the next generation of sulfur-based batteries has emerged as a key area of research. This study presents a straightforward approach for designing silicon/graphene nanoplates as an anode material using a one-step hydrothermal process. Additionally, to reduce the shuttle effect, the GNP/MnO₂/S cathode is investigated. In this study, MnO₂ particles are grown in situ on the surface of the GNP. The pre-lithiation Si/GNP anode and the MnO₂/GNP/S and GNP/S cathodes are evaluated at a current density of 1000 mA g⁻¹. The findings reveal an impressive capacity retention of 1048 mA h g⁻¹ after 200 cycles, indicating remarkable cycling performance for the cell with the pre-lithiation Si/GNP anode and the MnO₂/GNP/S cathode. The capacity retention observed in thicker electrodes highlights the synergistic effect of the effective chemical absorption of lithium polysulfides by MnO₂/GNP/S when used as sulfur hosts. Additionally, DFT calculations suggest that MnO₂ has a significant tendency to adhere to the surface of polysulfides, aligning well with our findings regarding cycle performance, rate performance, and discharge capacity. The novel electrode configuration introduced in this study provides a novel pathway for the large-scale production of high-performance pre-lithiation Si–S batteries.

This study investigates the valorization of restaurant-derived food waste into biocrude using hydrothermal liquefaction (HTL). The selected feedstocks, including carrot, parsnip, and other vegetables, were evaluated for their physicochemical properties, showing low ash (9.1–22.0 wt%) and fixed carbon content (5.3–18.4 wt%) with high moisture levels (79–95% wet basis), suitable for HTL without additional drying. Carrot emerged as the optimal feedstock due to its elevated carbon (44.9 wt%), hydrogen (7.8 wt%), cellulose (15.3 wt%), and hemicellulose (4.1 wt%) content. Reaction parameters optimized via response surface methodology (280 °C, 1500 psi, 42 minutes) yielded 18.8 wt% biocrude with a carbon recovery of 55.9–72.8%. Quality analyses such as gas chromatography-mass spectrometry and Fourier-transform infrared spectroscopy highlighted the complex composition of biocrude, including esters, hydrocarbons, and oxygenated compounds, confirming its potential for biofuel applications. Solvent optimization experiments demonstrated that methanol was the most effective, yielding 19.6 wt% biocrude. Additionally, methanol actively participated in the extraction process by promoting esterification, generating methyl esters, as evidenced in gas chromatography-mass spectrometry analysis. These reactions enhance product yield and quality by forming bioactive compounds like methyl esters, which improve the bio-oil stability and calorific value. Despite high oxygen content (20.7 wt%), the biocrude properties can be upgraded via deoxygenation techniques, paving the way for its use as a sustainable transportation fuel. This research underscores hydrothermal liquefaction as an effective approach to manage food waste while addressing global energy challenges through renewable bioenergy production. By integrating statistical optimization and comprehensive characterization, this study contributes to advancing biofuel technology and sustainable energy solutions.

Developing efficient and stable metal-free photocatalysts for hydrogen evolution reaction (HER) in seawater is crucial for advancing sustainable hydrogen production. While the potential of graphene quantum dots (GQDs) as HER photocatalysts has been established, they face limitations such as inadequate spectral absorption in the visible light spectrum and the presence of electron trap sites. This study introduces a metal-free photocatalyst composed of hexylamine-functionalized graphene quantum dots (GQD-HA) in combination with the ionic organic dye TPATCS, specifically engineered to tackle the challenges associated with HER in seawater. The introduction of amphiphilic assembly between GQD-HA and TPATCS results in strong intermolecular interactions, forming a robust and stable nanostructure. This structure not only demonstrates superior hydrogen evolution rates in simulated seawater compared to standalone TPATCS but also maintains a stable zeta potential and consistent morphology under irradiation, highlighting its significant photostability. The amphiphilic assembly enhances the photocatalyst's performance by effectively passivating electron trapping sites through the formation of amide bonds between GQD and HA, which improves charge separation and transfer while restoring n-type conductivity. These features are critical for optimized HER activity. This approach showcases a promising strategy for developing efficient, stable, metal-free photocatalysts for seawater HER, offering new perspectives on the design of self-assembled dye-sensitized photocatalysts for sustainable energy solutions.

Hydrothermal liquefaction (HTL) represents a transformative technology in the quest for net-zero emissions and the establishment of a circular bio-economy. This study investigates an innovative approach to waste valorization by converting digestate fibers from biogas plants into renewable fuels using HTL and catalytic upgrading. The HTL process yielded biocrude with 37 wt% and achieved 70 wt% energy recovery from the dry ash-free biomass, demonstrating HTL's efficiency in capturing energy from biowaste. Catalytic upgrading of the biocrude, including hydrotreatment (HDT) and other refining steps, reduced the oxygen content by 98% to 0.16 wt%, and boosted energy density to 45.8 MJ kg⁻¹, aligning with ASTM D975 standards for diesel and ISO 8217 for marine fuels. The feasibility of co-processing biocrude with conventional heavy oil was also explored. Blending trials with 10 wt% partially upgraded biocrude showed stable performance over 200 hours in an HDT reactor, indicating compatibility and a viable pathway for integrating renewable biocrude with traditional heavy distillates, enhancing fuel production sustainability. This approach provides a promising route to incorporate renewable sources into conventional fuel production, supporting sustainable fuel technologies.

Under ambient conditions, one efficient way to transform the greenhouse gas carbon dioxide (CO₂) into carbon-containing compounds is the electrocatalytic CO₂ reduction reaction (CO₂RR). However, electrocatalysis depends on the aid of the liquid phase interface, and the competing hydrogen evolution reaction (HER) inevitably occurs, which greatly reduces the efficiency of the CO₂RR. As a result, creating effective hydrogen suppression catalysts with excellent stability and selectivity is a difficult but vital undertaking. Scholars have focused much work on developing efficient synergistic interactions between silver and metal oxides; however, the requirement of high faradaic efficiency (FE) cannot be met by depending only on the synergistic interaction between silver metal and metal oxides. Therefore, this paper proposed the idea of modifying silver with exogenous ligands and then combining it with metal oxides to form new composite materials. To increase carbon monoxide (CO) selectivity and cathodic energy efficiency, a sulfhydryl ligand modified silver-titanium dioxide catalyst (Ag/AgS–TiO₂) was prepared and reported in this work. It demonstrated excellent CO selectivity (>90%) as a CO₂RR catalyst throughout a broad electrode potential range of −1.1 to −1.4 V (vs. the reversible hydrogen electrode (RHE)); its cathodic energy efficiency reached 51.7%, surpassing that of the majority of silver-based electrocatalysts. The competitive hydrogen evolution process was inhibited, *CO was formed more easily, and the essential intermediates for CO₂ reduction were optimized with the presence of sulfhydryl ligands. This work presented a novel approach to the construction of CO₂RR catalysts that combine TiO₂ and silver.