Sustainable Energy & Fuels最新文献

Layered double hydroxides (LDHs) are a structurally versatile class of materials, yet their potential for thermochemical energy storage (TCES) has remained unexplored. In this work, we present the first demonstration of LDHs as thermochemical storage materials operating through reversible hydration/dehydration reactions. The intrinsic structural flexibility of LDHs, composed of alternating layers of mixed divalent and trivalent cations charge-balanced by interlayer anions, may enable fine control over reaction thermodynamics and energy density. Among various cation/anion combinations, Mg/Al-LDH was synthesized and systematically evaluated as a reference material. Comprehensive structural (XRD, Raman, and Al-NMR) and thermal analyses (TGA, DSC, STA-water vapor) revealed good short-term cyclability for at least 40 cycles, with the material exhibiting a pronounced memory effect (reversibility) with an energy density of 532.4 J g⁻¹. These findings establish that layered double hydroxides could establish a promising family of materials for an extended range of temperature conditions in thermochemical heat storage.

The intensive use of fossil feedstocks has raised numerous concerns regarding their environmental impact. As of 2023, renewable energy including modern biofuels, traditional biomass, and other sources accounted for only 8% of global final energy consumption. Recently, our research group developed a novel methodology to convert second-generation biomass into a liquid product, which is a viscous, brown oil composed primarily of carbohydrate-derived O-isopropylidene ketals (CKs), with mono- and di-isopropylidene derivatives of glucose and xylose, called bio-petroleum (BP). Given the successful proof of concept for the direct conversion of BP into green hydrocarbons within refinery processes, the present study seeks to evaluate the capacity of various lignocellulosic biomasses to yield BP. The results presented in this study demonstrate that various lignocellulosic biomasses can be effectively converted into BP enriched in carbohydrate-derived isopropylidene ketals through hydrolysis–ketalization reactions under mild processing conditions. Up to 50% of the original biomass carbohydrate content was recovered in the form of monosaccharide diisopropylidene ketals in a sequence where hemicellulose is first removed, followed by amorphous cellulose, and finally crystalline cellulose. This progression enables temperature-controlled tailoring of BP composition, offering a means of modulating the performance of BPs in refinery downstream upgrading processes for fuel production.

The search for efficient, stable, and positive triboelectric materials is urgently needed to advance triboelectric nanogenerator (TENG) technology. Addressing this gap not only enhances device performance but also supports broader sustainability objectives, aligning with SDG-driven efforts toward clean energy, innovation, and responsible material use. While progress has been made with many negative triboelectric materials, the development of their positive counterparts remains limited. Therefore, bridging this gap is essential for achieving higher efficiency TENGs. In the present work, we propose transition metal chalcogenides (TMCs), specifically vanadium tetrasulfide (VS₄), as a new tribopositive material for the first time. The positive triboelectric nature of VS₄ is experimentally verified with simple electrostatic interaction tests, surface potential values and TENG-based tests. The VS₄-based TENG achieves an open-circuit voltage of ∼1.52 kV, a short-circuit current of ∼180 µA, a transferred charge of ∼200 nC, and a power density of 14.45 W m⁻² under biomechanical hand-tapping force. The obtained performance is the highest among the sulphur-TMC-based TENGs reported to date. This high-performance TENG device was capable of powering a series-connected array of 720 light-emitting diodes (LEDs) and 6 LED bulbs. The present findings establish VS₄ as a new positive material for the development of triboelectric energy harvesting and self-powered systems.

Electrolytes with a strong temperature dependence of the redox potential, denoted as the temperature coefficient, are required to increase the voltage of thermo-electrochemical devices. In our previous study, we revealed that the temperature coefficient of ferrocyanide/ferricyanide redox couple ([Fe(CN)₆]^4−/3−) dramatically increases in a mixture of water and tetrabutylammonium fluoride (TBAF) owing to the formation of semiclathrate hydrate (SCH). However, the temperature range in which a high temperature coefficient is obtained is limited to the vicinity of the SCH formation temperature. In this study, we demonstrate that this temperature range can be adjusted using organic salts that provide different SCH formation temperatures, such as tetrabutylammonium chloride and tetrabutylphosphonium chloride (TBPC). Replacing the organic salt affects both the temperature range and magnitude of the temperature coefficient. The calculation using the developed model to evaluate the contribution of SCH formation revealed the origin of the difference in temperature coefficient, such as the dependence of redox potential of [Fe(CN)₆]^4−/3− on organic salt concentration in the liquid phase, and the temperature dependence of organic salt concentration in the liquid phase. Furthermore, we assembled a thermo-electrochemical device for a charging-free thermally regenerative electrochemical cycle using electrolytes with different organic salts. The devices using different organic salts were operated in distinct temperature ranges: 292–297 K for the TBAF-based system and 276–280 K for the TBPC-based system. This study expands the applicability of high-voltage thermo-electrochemical devices driven by the SCH formation.

Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations were performed to investigate hydrogen storage in a carbon-doped boron nitride (BN) lattice derived from the 8-16-4 graphyne structure, decorated with lithium atoms. Carbon incorporation into the SBNyne lattice significantly increases the binding affinity of Li adatoms and prevents Li clustering. As a result, the newly developed material 2Li@C-SBNyne contains two strongly bound Li adatoms per unit cell that can adsorb hydrogen molecules efficiently. Each Li atom can coordinate up to four H₂ molecules, giving a maximum of eight H₂ molecules per C-SBNyne unit cell, with an average adsorption energy of approximately E_ad = −0.163 per H₂ and a hydrogen storage capacity of 7.12%. The adsorption energy lies within the optimal range for reversible storage, and the gravimetric capacity exceeds the U.S. Department of Energy (DOE) 2025 onboard hydrogen storage gravimetric target of 5.5 wt%. Thermodynamic analysis predicts a desorption temperature of approximately 209 K. AIMD runs of 8 ps at 209 K and 300 K show strong adhesion of the Li adatoms to the C-SBNyne lattice and preservation of the molecular integrity of the adsorbed H₂, indicating good thermal stability.

This review highlights the growing importance of electrocatalytic CO₂ reduction in sustainable energy production, focusing on overcoming key industrial challenges, such as catalyst instability, poor selectivity, and low energy efficiency. The electrochemical conversion of CO₂ into value-added fuels presents an environmentally friendly approach to mitigate pollution and climate change while offering a pathway toward carbon neutrality. This review summarizes recent advancements in the application of single-atom catalysts (SACs) for the CO₂ reduction reaction (CO₂RR) via electrolysis. Special attention is given to the various supports for single metal atoms, which are crucial for enhancing catalytic performance. Strategies such as optimizing the coordination environment, utilizing dual-atom sites, and incorporating heteroatom doping and defect engineering for improving the SAC performance are discussed. Finally, future strategies for advancing CO₂ electrolysis catalysts are proposed, aiming to address existing challenges and enhance their industrial applicability.

MXene-based photocatalysts have emerged as a versatile platform for solar-driven CO₂ reduction, offering new routes for sustainable fuel and chemical production. This review first outlines the fundamental structure, electronic/optical properties, and synthesis strategies of MXenes relevant to photocatalysis. It then critically discusses the roles of MXenes in CO₂ reduction, including co-catalyst behavior, charge-transfer mediation, and photothermal enhancement, within diverse heterostructure architectures such as 2D/2D junctions, S-scheme and Z-scheme systems, and ternary composites. Particular emphasis is placed on interfacial engineering and surface termination control to optimize charge separation and C₁/C₂ product selectivity, along with emerging AI/ML-guided approaches for rational MXene design. Sustainability aspects of MXene synthesis and deployment, including HF-free routes, scalability, energy input, and stability, are also evaluated. Finally, key research priorities are identified, encompassing operando stability, AI-guided termination and interface control, and device-level integration, to guide the development of practical MXene-based photocatalytic CO₂ reduction technologies.

Anaerobic digestion (AD) technology, as an important approach for the resource utilization of organic waste and the production of clean energy, still faces key challenges such as a prolonged acclimatization period, easy acidification and low methane production efficiency in practical applications. This paper systematically reviews the mechanisms of action and application prospects of carbon-based materials (such as biochar, activated carbon, carbon nanotubes, graphene, etc.) as multifunctional additives in improving AD performance. The core argument is that carbon-based materials significantly enhance system stability and methane yield through multiple synergistic pathways such as physical adsorption, chemical buffering, and bioelectron transfer (especially direct interspecies electron transfer, DIET). This paper constructs a cross-scale mechanistic analysis framework from material structural characteristics to microbial ecological functions, critically reviews the limitations of current research, and prospectively proposes future development directions such as rational material design, artificial intelligence (AI) and machine learning models for process optimization, and life cycle assessment, aiming to provide theoretical support and technical pathways for promoting the translation of carbon-based materials from laboratory research to industrial application.

Anion exchange membranes (AEMs) have emerged as pivotal components in fuel cell and water electrolyzer technologies, offering a cost-effective alternative to proton exchange membranes due to their operation under alkaline conditions. This review comprehensively analyzes the latest advancements in AEMs and their composite materials, focusing on their structural modifications, ionic conductivity, chemical stability, and performance enhancements. The development of novel polymer backbones, incorporation of nanofillers, and crosslinking strategies have significantly improved the mechanical robustness and ionic transport properties of AEMs, addressing long-standing challenges such as membrane degradation and conductivity limitations. Furthermore, the role of functionalized polymers, predominantly those with quaternary ammonium (QA) groups, in optimizing AEMs' physicochemical properties is discussed. Materials science innovations are explored, highlighting recent breakthroughs in enhancing fuel cell efficiency and electrolyzer durability. This review strives to bridge the gap between fundamental science and industrial application, paving the way for the next generation of high-performance electrochemical energy devices. The challenges and opportunities in the field are critically analyzed, offering strategic directions for future research and technological development in AEM-based energy systems.