Sustainable Energy & Fuels最新文献

To meet the growing global energy demand and keep our planet healthy, more than 10 terawatts of carbon-neutral energy will be required by 2050. H₂, which has an energy density of 33.33 kW h kg⁻¹, has been identified as a renewable and clean energy carrier to meet this energy demand and as a substitute for fossil fuels. H₂ storage is crucial for harnessing H₂ energy to its fullest potential and realizing the H₂ economy. Although compression and liquefaction are established H₂ storage techniques, safety concerns, energy consumption (up to 18 and 40% of H₂'s LHV for compression and liquefaction, respectively), and boil-off losses of up to 3% per day in liquefaction remain the main limitations. Researchers currently are exploring safe, compact, and efficient solid-state H₂ storage methods. Complex hydrides such as LiBH₄, NaBH₄, LiAlH₄, and NaAlH₄, which are formed by the coordination of complex anions such as [BH₄]⁻ and [AlH₄]⁻ stabilized by metal cations such as Na⁺, Li⁺, Mg²⁺, and Ca²⁺, are a class of solid-state H₂ storage materials with promising storage capacities. In principle, most of them are capable of meeting the ultimate volumetric (0.05 kg H₂ per L) and gravimetric (6.5 wt%) storage capacity goals set by the U.S. DoE. However, they suffer from unfavorable thermodynamics-T_des (150–600 °C), high desorption kinetic barrier-E_ades (50–275 kJ mol⁻¹), and limited reversibility. One intriguing approach to address these limitations is nanoconfinement in suitable host materials, benefiting from the synergetic effects of nanosizing, immobilization, destabilization, and, sometimes, catalysis for scaffolds that mutually induce catalytic effects. In this review, major H₂ storage techniques are briefly discussed. Developments in the nanoconfinement of complex hydrides, host materials, synthetic methods, characterizations, and advances in improving kinetics, thermodynamics, and reversibility via nanoconfinement are discussed. This paves the way for the use of hydrides in practical H₂ economy technologies, and contributes to the advancement of clean energy solutions.

In this work, we present the development of a fully rechargeable bio-battery, powered by Saccharomyces cerevisiae and utilizing recyclable PET carbon-based electrodes. Through the integration of yeast with the iota-carrageenan hydrogel and potassium ferricyanide as a redox mediator, the bio-battery consistently delivers 450 mV with excellent cyclability. This eco-friendly approach demonstrates great potential for advancing sustainable energy solutions, particularly in powering low-energy applications such as biomedical devices. Ongoing advancements in membrane design are expected to significantly boost the long-term performance and operational stability of this system, further solidifying its applicability in real-world scenarios.

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play a vital role in the functioning of Zn–air batteries and similar energy storage systems. These reactions are kinetically sluggish, which limits the performance of rechargeable Zn–air batteries. An effective bifunctional electrocatalyst that can replace the current noble metal based expensive systems is the need of the hour. In this study, Mn-doped cobalt oxide was synthesized using a cobalt zeolitic imidazolate framework (Co-ZIF) as a template. Mn-doped Co-ZIFs with different Co : Mn ratios (0.5, 1, and 2) were prepared using a single-pot technique and converted into corresponding Mn-doped cobalt oxides via calcination. Structural features were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Mn-Co₃O₄ displayed a high Brunauer–Emmett–Teller (BET) surface area of 69 m² g⁻¹ and a high pore volume. Among all the studied compositions, Mn-Co₃O₄-1 (Co : Mn = 1) exhibited the best performance, illustrating the crucial role of an optimum level of Mn doping. Mn-Co₃O₄-1 displayed a low ORR onset potential of 0.94 V and high mass transfer limited current density of 5.65 mA cm⁻². The catalyst exhibited a low overpotential of 330 mV at a current density of 10 mA cm⁻² for the OER. It also exhibited excellent ORR and OER stability and good bifunctionality, with a potential difference of 0.71 V. This study illustrates the excellent performance of Mn-doped cobalt oxides produced using ZIF templates in oxygen electrocatalysis.

Lithium-ion battery technology, currently the most popular form of mobile energy storage, primarily uses graphite as the anode. However, the graphite anode, owing to its low working voltage at high current density, is susceptible to lithium plating and related safety risks. In this direction, perovskite oxides like CaSnO₃, more recently PbTiO₃, have been explored as alternate anode materials due to their higher operational voltage. Extending this family of perovskites, we introduce a widely used lead-free piezoelectric ceramic Na_0.5Bi_0.5TiO₃ (NBT) as a potential anode for lithium-ion batteries. NBT has an average voltage of 0.7 V and a high capacity of 220 mA h g⁻¹. Ex situ diffraction and spectroscopy tools were used to understand the charge storage mechanism. The oxide undergoes an irreversible conversion reaction in the first discharge, followed by reversible (de)alloying of Bi with Li in the subsequent cycles. This material is airstable, with a capacity retention of 82% up to 50 cycles at a high current of 100 mA g⁻¹ without any optimization. Furthermore, limiting the voltage window increases the cycle life to 200 cycles. Perovskite-type Na_0.5Bi_0.5TiO₃ is proposed as a new Bi-based conversion alloying anode for lithium-ion batteries.

The synthetic insertion of carbon dioxide into organic scaffolds typically requires the reaction of CO₂ with a carbanion (carboxylation step), with the latter being generated through chemical, electrochemical, or photochemical routes. Still, little is known about the energetic and structural requirements of this step. In this work, we unveil the reactivity of CO₂ with a selected set of 28 carbanions through DFT calculations and provide linear free-energy relationships that correlate the ΔG⁰ and the ΔG^‡ of the carboxylation step. These reveal a Leffler–Hammond parameter α = 0.26 ± 0.02 and an intrinsic barrier ΔG^‡₀ = 12.7 ± 0.3 kcal mol⁻¹ (ωb97XD/aug-cc-pvtz//ωb97XD/def2tzvp level of theory), indicative of smooth reactivity of carbanions with CO₂. This reactivity is further associated with the basicity of the carbanions (expressed as the pK_aH of the conjugate acid), in a linear Brønsted plot between calculated ΔG^‡ and experimental pK_aH (slope β = 0.40 ± 0.04 kcal mol⁻¹). According to the Mayr–Patz equation, calculations allow the extrapolation of electrophilicity values for CO₂ in the range from −15.3 to −18.7, in good agreement with a single reported experimental value of −16.3. Concerning the structural changes occurring in the transition state, the major energy penalty comes from the distortion of CO₂. These findings can be useful in designing novel reactivity targeting carbon dioxide fixation.

Exploring lignin depolymerization and modification can yield high-value chemicals and liquid fuels, thereby enhancing resource utilization efficiency and alleviating pressure caused by energy shortages. In this paper, lignin-based carbon materials (Co-ZIF@KL-1 and Co-ZIF@KL-2) loaded with a metal–organic framework (ZIF-67) on kraft lignin biochar (KL) were prepared using two different methods (In situ method and traditional immersion method). In addition, catalysts with Co metal loaded on KL biochar (Co@KL) and ZIF-67 catalyst were also prepared for comparison with the above two different Co-ZIF@KL-1 and Co-ZIF@KL-2 catalysts. These catalysts were all applied to the hydrodeoxygenation (HDO) of guaiacol. Among them, the Co-ZIF@KL-1 catalyst exhibited the highest catalytic activity with 94.53% conversion of guaiacol and 83.86% selectivity of cyclohexanol under the optimal reaction conditions of 240 °C, 2.0 MPa N₂, and 4 h. The superior catalytic performance can be attributed to its high surface area, strong stability, and appropriate acidic sites. Based on the distribution of catalytic products, pathways for the guaiacol HDO reaction are hypothesized. In general, ZIF materials and lignin composites offer substantial value for advancing biomass catalytic conversion in the future.

The catalytic performance of a nickel catalyst in the methanation reaction is strongly influenced by the nickel loading in the catalyst. However, a high nickel content in the catalyst can result in significant nickel agglomeration and sintering, leading to reduction in the number of the active sites available for the methanation reaction, ultimately resulting in poor catalytic performance. Herein, an efficient nickel catalyst with up to 20 wt% of highly dispersed nickel species was successfully synthesized by a straightforward wet chemical method. The optimal composition of the catalyst was selected by using an orthogonal experimental scheme and range analysis method. During the preparation process, acid-treated clay was used as the support, and amino acids were employed as ligands for nickel ions. The amino groups in amino acids can coordinate with the nickel ions, forming nickel-amino acid framework nanocrystals on the clay layers and thus obtaining a catalyst with a high content of highly dispersed nickel species on the clay layers. The catalyst demonstrated an impressive single pass CO conversion of nearly 100% and a methane selectivity exceeding 82% in the CO methanation reaction, and it exhibited a single pass CO₂ conversion surpassing 91% and a remarkable 100% methane selectivity in the CO₂ methanation process. Furthermore, the catalyst showcased excellent stability throughout both reactions, further highlighting its potential for practical applications. This study offers a promising approach for the synthesis of efficient nickel catalysts with high nickel contents of highly dispersed active sites.

As a clean energy harvesting technology, triboelectric nanogenerators (TENGs) are becoming increasingly crucial in natural energy harvesting. However, due to the characteristics of natural wind, including randomness and broad wind speed ranges, efficient harvesting of wind energy has become a significant obstacle to developing wind energy TENGs. For this purpose, a fast-response triboelectric nanogenerator (FR-TENG). for gust energy capture is proposed in this paper. It contains a multilayer structure with four rotors; the slider mass is different on each layer of the mechanical switch to achieve graded harvesting of wind energy. Experiments proved that by grading settings, the efficiency of harvesting wind energy of the FR-TENG dramatically improves, and the output electrical signal of the FR-TENG can also be significantly enhanced. In the process of charging a 13 μF capacitor at 11.9 m s⁻¹ wind speed, the charging speed of the FR-TENG is approximately 2.25 times that of the Stepless Wind Energy Triboelectric Nanogenerator (S-TENG). When the wind speed is about 9 m s⁻¹, the FR-TENG can light up 640 light-emitting diodes (LEDs) and typically supply power for a thermometer. In addition, after durability testing, the performance of the FRTENG can be maintained at approximately 97%. Therefore, this paper provides a valuable method for collecting efficient and stable wind energy.

Zinc ion hybrid capacitors (ZIHCs) are expected to be one of the most promising energy storage devices due to their affordability, high level of safety, durability and exceptional electrochemical performance. However, the widespread applications of ZIHCs are often hindered by the low specific capacity and energy density of cathode materials. Faced with these challenges, we employed a template strategy to construct oxygen-doped porous carbon nanoflake (PCN) cathode materials with abundant defective sites as a potential candidate for the cathode material of ZIHCs. PCNs possess a substantial specific surface area of 1134 m² g⁻¹ with a hierarchical porous structure, and a high oxygen doping level of 19.0 at%, offering abundant active sites to enhance the storage capacity of PCN-based ZIHCs. Consequently, ZIHCs assembled from PCNs exhibit an extraordinary specific capacity of 179.3 mA h g⁻¹ at 0.1 A g⁻¹, excellent cycling stability with no obvious capacity decay over 5000 cycles even at 10 A g⁻¹, and an outstanding energy density of 116.7 W h kg⁻¹. Additionally, ex situ experiments were conducted to study the dynamic behaviors (adsorption/desorption) between zinc ions and anions of PCN-based electrodes during the charge and discharge process. This work highlights the importance of introducing rich oxygen-containing functional groups to carbon electrodes for constructing ZIHCs with outstanding performance.

During the COVID-19 pandemic, disposable masks were widely used, which raised substantial environmental concerns due to their improper disposal and plastic pollution. The masks, primarily made from polypropylene, represent not only an environmental degradation problem, but also an opportunity for energy recovery. In an innovative approach, these used masks were converted into ‘mask oil,’ which can be used as an alternative fuel for diesel engines, providing a sustainable solution to waste management and energy conservation. The mask oil, derived from the degradation of used masks, exhibits properties that make it a viable alternative to conventional diesel fuel. Its low density and kinematic viscosity enable it to atomize and vaporize more rapidly, which results in a greater efficiency of combustion. A lower flash point reduces ignition delay and accelerates combustion initiation, while a higher fire point ensures sustained combustion. According to GC-MS analysis, the mask oil contains a mixture of hydrocarbons and oxygenated compounds that enhance its lubricity and burning properties. FTIR analysis revealed functional groups such as alkenes and alcohols that enhance the reactivity and combustion efficiency of the oil. A test on a Kirloskar TV1 diesel engine demonstrated superior heat release rates and cylinder pressures in comparison to diesel, as well as lower unburned hydrocarbon emissions.