EcoEnergy最新文献

Hydrogen serves as an ideal clean energy with zero carbon emissions, whereas its large-scale application relies on its liquidation, by which the catalytic conversion of ortho–para H₂ at cryogenic temperature is inevitable with iron oxides as a promising catalyst. In this research, iron oxides with varied surface area and diverse phases were synthesized from the precursor of hydrous ferric oxide, including α-Fe₂O₃, γ-Fe₂O₃, and Fe₃O₄. The bulk and surface properties of these catalysts were characterized by XRD, BET, TG, IR, magnetic analysis, hydrogen adsorption, and ⁵⁷Fe-Mössbauer spectrum. It was suggested that ortho–para H₂ conversion is linearly correlated with the specific surface area of α-Fe₂O₃ which governs the residual magnetic properties as well as the adsorption capacity of molecular H₂ on the catalysts, and a nondissociation mechanism of ortho–para H₂ conversion was revealed at cryogenic temperature. The hydrate that contributed to the surface area of iron oxides shows a negative effect on the ortho–para H₂ conversion. Moreover, by estimating the reaction rate based on the per surface area of iron oxides, the Fe(III) exposed on surfaces exhibited a superior activity irrespective of the bulk magnetism of iron oxides, and the intrinsic activity of iron oxides for ortho–para H₂ conversion was found to follow a trend similar to that of α-Fe₂O₃ ≈ γ-Fe₂O₃ > Fe₃O₄. The findings of this study provide valuable insights for the subsequent research on the mechanism of ortho–para H₂ conversion and the design of high-performance hydrogen liquefaction catalysts.

Hematite is a promising candidate material for photoanodes, but the efficiency of the state-of-the-art hematite photoanodes is limited by the low absorption coefficient, short hole diffusion length, and slow water oxidation kinetics. In this work, a high-efficiency hematite photoanode was designed and fabricated by introducing titanium-doped hematite (Ti:Fe₂O₃) homojunction with different doping contents and a hierarchical nanorod/nanobowl array structure. The homojuction consisted of low Ti doping nanorods grown on high Ti doping nanobowl arrays, leading to the formation of a broad built-in electric field, significantly enhancing the charge separation and transfer within the bulk. Furthermore, the nanorods radially grown inside the bowls and on the bowl edges enabled enhanced light absorption through multiple light scattering while offering a larger electrode–electrolyte contact area and providing more reaction sites. Compared to the Ti:Fe₂O₃ nanorod arrays, the Ti:Fe₂O₃ nanorod/nanobowl array photoanode exhibited an increase in photocurrent density from 1.6 mA cm⁻² to 3.0 mA cm⁻² at 1.23 V versus RHE, maintaining long-term stability over 100 h at 1.23 V versus RHE. This study not only achieved a high-performance hematite photoanode but also provided a new perspective on the design of differently doping homojunction photoanodes with desired nanostructures.

Heterostructure catalyst is highly efficient for photoelectrolytic (PEC) wastewater remediation, while rationally constructing the photoelectrocatalyst with a high-quality interface is still challenging. Herein, a simple hydrothermal process prepares a heterostructure NiMoO₄@α-MnO₂ with a uniform interface between NiMoO₄ nanosheets and α-MnO₂ nanowires. NiMoO₄@α-MnO₂ exhibited significant advantages as follows: (1) α-MnO₂ nanowires act as charge transport channels like the arteries that transport nutrients, promoting the migration and separation of induced charges; (2) the pollutants can be electrostatically concentrated to the surface of the NiMoO₄@α-MnO₂. Specifically, the gossamer-like NiMoO₄ nanosheets adhering on the surface of the α-MnO₂ have a large surface area, beneficial for electrolyte penetration and utilization of active sites. (3) Unfolded gossamer-like NiMoO₄, like a vast extended solar panel of an artificial satellite, can harvest more solar energy, generating lots of electron (e⁻)/hole (h⁺) pairs and active species, offering multiple transfer pathways and speeding up the rate of the degradation reaction. The optimized heterostructured NiMoO₄@α-MnO₂-3.5 catalysts showed superior PEC activity and remarkable stability for degrading reactive brilliant blue KN-R. Z-scheme heterojunction between α-MnO₂ and NiMoO₄ is proposed based on their energy band structure and free radical quenching experiment.

Solid–solid phase change materials usually suffer from the challenges of low thermal storage capacity and poor mechanical strength in thermal management applications. Additionally, solid–solid phase change materials are often prepared by a chemical cross-linking strategy, leading to poor recyclability. This study highlights a straightforward and effective strategy to prepare multiple H-bonding cross-linking supramolecular solid–solid phase change materials integrating easy recyclability, high mechanical strength, and high latent heat characteristics for thermal management of lithium batteries.

Novel renewable alternatives to meet the needs of our current energy landscape are highly sought after. Photovoltaic solar cells (PV) are considered leading candidates for carbon neutrality due to their numerous benefits and good solar-to-energy conversion efficiency. However, the need is no longer solely focused on electric current generation but also on strategies to store that energy. This led, amongst other technologies, to the development of dye-sensitized photoelectrosynthesis cells (DSPECs), the successor of dye-sensitized solar cells (DSSCs). However, these cost-effective solar cells mostly use photosensitizers based on scarce metals such as ruthenium. Iron-based photosensitizers represent the holy grail due to their low toxicity, greater abundance, and versatile chemistry. However, they still suffer from drastic limitations: their photochemistry and extremely fast excited-state deactivation processes lead to inefficient charge injection and/or fast charge recombination. This review gathers examples of iron-based photosensitizers that have been successfully immobilized on metal oxide surfaces. A critical comparison of Fe-based photosensitizers is made based on their photophysical properties, electrochemistry, and photovoltaic performances.

Biomass-derived carbons are eco-friendly and sustainable materials, making them ideal for supercapacitors due to their high surface area, excellent conductivity, cost-effectiveness, and environmental benefits. This review provides valuable insights into biomass-derived carbon and modified carbon for supercapacitors, integrating both experimental results and theoretical calculations. This review begins by discussing the origins of biomass-derived carbon in supercapacitors, including plant-based, food waste-derived, animal-origin, and microorganism-generated sources. Then, this review presents strategies to improve the performance of biomass-derived carbon in supercapacitors, including heteroatom doping, surface functionalization, and hybrid composite construction. Furthermore, this review analyzes the functions of biomass-derived carbon in supercapacitors both in its pure form and as modified materials. The review also explores composites derived from biomass-based carbon, including carbon/MXenes, carbon/MOFs, carbon/graphene, carbon/conductive polymers, carbon/transition metal oxides, and carbon/hydroxides, providing a thorough investigation. Most importantly, this review offers an innovative summary and analysis of the role of biomass-derived carbon in supercapacitors through theoretical calculations, concentrating on four key aspects: energy band structure, density of states, electron cloud density, and adsorption energy. Finally, the review concludes the future research directions for biomass carbon-based supercapacitors, including the discovery of novel biomass materials, tailoring surface functional groups, fabricating high-performance composite materials, exploring ion transfer mechanisms, and enhancing practical applications. In summary, this review offers a thorough exploration of the sources, functions, and mechanisms of biomass-derived carbon in supercapacitors, providing valuable insights for future research.

Methane, recognized as a promising substitute for conventional fossil fuels due to its abundant availability, low cost, and high energy density, can be converted into value-added products, providing a sustainable energy–carbon utilization approach. However, its inert molecules require significant energy for C–H bond activation. Photocatalytic conversion offers an effective mild-condition solution, reducing thermocatalysis energy demands and enhancing activation efficiency for selective chemical production. This review systematically arranges photocatalytic C–H bond activation mechanisms, categorizes conversion products, and discusses challenges, prospects, and solutions for methane photocatalysis development.

Phase change materials (PCMs) that reversibly release or absorb thermal energy during phase transitions play a significant role in promoting renewable and sustainable energy development. However, the poor shape stability, low thermal conductivity, and inferior energy conversion efficiency of PCMs hinder their wider applicability and are difficult to meet the growing demand. As the precursor of carbon-based materials, including expanded graphite, graphene oxide, and graphene, natural graphite (NG) finds extensive applications and bring new potentials to the PCMs, enabling multiple cutting-edge thermal energy applications. Herein, we systematically discuss NG and its derivative-based composite PCMs for thermal energy storage, thermal energy conduction, and thermal energy conversion. This paper aims to offer insights into the roles of NG in PCMs and hope to provide a useful guide for the design of next-generation composite PCMs with high-energy-density, high thermal conductivity and high energy conversion efficiency.

Over the past few decades, significant advancements have been made in the development of low-temperature liquid electrolytes for lithium batteries (LBs). Ongoing exploration of liquid electrolytes is crucial for further enhancing the performance of these batteries. Solvation chemistry plays a dominant role in determining the properties of the electrolyte, significantly affecting LBs performance at low temperatures (LTs). This review introduces solvation structures and their impact, discussing how these structures promote fast desolvation processes and contribute to the improvement of battery performance. Additionally, various solvent strategies are highlighted to refine solvation chemistry at LTs, including the use of linear and cyclic ethers/esters, as well as the role of functional groups within these solvents. The review also summarizes the impact of lithium salts containing organic/inorganic anions on solvation chemistry. Characterization techniques for solvent chemistry are discussed, providing a comprehensive analysis that offers valuable insights for developing next-generation electrolytes to ensure reliable battery performance across a wide temperature range.