材料导报:能源(英文)最新文献

Photocatalytic oxygen (O₂) reduction has been considered a promising method for hydrogen peroxide (H₂O₂) production. However, the poor visible light harvesting and low-efficient separation and generation of charge carriers of conventional photocatalysts strongly limited their photocatalytic H₂O₂ generation performance. Herein, we design a highly efficient photocatalyst in this work by marrying luminescent gold-silver nanoclusters (AuAg NCs) to polyethyleneimine (PEI) modified C₃N₄ (C₃N₄-PEI). The key design in this work is the utilization of highly luminescent AuAg NCs as photosensitizers to promote the generation and separation of charge carriers of C₃N₄-PEI, thereby ultimately producing abundant e⁻ for O₂ reduction under visible light illumination (λ ≥ 400 nm). As a result, the as-designed photocatalyst (C₃N₄-PEI-AuAg NCs) exhibits excellent photocatalytic activity with an H₂O₂ production capability of 82 μM in pure water, which is 3.5 times higher than pristine C₃N₄ (23 μM). This interesting design provides a paradigm in developing other high-efficient photocatalysts for visible-light-driven H₂O₂ production.

SiO_x is attractive as an anode material for lithium-ion batteries (LIBs) due to its high capacity, low cost, and relatively higher cyclic stability than Si anode. However, the intrinsic low electronic conductivity, low initial coulombic efficiency (ICE), and volume expansion during cycles hinder its applications. In this review, we summarize advances in high performance SiO_x anodes, mainly from two aspects: active material and binders. The future perspective is investigated at the end of this review. Our review provides strategical guidance for developing high performance SiO_x anodes.

The direct conversion of atmospheric CO₂ into fuel via photocatalysis exhibits significant practical application value in advancing the carbon cycle. In this study, we established an electro-assisted photocatalytic system with dual compartments and interfaces, and coated Ag nanoparticles on the titanium nanotube arrays (TNTAs) by polydopamine modification. In the absence of sacrificial agent and alkali absorption liquid conditions, the stable, efficient and highly selective conversion of CO₂ to CO at the gas-solid interface in ambient air was realized by photoelectric synergy. Specifically, with the assistance of potential, the CO formation rates reached 194.9 μmol h⁻¹ m⁻² and 103.9 μmol h⁻¹ m⁻² under ultraviolet and visible light irradiation, respectively; the corresponding CO₂ conversion rates in ambient air were 30% and 16%, respectively. The excellent catalytic effect is mainly attributed to the formation of P–N heterojunction during the catalytic process and the surface plasmon resonance effect. Additionally, the introduction of solid agar electrolytes effectively inhibits the hydrogen evolution reaction and improves the electron utilization rate. This system promotes the development of photocatalytic technology for practical applications and provides new insights and support for the carbon cycle.

Sodium-ion battery (SIB) is an ideal candidate for large-scale energy storage due to high abundant sodium sources, relatively high energy density, and potentially low costs. Hard carbons, as one of the most promising anodes, could deliver high plateau capacities at low potentials, which boosts the energy densities of SIBs. Their slope capacities have been demonstrated from the defect adsorption of sodium ions, while the plateau capacity depends highly on intercalation and pore filling. Nevertheless, the specific structures of sodium ions stored in hard carbons have not been clarified, namely active sites of adsorption, intercalation, and pore-filling mechanisms. Therefore, delicate synthesis methods are required to prepare hard carbons with controllable specific structures, along with elucidating the precise active sites for enhancing the Na-ion storage performance. To offer databases for future designs, we summarized the synthesis strategies of hard carbon anodes for constructing active sites of plateau capacities. Synthesis methods were highlighted with corresponding influences on the meticulous structures of hard carbons and Na-ion storage behaviors. Last but not least, perspectives were proposed for developing hard carbon anodes from the points of research and practical applications.

The deoxygenation of organic acids, important biomass feedstocks and derivatives, to synthesize hydrocarbon products under mild electrochemical conditions, holds significant importance for the production of carbon-neutral biofuels. There is still limited research on the influential factors of the electrochemical decarboxylation reaction of medium-chain fatty acids. In this study, n-octanoic acid (OA) was chosen as the research subject to investigate the electrochemical decarboxylation behavior of OA on a platinum electrode, focusing on the influence of different alkali metal cations (Li⁺, Na⁺, K⁺), common anions (SO₄²⁻, Cl⁻), and electrolyte pH. It was found that KOH as an electrolyte exhibited the best performance for OA. Possibly, the larger size of K⁺ increased the alkalinity of the electrode surface, facilitating OA deprotonation. LiOH electrolyte reduced the solubility of OA, thereby inhibiting the decarboxylation reaction. SO₄²⁻ exhibited a weak promoting effect on the decarboxylation reaction of OA, while Cl⁻ showed no adverse effect although Cl⁻ may adsorb on the electrode surface. Furthermore, unlike short-chain fatty acids, medium-chain OA can only achieve efficient decarboxylation under alkaline conditions due to its solubility properties. This study provides references and foundations for future efforts to enhance the efficiency of electrochemical decarboxylation synthesis of hydrocarbon biofuels from medium-chain fatty acids.

Photothermal conversion attracted lots of attention in the past years and sorts of materials were explored to enhance photothermal efficiency. In the past years, solar-driven desalination by photothermal conversion was proposed to release the shortage of fresh water and then it was considered much more important to prepare photothermal materials on large scales with high performance and low cost. In this review, we summarized the works on carbon-based photothermal materials in the past years, including the preparation as well as their application in steam generation. From these works, we give an outlook on the difficulties and chances of how to design and prepare carbon-based photothermal materials.

Sodium borohydride (NaBH₄) is considered as the most potential hydrogen storage material for portable proton exchange membrane fuel cells (PEMFC) because of its high theoretical hydrogen capacity. However, the slow and poor kinetic stability of hydrogen generation from NaBH₄ hydrolysis limits its application. There are two main factors influencing the kinetics stability of hydrogen generation from NaBH₄. One factor is that the alkaline by-products (NaBO₂) of the hydrolysis reaction can increase the pH of the solution, thus inhibiting the reaction process. It mainly happens in the NaBH₄ solution hydrolysis system. Another factor is that the monotonous increase in reaction temperature leads to uncontrollable and unpredictable hydrolysis rates in the solid NaBH₄ hydrolysis system. This is due to the excess heat generated from this exothermic reaction in the initial reaction of NaBH₄ hydrolysis. In this perspective, we summarize the latest research progress in hydrogen generation from NaBH₄ and emphasize the design principles of catalysts for hydrogen generation from NaBH₄ solution and solid state NaBH₄. The importance of carbon as catalyst support material for NaBH₄ hydrolysis is also highlighted.

Although Mg-based hydrides are extensively considered as a prospective material for solid-state hydrogen storage and clean energy carriers, their high operating temperature and slow kinetics are the main challenges for practical application. Here, a Mg–Ni based hydride, Mg₂NiH₄ nanoparticles (∼100 nm), with dual modification strategies of nanosizing and alloying is successfully prepared via a gas-solid preparation process. It is demonstrated that Mg₂NiH₄ nanoparticles form a unique chain-like structure by oriented stacking and exhibit impressive hydrogen storage performance: it starts to release H₂ at ∼170 °C and completes below 230 °C with a saturated capacity of 3.32 wt% and desorbs 3.14 wt% H₂ within 1800 s at 200 °C. The systematic characterizations of Mg₂NiH₄ nanoparticles at different states reveal the dehydrogenation behavior and demonstrate the excellent structural and hydrogen storage stabilities during the de/hydrogenated process. This research is believed to provide new insights for optimizing the kinetic performance of metal hydrides and novel perspectives for designing highly active and stable hydrogen storage alloys.

At present, there is limited research on the application of fuel cell power generation system technology using solid hydrogen storage materials, especially in hydrogen-assisted two-wheelers. Considering the disadvantages of low hydrogen storage capacity and poor kinetics of hydrogen storage materials, our primary focus is to achieve smooth hydrogen ab-/desorption over a wide temperature range to meet the requirements of fuel cells and their integrated power generation systems. In this paper, the Ti_0.9Zr_0.1Mn_1.45V_0.4Fe_0.15 hydrogen storage alloy was successfully prepared by arc melting. The maximum hydrogen storage capacity reaches 1.89 ​wt% at 318 ​K. The alloy has the capability to absorb 90% of hydrogen storage capacity within 50 ​s at 7 ​MPa and release 90% of hydrogen within 220 ​s. Comsol Multiphysics 6.0 software was used to simulate the hydrogen ab-/desorption processes of the tank. The flow rate of cooling water during hydrogen absorption varied in a gradient of (0.02 ​+ ​x) m s⁻¹ (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.12). Cooling water flow rate is positively correlated with the hydrogen absorption rate but negatively correlated with the cost. When the cooling rate is 0.06 m s⁻¹, both simulation and experimentation have shown that the hydrogen storage tank is capable of steady hydrogen desorption for over 6 h at a flow rate of 2 L min⁻¹. Based on the above conclusions, we have successfully developed a hydrogen-assisted two-wheeler with a range of 80 km and achieved regional demonstration operations in Changzhou and Shaoguan. This paper highlights the achievements of our team in the technological development of fuel cell power generation systems using solid hydrogen storage materials as hydrogen storage carriers and their application in two-wheelers in recent years.