材料导报:能源(英文)最新文献

Single atom catalysts (SACs) are constituted by isolated active metal centers, which are heterogenized on inert supports such as graphene, porous carbon, and amorphous carbon. The thermal stability, electronic properties, and catalytic activities of the metal center can be controlled via manipulating the neighboring heteroatoms such as nitrogen, oxygen, and sulfur. Due to the atomical dispersion of the active catalytic centers, the amount of metal required for catalysis can be decreased. Furthermore, new possibilities are offered to easily control the selectivity of a given transformation process as well as to improve turnover frequencies and turnover numbers of target reactions. Among them, Fe–N–C single atom catalysts own special electronic structure, and have been widely used in many fields of electrocatalysis. This review aims to summarize the synthesis of Fe–N–C based on anchoring individual iron atoms on carbon/graphene. The spin-related properties of Fe–N–C catalysts are described, including the relation between spin and electron structure of Fe–N_x as well as the coupling between electronic structure of Fe–N_x and electronic (orbit) of CO₂, N₂ and O₂. Next, mechanistic investigations conducted to understand the specific behavior of Fe–N–C catalysts are highlighted, including C, N, O electro-reduction. Finally, some issues related to the future developments of Fe–N–C are put forward and corresponding feasible solutions are offered.

Developing isolated single atomic noble metal catalysts is one of the most effective methods to maximize noble metal atom utilization efficiency and enhance catalytic performances. Layered double hydroxides (LDHs) are two-dimensional nanoarchitectures in which M³⁺ and M²⁺ sites are atomically isolated due to static repulsions, providing special anchoring sites for single noble metal atoms and enabling the tuning of catalytic activity. Herein, a comprehensive review of the advances in LDHs supported single-atom catalysts (M/LDH SACs) is presented, focusing on the synthetic strategies, structure characterization, and application of M/LDH SACs in energy devices. Strong electronic coupling between single atomic noble metal atoms and corresponding anchoring sites of LDHs determines not only the catalytic activity of M/LDH SACs but also the stability during catalytic reactions. Furthermore, a perspective is proposed to highlight the challenges and opportunities for understanding the reaction mechanism and development of highly efficient M/LDH SACs.

The conversion of carbon dioxide (CO₂) into high-value added energy fuels and chemicals (CO, formate, C₂H₄, etc.) through electrochemical reduction (eCO₂R) is a promising avenue to sustainable development. However, low selectivity, barren activity and poor stability of the electrodes hinder the large-scale application of eCO₂R. Herein, we reported a copper-indium-organic-framework (CuIn-MOF) based high-performance catalyst for eCO₂R. Electrochemical measurement results reveal that CuIn-MOF exhibits high Faradaic efficiency (FE) of CO and formate (300 mV, FE_CO = 78.6% at −0.86 V vs. RHE, FE_HCOO⁻ = 48.4% at −1.16 V vs. RHE, respectively) in a broad range of current density (20.1–88.4 mA cm⁻²) with long-term stability (6 h) for eCO₂R in 0.5 M KHCO₃ electrolyte solution. Specifically, through anion-regulation engineering, SO₄²⁻ anion precursor is more beneficial for the formic acid generation than NO₃⁻ anion precursor; while for SO₄²⁻ anion precursor, Cu plays a positive regulating role in eCO₂R to CO compared to In. Additionally, the high performance in a home-made eCO₂R reactor derives benefit from enhanced intrinsic activity and charge re-distribution can be attributed to the formation of In-doped Cu layer.

Aqueous rechargeable lithium-ion battery (ARLiB) is of specific importance due to the low-cost, environmental-friendly properties. Recently, its energy denisty and cyclic life have been significantly enhanced, demonstarting the potential for real applications. The improvement on key materials of ARLiB, ranging from cathode, anode and electrolyte, can finally ameliorate coresponding performance of full cell. Hereon, the cathode materials of ARLiBs are summerized as spinel oxides, layered oxides, olivine polyanion compounds olivine and Prussian blue analogues, while anode materials are classified into vanadium-based, polyanion, titanium-based and organic ones. Meanwhile, the strategies for better aqueous electrolytes are discussed from the aspects of salt concentration, solvent and interface. In the last part, issues challenging the commercialization of ARLiBs are provided as well as the suggestions for future research and development.

The present work explores the application of La_0.5Sr_0.5Co_0.95Nb_0.05O_3-δ (LSCNO) perovskite as electrode material for the symmetric solid oxide fuel cell. Symmetric solid oxide fuel cells of thin-film LSCNO electrodes were prepared to study the oxygen reduction reaction at intermediate temperature. The Rietveld refinement of synthesized material shows a hexagonal structure with the R-3c space group of the prepared perovskite material. Lattice parameter and fractional coordinates were utilized to calculate the oxygen ion diffusion coefficient for molecular dynamic simulation. At 973 K, the oxygen ion diffusion of LSCNO was 1.407 $\times$ 10⁻⁸ cm² s⁻¹ higher by order of one magnitude than that of the La_0.5Sr_0.5CoO_3-δ (7.751 $\times$ 10⁻⁹ cm² s⁻¹). The results suggest that the Nb doping provide the structural stability which improves oxygen anion diffusion. The enhanced structural stability was analysed by the thermal expansion coefficient calculated experimentally and from molecular dynamics simulations. Furthermore, the density functional theory calculation revealed the role of Nb dopant for oxygen vacancy formation energy at Sr–O and La–O planes is lower than the undoped structure. To understand the rate-limiting process for sluggish oxygen diffusion kinetics, 80 nm and 40 nm thin films were fabricated using radio frequency magnetron sputtering on gadolinium doped ceria electrolyte substrate. The impedance was observed to increase with an increasing thickness, suggesting the bulk diffusion as a rate-limiting step for oxygen ion diffusion. The electrochemical performance was analysed for the thin-film symmetric solid oxide fuel cell, which achieved a peak power density of 390 mW cm⁻² at 1.02 V in the presence of H₂ fuel on the anode side and air on the cathode side.

Redox flow batteries have received wide attention for electrochemical energy conversion and storage devices due to their specific advantage of uncoupled power and energy devices, and therefore potentially to reduce the capital costs of energy storage. Terrific structural features of polyoxometalates exhibit unique advantages in redox flow batteries, such as, stable chemical properties, multi-electron reaction, good redox reversibility, low permeability, etc, which furnishes a novel perspective for settling various problems of redox flow batteries. This was a comprehensive and critical review of this type of batteries, focusing mainly on the chemistry of polyoxometalate electrolyte materials and introducing a systematic classification. Finally, challenges and perspectives of polyoxometalate electrolyte materials and polyoxometalate redox flow batteries are discussed.

Glucose fuel cells (GFCs) driven by abiotic catalysts are promising green power sources for portable or wearable devices. In this work, a CoO_x incorporated carbon nanofiber (CoO_x@CNF) catalyst with mixed valences cobalt oxides have been developed through partial oxidation of pyrolyzed electrospun Co²⁺/poly acrylonitrile fibers. The cobalt valence modulating could be achieved via regulating the incorporation ratio of cobalt acetate in precursors or the oxidation temperature of the pyrolyzed fibers. Electrocatalytic analyses show that the presence of CoO in CoO_x@CNF will provide more active sites for glucose electrooxidation, and thus enhance the electrocatalytic performance significantly. As a result, the glucose fuel cell built with the CoO_x@CNF anode containing both CoO and Co₃O₄ delivered a maximum power density of 270 μW cm⁻², which is higher than that of other reported Co₃O₄ based GFCs. This work provides a simple strategy to develop excellent transition metal catalysts for GFCs to expand their applications in portable and wearable energy devices.

Electrochemical water splitting has been demonstrated as a promising technology for the renewable generation of green hydrogen from water. Despite the extensive progress in materials science, one particular challenge for further development towards industrial application lies in the rational design and exploitation of efficient and cost-effective materials, especially oxygen evolution reaction (OER) electrocatalysts at the anode. In addition, attempts to replace the OER with other more oxidizable anode reactions are being evaluated as a groundbreaking strategy for generating hydrogen at lower potentials and reducing overall energy costs while producing valuable chemicals simultaneously. Compared with Fe/Co/Ni-based compounds, Cu-based materials have not received extensive research attention for electrode designs despite their high conductivity and abundant earth reserves. In this review, combining with the advantages of a three-dimensional network structure of metal foams, we summarize recent progress on Cu foam (CF)-derived materials as efficient electrocatalysts towards pure water electrolysis and hybrid water electrolysis. The advantages of CF and design strategies to enhance the electrocatalytic activity and operational durability are presented first. Catalyst design and fabrication strategies are then highlighted and the structure-activity relationship is also discussed. Finally, we propose challenges and perspectives on self-supported electrodes beyond CF-derived materials.