Science China Materials最新文献

Fluorescent probes have revolutionized modern biological research by making it possible to observe and measure an extensive range of cellular and subcellular processes. Among the subcellular compartments, the endoplasmic reticulum (ER) and mitochondria (MT) remain exciting targets owing to the information they reveal about the cellular processes. Consequently, monitoring pH, polarity, viscosity, metal ions, reactive nitrogen species (RNS), reactive sulfur species (RSS) and reactive oxygen species (ROS) in ER and MT with fluorescent probes is of great importance to understand the cellar and subcellular process. Recent years, redox-sensitive probes and ion probes are designed and synthesized for the detection and quantification of RNS/RSS/ROS (collectively as reactive oxygen/nitrogen/sulfur species, RONSS) and metal ions within ER and MT. These probes provide powerful tools for the researchers to learn more about the complex relationship between cellular redox homeostasis and organelle function, and understand the mechanism of disease processes and pathogenesis for developing potential treatments. In this review, the design principles, synthesis methods, targeting mechanism for ER- and MT-targeted RONSS, and metal-ion-specific fluorescent probes are discussed. The recent progress for the synthesis and applications of ER/MT-targeted probes, and their applications for monitoring cellular and subcellular processes are summarized, and the development trends and application prospects of the probes are analyzed.

Environmental pollutants, including gas phase pollutants, liquid organic pollutants, heavy metal ions, and pathogenic bacteria, pose a serious threat to our ecological environment and human health. Effectively addressing these pollutants has become one of the most urgent issues. Graphdiyne (GDY), as an emerging carbon material for environmental remediation, has unique acetylene bonds and abundant pore structures. The unique carbon atomic structure of sp/sp² hybrid endows it with tunable electronic structure and outstanding physical and chemical properties. This review summarizes the practical applications of GDY-based nanomaterials in the context of environmental pollution control, including carbon monoxide (CO) oxidation, ozone (O₃) decomposition, heavy metal ion detection and adsorption, organic pollutant degradation, and bacterial inactivation. Furthermore, the structure-performance relationship of GDY-based nanomaterials is analyzed, and the issues and challenges in the field of environmental remediation of GDY-based materials are indicated.

Hydrogen embrittlement remains a crucial concern in industries that rely on high-strength materials. Exposure to hydrogen poses a significant threat to the mechanical integrity of such materials. This review article briefly discusses the fundamentals of hydrogen embrittlement, including its mechanisms and the effects of various factors, such as chemical composition and environmental conditions. Several heat treatments have been developed to eliminate the risk of hydrogen embrittlement. Among various suggested heat treatments, the retrogression-reaging (RRA) treatment has proven effective in optimizing the balance between mechanical properties and resistance to hydrogen embrittlement. This review highlights the role of RRA treatment in modifying the microstructure of Al-Zn-Mg alloys to enhance their ability to resist hydrogen embrittlement, building on existing literature. An interesting aspect explored in this article is the intricate relationship between pre-deformation and subsequent RRA treatment. Additionally, the review discusses the use of RRA as a post-weld heat treatment to mitigate the susceptibility of weldments to hydrogen embrittlement. A comprehensive exploration of these topics is beneficial for a thorough understanding of the multifaceted functions of RRA treatment. However, despite its advantages, the widespread adoption of RRA treatment in the industry is hindered by certain challenges. This review addresses these challenges, offering insights into the latest strategies to overcome them.

Due to their high capacity, the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion batteries. However, these materials usually exhibit poor electro- chemical properties, resulting from irreversible oxygen redox reactions and phase transition processes at high voltages, and thus hinder their large-scale application. This work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_0.75Li_0.25−2/3xCu_xMn_0.75−1/3x O₂ via Cu doping. Ex-situ XPS demonstrates that Cu doping reduces the amount of Mn³⁺ that triggers the Jahn-Teller effect during the cycling. In addition, the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen, and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between O-O. Meanwhile, in-situ XRD results verify that the Na_0.75Li_0.19Cu_0.09Mn_0.72O₂ maintains the P2 phase structure during charging and discharging, resulting in a near-zero strain characteristic of 1.9%. Therefore, the optimized cathode delivers a high reversible capacity of 194.9 mAh g⁻¹ at 0.1 C and excellent capacity retention of 88.6% after 100 cycles at 5 C. The full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg⁻¹. Our research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.

There are various strategies to conduct tumor microenvironment (TME) stimulus-responsive (e.g., acid, H₂O₂ or glutathione) nanoreactors for increasing the efficiency of chemodynamic therapy (CDT). Among these, the exploitation of adenosine triphosphate (ATP, another over-expressed biomarker in TME)-responsive nanoreactors for tumor CDT is still challenging. Herein, the ATP-responsive iron-doped CDs (FeCDs) were firstly prepared and then co-assembled with glucose oxidase (GOx) to obtain FeCDs/GOx liposomes as ATP-responsive nanoreactors. Under TME conditions, the nanoreactors initially released FeCDs and GOx. Subsequently, with the existence of ATP, iron ions were rapidly released from the FeCDs to trigger Fenton/Fenton-like reactions for generating ·OH. Meanwhile, the T₁-weighted magnetic resonance imaging (MRI) was achieved due to the released iron ions. Moreover, the GOx converted endogenous glucose in tumor to gluconic acid and H₂O₂ to satisfy the requirement of ·OH generation. In vitro as well as in vivo experiments illustrated that the obtained ATP-responsive CD nanoreactors could be used as a versatile nanotheranostics for simultaneously T₁-weighted MRI-guided tumor CDT. This work presents a new ATP-responsive nanoreactor with self-supplied H₂O₂ for multifunctional nanotheranostic applications.

A solar steam evaporator provides a sustainable and efficient alternative water purification solution to address the global freshwater shortage. Previous efforts have made significant advances in maximizing its water evaporation rate, but no single evaporator has all the properties necessary for practical point-of-use application, including a high efficiency for generation of drinkable water, an excellent portability critical for on-site water purification, good washability for mitigating evaporator fouling, and good reusability. We report a strategy to produce a high-performance photothermal material for point-of-use water purification. By simultaneously incorporating graphene and gold particles grown from recycled electronic waste in a mechanically strong sponge, we achieved highly efficient water purification under realistic conditions. In addition to a high evaporation rate (3.55 kg/m²/h under one-sun irradiation) attributed to a control of atomic structure of graphene and the size-dependent surface plasmon resonance of gold nanoparticles, it is portable which can be folded, vacuum compacted, dried and rehydrated without compromising performance. It also allows repeated washing to remove contaminant fouling so that it can be reused. The evaporator transforms various types of contaminated water into drinkable clean water, and can be mounted at any angle to optimize the incident solar irradiation. Furthermore, the assembled steam evaporator device could gain purified water meeting the World Health Organization drinking water standards with a high evaporation rate of 9.36 kg/m²/h under outdoor sunlight.

The development of low-cost, high-performance catalysts at the atomic scale has become a challenging issue for the large-scale applications of renewable clean energy technologies. Herein, on the basis of density functional theory calculation, we systematically investigate the effect of the local environment on the activity and selectivity of electrochemical carbon dioxide reduction reaction over single/multi-atom alloy clusters formed by the transition metal (Fe, Co, and Ni)-doped Cu13/55 clusters. Our findings reveal that the catalytic performance of multi-atom alloy clusters far exceeds that of Cu (211) surface. Notably, the Co666 configuration exhibits exceptional performance with a remarkably low free energy barrier of just 0.33 eV. Furthermore, our investigations demonstrate that catalytic performance is predominantly determined by the relative proportion of modifying metallic dopant species that generate a coordination number of 6. This ratio principally influences the adsorption strength of key intermediates (HCOO* and H₂COO*). Bader charge analyses and free energy calculations elucidate a new mechanistic pathway, wherein the hydrogenation of CO₂ at C-sites catalyzes the reduction of CO₂ to CH₄. This theoretical research provides valuable insights into the fundamental processes and energy landscapes involved in converting CO₂ to CH₄ on the studied catalytic structure, potentially paving the way for more efficient and sustainable carbon dioxide utilization strategies.

Exciplex system is a charming candidate for thermally activated delayed fluorescence (TADF) due to its intrinsic small energy difference between the lowest singlet state and triplet excited state (ΔE_ST). However, high emission efficiency and fast radiative decay rate are still a formidable task for the exciplex emission. Herein two novel tri(triazolo) triazine-based TADF emitters, named TTT-HPh-Ac and TTT-MePh-Ac, are synthesized and characterized. Using such TADF emitters as the donor molecule and (1,3,5-triazine-2,4,6-triyl)tris(benzene-3,1-dial)tris(diphenylphosphine oxide) (PO-T2T) as the acceptor molecule, the exciplex system of TTT-HPh-Ac:PO-T2T and TTT-MePh-Ac:PO-T2T are prepared, which show a tiny ΔE_ST of 40 ± 20 meV and fast reverse intersystem crossing rate. As a result, very high emission efficiency (97%) and a small non-radiative decay rate are detected for the exciplex TADF system. The solution processable organic light-emitting diode using the exciplex system as the emitter achieves a maximum external quantum efficiency (EQE_max) of 17.0%. When using the exciplex as the host matrix, the TTT-MePh-Ac:PO-T2T based solution processable device shows a better performance with an EQE_max of 20% with a very small efficiency roll-off of 6% at 1000 cd m⁻². This work proves that the molecule with both intramolecular hydrogen bonding and proper twisted molecular geometry in exciplex is more favorable to enhance its emission efficiency and suppress the non-radiative transition, which provides a new way to develop efficient and stable exciplex emitters.