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Developing high-performance electrocatalysts toward hydrogen evolution reaction is important for clean and sustainable hydrogen energy, yet still challenging. Herein, we report a single-atom strategy to construct excellent metal-organic frameworks (MOFs) hydrogen evolution reaction electrocatalyst (NiRu 0.13 -BDC) by introducing atomically dispersed Ru. Significantly, the obtained NiRu 0.13 -BDC exhibits outstanding hydrogen evolution activity in all pH, especially with a low overpotential of 36 mV at a current density of 10 mA cm −2 in 1 M phosphate buffered saline solution, which is comparable to commercial Pt/C. X-ray absorption fine structures and the density functional theory calculations reveal that introducing Ru single-atom can modulate electronic structure of metal center in the MOF, leading to the optimization of binding strength for H 2 O and H*, and the enhancement of HER performance. This work establishes single-atom strategy as an efficient approach to modulate electronic structure of MOFs for catalyst design. Developing high-performance, neutral-media H 2 -evolution electrocatalysts is important for clean and sustainable hydrogen energy, yet rare, expensive elements are most active. Here, authors show that metal-organic frameworks modified with single ruthenium atoms as high-performances catalysts.

Metal-organic frameworks (MOFs) have been recognized as compelling platforms for the development of miscellaneous applications because of their structural diversity and functional tunability. Here, we propose that the electrocatalytic properties could be well modified by incorporating missing linkers into the MOF. Theoretical calculations suggest the electronic structure of MOFs can be tuned by introducing missing linkers, which improves oxygen evolution reaction (OER) performance of the MOF. Inspired by these aspects, we introduced various missing linkers into a layered-pillared MOF Co 2 (OH) 2 (C 8 H 4 O 4 ) (termed as CoBDC) to prepare missing-linker MOFs. Transmission electron microscope and synchrotron X-ray measurements confirmed that the missing linkers in the MOF could be introduced and well controlled by our strategy. The self-supported MOF nanoarrays with missing linkers of carboxyferrocene exhibit excellent OER performance with ultralow overpotential of 241 mV at 100 mA cm −2 . This work opens a new prospect to develop efficient MOF-based electrocatalysts by introducing missing linkers. While water splitting electrocatalysis provides a means to store electrical energy as fuel, the water oxidation catalysts typically show low performances. Here, authors employ metal-organic frameworks with missing-linkers as highly active oxygen evolution electrocatalysts.

Development of fifth‐generation technology leads to a growing demand for materials with exceptional thermal property, mechanical strength, and low dielectric loss. However, ensuring the broad application of such materials by comprehensively investigating their aging mechanisms and service lifetimes remains a challenge. In this work, we have developed a glass fiber (GF) reinforced liquid crystal polymer composite (GF/LCP) and conducted a thorough exploration of its aging mechanism, behavior, and service lifetime under thermal and oxidative conditions. On the basis of the general Arrhenius model, the composite maintains a high level of functionality for a remarkable 18 years at 150 °C and 1.5 years at 200 °C. Despite the extremely high thermal resistance of GF/LCP composite, the LCP matrix exhibits localized brittle fracture, and the main chains still undergo gradual degradation to generate phenolic groups, which ultimately leads to severe pulverization and mass loss. However, a high degree of connection maintenance between GF and LCP components is still reserved. This work provides a valuable reference for the reliable application of 5G materials under thermal and oxidative conditions. A kind of glass fiber (GF) reinforced liquid crystal polymer (GF/LCP) composite and comprehensively investigated its aging behavior, mechanism, and service lifetime under long‐term thermal and oxidative conditions. Assisted by the general Arrhenius model, the composite maintained a high level of quality for 18 years at 150 °C. The aging mechanism was deeply investigated.

The development of fifth‐generation technology has resulted in increased demand for materials with low dielectric losses and superior thermal and mechanical properties. However, ensuring the widespread use of such materials by investigating their aging mechanisms and operating lifetimes remains challenging. In this study, a glass‐fiber (GF)‐reinforced acrylate‐styrene‐acrylonitrile/polycarbonate (ASA/GF/PC) composite is designed and comprehensively investigated its aging behavior, mechanism, and service lifetime under long‐term hygrothermal conditions. Based on the general Peck model, the composite maintains a high level of quality for over 10 years, including under harsh conditions of 40 °C and 80% relative humidity. The aging mechanism is primarily ascribed to cracking between the GF fibers and matrix, the breaking of chemical bonds, the generation of new cross‐linked domains, and physical aging. These findings provide valuable insights into the long‐term utilization of ASA/GF/PC composites in harsh environments. A kind of glass fiber (GF) reinforced acrylate‐styrene‐acrylonitrile/polycarbonate (ASA/GF/PC) composite and comprehensively investigated its aging behavior, mechanism, and service lifetime under long‐term hygrothermal conditions. Assisted by the general Peck model, the composite maintains a high level of quality for over 10 years, even under harsh conditions of 40 °C and 80% relative humidity.

GaN-based terahertz (THz) Schottky barrier diodes (SBDs) are critical components for achieving high-power performance in THz frequency multipliers. However, the space applications of GaN-based THz SBDs are significantly constrained due to insufficient research on the effects of space irradiation. This work investigates the effects of 450 MeV Kr swift heavy ion (SHI) irradiation on the electrical characteristics and induced defects in GaN-based THz SBDs. It was found that the high-frequency performance of GaN-based THz SBDs is highly sensitive to Kr SHI irradiation, which can be attributed to defects induced in the GaN epitaxial layer by the irradiation. Low-frequency noise analysis reveals trap states located at an energy level of approximately 0.62 eV below the conduction band. Moreover, the results from SRIM calculation and photoluminescence spectra confirmed the presence of irradiation-induced defects caused by Kr SHI irradiation.

The exploration of novel porous core–shell materials is of great significance because of their prospectively improved performance and extensive applications in separation, energy conversion, and catalysis. Here, mesoporous metal–organic frameworks (MOFs) NH2‐MIL‐101(Fe) as a core generate a shell with mesoporous covalent organic frameworks (COFs) NUT‐COF‐1(NTU) by a covalent linking process, the composite NH2‐MIL‐101(Fe)@NTU keeping retentive crystallinity with hierarchical porosity well. Importantly, the NH2‐MIL‐101(Fe)@NTU composite shows significantly enhanced catalytic conversion and selectivity during styrene oxidation. It is mainly due to the hydrophilic MOF nanocrystals readily gathering the hydrophobic reactants styrene and boosting the radical mechanism path after combining the hydrophobic COFs shell. The synthetic strategy in this systematic study develops a new rational design for the synthesis of other core–shell MOF/COF‐based hybrid materials, which can expand the promising applications. A hydrophobic core–shell hybrid is synthesized by metal–organic frameworks NH2‐MIL‐101(Fe) as the core and covalent organic frameworks (COFs) NTU‐COF‐1 (NTU) as the shell via a covalent linking process. Importantly, NH2‐MIL‐101(Fe)@NTU composites show significantly enhanced catalytic conversion and selectivity during the styrene oxidation.

The polarizer film is an important component in the Thin-film-transistor liquid crystal displays (TFT-LCDs), which is a multilayer composite film developed by using dichromatic material stretching film technology. However, the polarizer film is liable to fail in hygrothermal circumstances. In this work, we analyzed a polarizer film shipped from China to Brazil that failed due to the ocean environment. By analyzing the structure, composition, and crystallinity of the polarizer film, Polyvinyl Alcohol (PVA) layer of the polarizer film has larger crystallinity, and there are bonding pores between the PVA layer and the Triacetyl Cellulose (TAC) layer. Under the action of the marine environment, the I3− ions in the PVA layer were released, resulting in the separation of PVA layer and TAC layer at the bonding pores, and then forming bright spots. Furthermore, through analyzing the marine environment and simulated environmental experiments, it was determined that the thermal environmental factor induces the release of I3− ions in the PVA layer. Finally, based on the failure process and failure mechanism of the polarizer, improvement measures to prevent the occurrence of bright spots of the polarizer are proposed.

Materials with lower dielectric loss and greater thermal and mechanical properties have drawn public attention with the rapid development of 5G technology. However, the mastery and understanding of the aging mechanism and working lifetime of these specific materials remain an open challenge. Here, we designed a glass fiber (GF)-reinforced acrylate–styrene–acrylonitrile/polycarbonate (ASA/GF/PC) composite and systematically investigated its aging behavior, aging mechanism, and lifetime prediction under long-term thermal and oxidative conditions. The aging behaviors regarding the mechanical, dielectric properties and color change were deeply analyzed at four aging temperatures. Results indicated that impact strength was applicable to estimate working lifetime. Assisted by general Arrhenius kinetic models, the predicted lifetimes were 22,334 days at 303 K, 8605 days at 313 K, 3517 days at 323 K, and 1516 days at 333 K, respectively. The study of aging mechanism confirmed that thermal degradation inevitably occurred in the ASA and PC phases, which provoked the appearance of newborn oxygen-containing groups and further induced the generation of cross-linked domains. The desired results provide a valuable reference to guide the widespread and long-term utilization of ASA/GF/PC composites in 5G technology.

This study describes a comparative investigation on the heterogeneous versus homogeneous nature of the Pd‐catalyzed Suzuki–Miyaura cross‐coupling reaction mechanism with specific magnetic hierarchical core–shell and yolk–shell structures. The hierarchical core–shell Fe3O4@SiO2‐Pd@mCeO2 (m=mesoporous) catalyst contains a core of nonporous silica‐sheltered magnetite (Fe3O4) nanoparticles (NPs), a transition layer of active palladium (Pd) NPs, and an outer shell of porous ceria (CeO2). The magnetic yolk–shell Fe3O4@h‐Pd@mCeO2 (h=hollow) catalyst was prepared by selectively etching the nonporous silica interlayers. Notably, the results of the hot‐filtration heterogeneity test, the effect of Pd concentration, and solid‐phase poisoning, indicate that the two kinds of catalysts function in Pd‐catalyzed Suzuki–Miyaura cross‐coupling reactions through different catalytic mechanisms. Moreover, both catalysts demonstrated better catalytic activity than the Fe3O4@SiO2‐Pd catalyst. This finding can be ascribed to the outermost CeO2 shell having a high concentration of trivalent cerium and oxygen vacancies, which gives rise to the increased electron density of Pd NPs, and a faster rate‐determining step in the oxidative addition reaction for the Suzuki reaction. In addition, we propose a feasible mechanism elucidating the synergistic effect between the supporting CeO2 and active species. Delving deeper: Two different catalysts having magnetic hierarchical core–shell and yolk–shell structures (see figure) are compared in terms of their reaction mechanisms for the Pd‐catalyzed Suzuki–Miyaura cross‐coupling reaction mechanism.