Two dimensional nanoarchitectures are of great interest in lithium storage for energy‐storage devices, in particular lithium‐ion batteries, due to its shortened paths for fast lithium ion diffusion ...and large exposed surface offering more lithium‐insertion channels. Their competitive lithium‐storage features provide huge potentials to develop next‐generation high‐performance lithium‐ion batteries. This review is devoted to the recent progress in the fabrication of innovative 2D structures with various synthetic strategies and their applications for lithium storage in lithium‐ion batteries. These 2D architectures are categorized into six styles, i.e., nanoporous nanosheets, ultrathin nanosheets, flower‐like structures assembled by nanosheets, sandwich‐like nanosheets, corrugated nanosheets, and nanosheets with specific facets. Based on the lithium‐storage manner, we further summerized their electrochemical performance for lithium storage with four classified themes including surface Li storage, zero or low‐strain Li storage, volume‐variation Li storage and synergic‐effect Li storage. Finally, the outlook and perspective on 2D lithium‐storage materials is concisely provided.
Inspired by nature, this review is devoted to the recent progress in the fabrication of novel 2D structures and their lithium‐storage performance. We herein present a comprehensive overview of six kinds of novel 2D nanostructures in view of their structures obtained with various synthetic strategies. Moreover, the lithium‐storage capabilities of 2D architectures are categorized by four themes based on the Li‐insertion method.
Layered double hydroxides (LDHs) are among the most active and studied catalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. However, previous studies have generally either ...focused on a small number of LDHs, applied synthetic routes with limited structural control, or used non‐intrinsic activity metrics, thus hampering the construction of consistent structure–activity‐relations. Herein, by employing new individually developed synthesis strategies with atomic structural control, we obtained a broad series of crystalline α‐MA(II)MB(III) LDH and β‐MA(OH)2 electrocatalysts (MA=Ni, Co, and MB=Co, Fe, Mn). We further derived their intrinsic activity through electrochemical active surface area normalization, yielding the trend NiFe LDH > CoFe LDH > Fe‐free Co‐containing catalysts > Fe‐Co‐free Ni‐based catalysts. Our theoretical reactivity analysis revealed that these intrinsic activity trends originate from the dual‐metal‐site nature of the reaction centers, which lead to composition‐dependent synergies and diverse scaling relationships that may be used to design catalysts with improved performance.
Catalytic activities for oxygen evolution on crystalline 3d transition metal layered double hydroxides are derived using electrochemical surface area based normalization. Density functional calculations reveal a dual‐metal‐site feature of the reaction centers that provides opportunities to design new catalysts with improved performance.
A central goal of neuroscience is to understand the representations formed by brain activity patterns and their connection to behaviour. The classic approach is to investigate how individual neurons ...encode stimuli and how their tuning determines the fidelity of the neural representation. Tuning analyses often use the Fisher information to characterize the sensitivity of neural responses to small changes of the stimulus. In recent decades, measurements of large populations of neurons have motivated a complementary approach, which focuses on the information available to linear decoders. The decodable information is captured by the geometry of the representational patterns in the multivariate response space. Here we review neural tuning and representational geometry with the goal of clarifying the relationship between them. The tuning induces the geometry, but different sets of tuned neurons can induce the same geometry. The geometry determines the Fisher information, the mutual information and the behavioural performance of an ideal observer in a range of psychophysical tasks. We argue that future studies can benefit from considering both tuning and geometry to understand neural codes and reveal the connections between stimuli, brain activity and behaviour.
The ubiquitin‐proteasome system (UPS) is a rapid regulatory mechanism for selective protein degradation in plants and plays crucial roles in growth and development. There is increasing evidence that ...the UPS is also an integral part of plant adaptation to environmental stress, such as drought, salinity, cold, nutrient deprivation and pathogens. This review focuses on recent studies illustrating the important functions of the UPS components E2s, E3s and subunits of the proteasome and describes the regulation of proteasome activity during plant responses to environment stimuli. The future research hotspots and the potential for utilization of the UPS to improve plant tolerance to stress are discussed.
The ubiquitin‐proteasome system (UPS) plays crucial roles in plant responses to environment stimuli through degrading distinct target proteins. This review summaries recent progress in our understanding of the regulation of UPS components, subunits and proteasome activity under abiotic and biotic stress, and future research hotspots are discussed.
Abstract
Supported metal nanoparticles are of universal importance in many industrial catalytic processes. Unfortunately, deactivation of supported metal catalysts via thermally induced sintering is ...a major concern especially for high-temperature reactions. Here, we demonstrate that the particle distance as an inherent parameter plays a pivotal role in catalyst sintering. We employ carbon black supported platinum for the model study, in which the particle distance is well controlled by changing platinum loading and carbon black supports with varied surface areas. Accordingly, we quantify a critical particle distance of platinum nanoparticles on carbon supports, over which the sintering can be mitigated greatly up to 900 °C. Based on in-situ aberration-corrected high-angle annular dark-field scanning transmission electron and theoretical studies, we find that enlarging particle distance to over the critical distance suppress the particle coalescence, and the critical particle distance itself depends sensitively on the strength of metal-support interactions.
The active site of the industrial Cu/ZnO/Al2O3 catalyst used in CO2 hydrogenation to methanol has been debated for decades. Grand challenges remain in the characterization of structure, composition, ...and chemical state, both microscopically and spectroscopically, and complete theoretical calculations are limited when it comes to describing the intrinsic activity of the catalyst over the diverse range of structures that emerge under realistic conditions. Here a series of inverse model catalysts of ZnO on copper hydroxide were prepared where the size of ZnO was precisely tuned from atomically dispersed species to nanoparticles using atomic layer deposition. ZnO decoration boosted methanol formation to a rate of 877 gMeOH kgcat−1 h−1 with ≈80 % selectivity at 493 K. High pressure in situ X‐ray absorption spectroscopy demonstrated that the atomically dispersed ZnO species are prone to aggregate at oxygen‐deficient ZnO ensembles instead of forming CuZn metal alloys. By modeling various potential active structures, density functional theory calculations and microkinetic simulations revealed that ZnO/Cu interfaces with oxygen vacancies, rather than stoichiometric interfaces, Cu and CuZn alloys were essential to catalytic activation.
High‐pressure in situ X‐ray absorption spectroscopy disclosed the structure evolution of isolated Zn species to oxygen‐deficient ZnO ensembles on an atomically dispersed ZnO/Cu catalyst during methanol synthesis from CO2. Density functional theory calculations further revealed that oxygen vacancies at the interfaces play an important role in the active site.
Accurate tool condition monitoring (TCM) is essential for the development of fully automated milling processes. However, while considerable research has been conducted in industrial and academic ...settings, the complexity of milling processes continues to complicate the implementation of TCM. This paper presents a review of the state-of-the-art methods employed for conducting TCM in milling processes. The review includes three key components: (1) sensors, (2) feature extraction, and (3) monitoring models for the categorization of cutting tool states in the decision-making process. In addition, the primary strengths and weaknesses of current practices are presented for these three components. Finally, this paper concludes with a list of recommendations for future research.
As a 100% atom-economy process, direct oxidation of methane into methanol remains as a grand challenge due to the dilemma between activation of methane and over-oxidation of methanol. Here, we report ...that water enabled mild oxidation of methane into methanol with >99% selectivity over Au single atoms on black phosphorus (Au
/BP) nanosheets under light irradiation. The mass activity of Au
/BP nanosheets reached 113.5 μmol g
in water pressured with 33 bar of mixed gas (CH
:O
= 10:1) at 90 °C under light irradiation (1.2 W), while the activation energy was 43.4 kJ mol
. Mechanistic studies revealed that water assisted the activation of O
to generate reactive hydroxyl groups and •OH radicals under light irradiation. Hydroxyl groups reacted with methane at Au single atoms to form water and CH
* species, followed by oxidation of CH
* via •OH radicals into methanol. Considering the recycling of water during the whole process, we can also regard water as a catalyst.
NiFe and CoFe (MFe) layered double hydroxides (LDHs) are among the most active electrocatalysts for the alkaline oxygen evolution reaction (OER). Herein, we combine electrochemical measurements, ...operando X-ray scattering and absorption spectroscopy, and density functional theory (DFT) calculations to elucidate the catalytically active phase, reaction center and the OER mechanism. We provide the first direct atomic-scale evidence that, under applied anodic potentials, MFe LDHs oxidize from as-prepared α-phases to activated γ-phases. The OER-active γ-phases are characterized by about 8% contraction of the lattice spacing and switching of the intercalated ions. DFT calculations reveal that the OER proceeds via a Mars van Krevelen mechanism. The flexible electronic structure of the surface Fe sites, and their synergy with nearest-neighbor M sites through formation of O-bridged Fe-M reaction centers, stabilize OER intermediates that are unfavorable on pure M-M centers and single Fe sites, fundamentally accounting for the high catalytic activity of MFe LDHs.
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