Metal-based electrocatalysts with different sizes (single atoms, nanoclusters, and nanoparticles) show different catalytic behaviors for various electrocatalytic reactions. Regulating the ...coordination environment of active sites with precision to rationally design an efficient electrocatalyst is of great significance for boosting electrocatalytic reactions. This review summarizes the recent process of heterogeneous supported single atoms, nanoclusters, and nanoparticles catalysts in electrocatalytic reactions, respectively, and figures out the construct strategies and design concepts based on their strengths and weaknesses. Specifically, four key factors for enhancing electrocatalytic performance, including electronic structure, coordination environment, support property, and interfacial interactions are proposed to provide an overall comprehension to readers in this field. Finally, some insights into the current challenges and future opportunities of the heterogeneous supported electrocatalysts are provided.
Various metal-based electrocatalysts from nanocrystals, to clusters and single-atoms, have been well-discovered towards high-efficient power devices and electrocatalytic conversion. To accelerate ...energy transformation materials discovery, developing high-throughput DFT calculations and machine-learning techniques is of great necessity. This review comprehensively outlines the latest progress of theory-guided design of advanced energy transformation materials. Especially, we focus on the study of single atoms in various power devices, such as fuel cell (oxygen reduction reaction, ORR; acid oxidation reaction; alcohol oxidation reaction), and other reactions for energy-related electrocatalytic conversion of small molecules, such as H2O2 evolution reactions (2e− ORR), water splitting (H2 evolution reaction/O2 evolution reaction, HER/OER), N2 reduction reaction (NRR), and CO2 reduction reactions (CO2RR). Firstly, the electronic structure, interaction mechanism, and reaction activation path are discussed to provide an overall blueprint in electrocatalysis and batteries mentioned above. Thereafter, the experimental synthesis strategies, structural recognition, and electrocatalytic performance for the advanced energy transformation materials are figured out. Finally, some viewpoints into the current issues and future design concept of the advanced energy transformation materials are provided.
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Designing cost‐effective and efficient electrocatalysts plays a pivotal role in advancing the development of electrochemical water splitting for hydrogen generation. Herein, multifunctional ...active‐center‐transferable heterostructured electrocatalysts, platinum/lithium cobalt oxide (Pt/LiCoO2) composites with Pt nanoparticles (Pt NPs) anchored on LiCoO2 nanosheets, are designed towards highly efficient water splitting. In this electrocatalyst system, the active center can be alternatively switched between Pt species and LiCoO2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Specifically, Pt species are the active centers and LiCoO2 acts as the co‐catalyst for HER, whereas the active center transfers to LiCoO2 and Pt turns into the co‐catalyst for OER. The unique architecture of Pt/LiCoO2 heterostructure provides abundant interfaces with favorable electronic structure and coordination environment towards optimal adsorption behavior of reaction intermediates. The 30 % Pt/LiCoO2 heterostructured electrocatalyst delivers low overpotentials of 61 and 285 mV to achieve 10 mA cm−2 for HER and OER in alkaline medium, respectively.
Center of attention: Multifunctional platinum/lithium cobalt oxide (Pt/LiCoO2) heterostructures are prepared that allow the active center to be switched between Pt species for the hydrogen evolution reaction (HER) and LiCoO2 species for the oxygen evolution reaction (OER).
Rational hybridization of two-dimensional (2D) nanomaterials with extrinsic species has shown great promise for a wide range of applications. To date, rational design and engineering of ...heterostructures based on 2D metal–organic frameworks (MOFs) has been rather limited. Herein, we report an efficient strategy to construct noble metal/2D MOF heterostructures, featuring the utilization of surface oxygen sites from uncoordinated MOF ligands. The incorporation of highly dispersed noble metal nanoparticles (e.g., Pt and Pd) with modulated electronic structure is enabled on a surfactant-free MOF surface. As a proof-of-concept demonstration, the 2D Ni-MOF@Pt hybrid with well-defined interfaces is applied to boost the electrochemical hydrogen evolution reaction (HER) and delivers decent electrocatalytic activity under both acidic and alkaline conditions. The present results are expected to provide new insights into furnishing MOFs with extended functionalities and applications.
ABSTRACT
Using the recent 10‐year (March 2000 to February 2010) MODIS data of aerosol optical depth (AOD), the distributions of annual and seasonal mean AOD over China are presented, and the trends ...and seasonal variations in AOD over 10 regions in China are analysed. The spatial pattern of annual mean AOD is characterized generally with two low centres and two high centres over China. Two low AOD centres are located in the areas with a high vegetation cover and a sparse population in (1) the high‐latitude region in Northeast China with AOD of about 0.2 and (2) the high‐altitude region in Southwest China with AOD from 0.1 to 0.2. These two low AOD centres are connected by a low AOD zone (0.2–0.3) in a northeast–southwest direction across China. Demarcated by this low AOD zone, two high centres with AOD of about 0.8 are situated in (1) the most densely populated and industrialized regions in China with high anthropogenic aerosols from North China Plain, Yangtze River areas covering Sichuan Basin, Central China and Yangtze River Delta to South China with Pearl River Delta region and (2) Tarim Basin in Northwest China with high natural aerosols dominated with desert dust. The spatial AOD patterns over China keep seasonally unchanged, but the strengths of the AOD‐centres vary from season to season. The wintertime AOD is lowest in China. The monthly AOD variations from March to September in Southern China correspond with high AOD before, after the rain periods and low AOD during the rain periods of Asian summer monsoon. Asian summer monsoons also make a notable impact on the seasonal cycle of aerosols in China. The AOD in Northern China changes monthly with a single peak between April and June and a low in the winter months. The positive trends in AOD occur mostly in the aerosol source regions with higher annual mean AOD (>0.25), while the negative trends are found in the regions with lower annual mean AOD (<0.25) over China.
Targeting the KRAS pathway is a promising but challenging approach for colorectal cancer therapy. Despite showing potent efficacy in BRAF-mutated melanoma, MEK inhibitors appeared to be tolerated by ...colorectal cancer cells due to their intrinsic compensatory signaling. Here, we performed genome-wide CRISPR/Cas9 screening in the presence of MEK inhibitor to identify genes that are synthetically lethal with MEK inhibition in CRC models harboring KRAS mutations. Several genes were identified as potential functional drivers, which were significantly enriched in the GRB7-mediated RTK pathway. Loss-of-function and gain-of-function assays validated that GRB7 potently rendered CRC cells primary resistance to MEK inhibitors through the RTK pathway. Mass spectrum analysis of GRB7 immunoprecipitates revealed that PLK1 was the predominant interacting kinase of GRB7. Inhibition of PLK1 suppressed downstream signaling of RTK, including FAK, STAT3, AKT, and 4EBP1. The combination of PLK1 and MEK inhibitors synergistically inhibited CRC cell proliferation and induced apoptosis in vitro and in vivo. In conclusion, we identified GRB7-PLK1 as a pivotal axis mediating RTKs, resulting in MEK inhibitor tolerance. PLK1 is therefore a promising target for synergizing MEK inhibitors in the clinical treatment of CRC patients harboring KRAS mutations.
Quantum key distribution uses the principle of quantum physics to realize unconditionally secure key distribution protocol. But this kind of security needs to be based on the authenticated classical ...channel. Although there are quantum key distribution protocols without classical channel, authentication is still needed. In the process of key distribution, authentication is not considered, which is also a problem of quantum key distribution protocol. In this paper, a quantum key distribution protocol with two-way authentication is proposed. Identity authentication is carried out at the same time of key distribution. If the identity authentication fails, the key distribution protocol cannot be carried out. If the key distribution protocol is aborted, the identity authentication is not successful. The conclusion of this paper is based on a central authentication system supported by symmetric encryption theory, which uses pseudo-random functions, multiple sets of quantum conjugate bases and Measurement-device-independent technology to simultaneously achieve two-way authentication and key distribution.
Poor storage property and the rapid moisture hinder the application of LiNi0.8Co0.1Mn0.1O2 due to the formation of Li2CO3/LiOH impurities and a spontaneous reduction of Ni3+ to Ni2+ on the surface. ...Alcohol washing is desirable to improve the electrochemical performance, storage characteristics and structural stability of LiNi0.8Co0.1Mn0.1O2. Electrochemical studies indicate that washed material exhibits a higher discharge capacity (148mAhg−1 at 8C) and better capacity retention at 2C (79.2% after 100 cycles) compared with the un-treated material after storage in air for 40 days. Inductively coupled plasma (ICP) tests show the amount of metal dissolution decreases compared with the un-washed sample. The Rietveld refinement results indicate that the Li/Ni cationic disorder can be reduced from 0.0714 to 0.0538 by alcohol washing after storage. Transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) indicate alcohol washing contributes LiNi0.8Co0.1Mn0.1O2 much resistant to H2O and CO2, which further reduce the formation of Li2CO3 and maintain structural stability during the storage process.
Cancer stem cells (CSCs) are a minority subset of cancer cells that can drive tumor initiation, promote tumor progression, and induce drug resistance. CSCs are difficult to eliminate by conventional ...therapies and eventually mediate tumor relapse and metastasis. Moreover, recent studies have shown that CSCs display plasticity that renders them to alter their phenotype and function. Consequently, the varied phenotypes result in varied tumorigenesis, dissemination, and drug-resistance potential, thereby adding to the complexity of tumor heterogeneity and further challenging clinical management of cancers. In recent years, tumor microenvironment (TME) has become a hotspot in cancer research owing to its successful application in clinical tumor immunotherapy. Notably, emerging evidence shows that the TME is involved in regulating CSC plasticity. TME can activate stemness pathways and promote immune escape through cytokines and exosomes secreted by immune cells or stromal cells, thereby inducing non-CSCs to acquire CSC properties and increasing CSC plasticity. However, the relationship between TME and plasticity of CSCs remains poorly understood. In this review, we discuss the emerging investigations on TME and CSC plasticity to illustrate the underlying mechanisms and potential implications in suppressing cancer progression and drug resistance. We consider that this review can help develop novel therapeutic strategies by taking into account the interlink between TME and CSC plasticity.
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