RESUMO
This study aimed to investigate the expression of SF3B1 in non-small cell lung cancer, and its clinical significance, biological function, and molecular mechanisms. SF3B1 mRNA and protein levels were elevated in both lung squamous cell carcinoma and lung adenocarcinoma (LUAD) tissues based on TCGA data and immunohistochemistry. Notably, high SF3B1 expression in LUAD was significantly associated with increased lymph node metastasis. Functional experiments involving SF3B1 knockdown and overexpression demonstrated that SF3B1 facilitated the proliferation, invasion, and migration of LUAD cells. Additionally, the SF3B1 inhibitor pladienolide-B attenuated the aggressive behavior of LUAD cells both in vitro and in vivo. RNA sequencing analysis indicated that differentially expressed genes in the SF3B1 knockdown and SF3B1 inhibitor groups were enriched in ferroptosis-related pathways compared to their respective control groups. The antiferroptotic role of SF3B1 in LUAD cells was validated by detecting glutathione depletion, lipid peroxidation, and observing morphological changes using transmission electron microscopy. This process was confirmed to be independent of apoptosis and autophagy, as evidenced by the effects of the ferroptosis inducer erastin, the apoptosis inhibitor Z-VAD-FMK, and the autophagy inhibitor 3-methyladenine. Rescue experiments indicated that the antiferroptotic role of SF3B1 in LUAD is partially mediated by upregulating the expression of SLC7A11.
RESUMO
Objectives: To identify the long-term spatiotemporal trend of ozone-related chronic obstructive pulmonary disease (COPD) burden by sex and country and to explore potential drivers. Methods: We retrieved data of ozone-related COPD death and disability adjusted life year (DALY) from the Global Burden of Disease 2019. We used a linear regression of natural logarithms of age-standardized rates (ASRs) with calendar year to examine the trends in ASRs and a panel regression to identify country-level factors associated with the trends. Results: Global ozone-attributable COPD deaths increased from 117,114 to 208,342 among men and from 90,265 to 156,880 among women between 1990 and 2019. Although ASRs of ozone-related COPD death and DALY declined globally, they increased in low and low-middle Socio-demographic Index (SDI) regions, with faster rise in women. Elevated average maximum temperature was associated with higher ozone-attributable COPD burden, while more green space was associated with lower burden. Conclusion: More efforts are needed in low and low-middle SDI regions, particularly for women, to diminish inter-country inequality in ozone-attributable COPD. Global warming may exacerbate the burden. Expanding green space may mitigate the burden.
Assuntos
Carga Global da Doença , Saúde Global , Ozônio , Doença Pulmonar Obstrutiva Crônica , Humanos , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Ozônio/efeitos adversos , Feminino , Masculino , Análise Espaço-Temporal , Pessoa de Meia-Idade , Idoso , Anos de Vida Ajustados por Deficiência , Poluentes Atmosféricos/efeitos adversos , Exposição Ambiental/efeitos adversos , Fatores Sexuais , Poluição do Ar/efeitos adversosRESUMO
OBJECTIVE: This study evaluates intratympanic lidocaine's efficacy and safety for tinnitus relief in sudden sensorineural hearing loss (SSNHL) patients. METHODS: In a double-blind randomized controlled trial, 100 SSNHL patients with unilateral tinnitus received either intratympanic lidocaine or saline plus usual care. Treatment impact was assessed at 1 and 3 months using the Tinnitus Handicap Inventory, subjective visual analog scale, pure-tone audiometry. RESULTS: The lidocaine group demonstrated significant tinnitus relief according to the Tinnitus Handicap Inventory and visual analog scale, without pure-tone audiometry improvement or serious adverse events throughout the study period. CONCLUSION: Intratympanic lidocaine provides a safe, efficacious treatment option for SSNHL tinnitus. Further studies should refine the dosage and delivery parameters because of SSNHL's heterogenous nature.
Assuntos
Anestésicos Locais , Audiometria de Tons Puros , Perda Auditiva Neurossensorial , Perda Auditiva Súbita , Injeção Intratimpânica , Lidocaína , Zumbido , Humanos , Zumbido/tratamento farmacológico , Método Duplo-Cego , Masculino , Feminino , Lidocaína/administração & dosagem , Lidocaína/uso terapêutico , Pessoa de Meia-Idade , Perda Auditiva Neurossensorial/tratamento farmacológico , Adulto , Resultado do Tratamento , Perda Auditiva Súbita/tratamento farmacológico , Anestésicos Locais/administração & dosagem , Anestésicos Locais/uso terapêutico , IdosoRESUMO
To address the problems of unstable efficiency, long treatment period, and high energy consumption during microplastics (MPs) removal by traditional coagulation-flotation technology, a gel coagulation-spontaneous flotation (GCSF) process is proposed that employs laminarin (LA) as the crosslinker and polyaluminum chloride (PAC)/polyaluminum ferric chloride (PAFC) as the coagulant to remove MPs. Herein, the effects of GCSF chemical conditions on microplastic-humic acid composite pollutants (MP-HAs) removal were investigated, and the removal mechanisms were analyzed through theoretical calculations and floc structure characterization. Results showed that an LA to PAC/PAFC ratio of 2.5:1 achieved the highest removal of HA (86 %) and MPs (93 %-99 %) in short coagulation (< 1 min) and spontaneous flotation (< 9 min) period. PAC-LA exhibited strong removal ability for MP-HAs while PAFC-LA induced fast flotation speed. The peak intensity and peak shift in Fourier-transformed infrared and X-ray photo-electron spectra indicated that the removal mechanisms of MPs include hydrogen bond adsorption and the sweeping effect, mainly relying on -OH/-C = O on the MPs surface and entrapment of gel flocs with a high degree of aggregation, respectively. The extended Derjaguin-Landau-Verwey-Overbeek calculation also revealed that interactions between PAC/PAFC-LA and MP-HAs were mainly polar interaction (hydrogen bonding) and intermolecular attraction interaction (Lifshitz-van der Waals force), and the sweep effect was reflected by intermolecular interaction. In addition, density function theory calculations indicated that -OH in LA mainly adsorbs DO through a double hydrogen bond configuration, and the crosslinking ligand FeO6/AlO6 assists in DO absorption by -OH.
Assuntos
Microplásticos , Microplásticos/química , Poluentes Químicos da Água/química , Carbono/química , FloculaçãoRESUMO
Lung cancer is a leading cause of cancer-related deaths worldwide. Recent studies have identified pyroptosis, a type of programmed cell death, as a critical process in the development and progression of lung cancer. In this study, we investigated the effect of EEBR, a new compound synthesized by our team, on pyroptosis in non-small cell lung cancer cells (NSCLC) and the underlying molecular mechanisms. Our results demonstrated that EEBR significantly reduced the proliferation and metastasis of NSCLC cells in vitro. Moreover, EEBR-induced pyroptosis in NSCLC cells, as evidenced by cell membrane rupture, the release of cytokines such as interleukin-18 and interleukin-1 beta and the promotion of Gasdermin D cleavage in a Caspase-1-dependent manner. Furthermore, EEBR promoted the nuclear translocation of NF-κB and upregulated the protein level of NLRP3. Subsequent studies revealed that EEBR-induced pyroptosis was suppressed by the inhibition of NF-κB. Finally, EEBR effectively suppressed the growth of lung cancer xenograft tumours by promoting NSCLC pyroptosis in animal models. Taken together, our findings suggest that EEBR induces Caspase-1-dependent pyroptosis through the NF-κB/NLRP3 signalling cascade in NSCLC, highlighting its potential as a candidate drug for NSCLC treatment.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Animais , Humanos , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Piroptose , Caspase 1/metabolismo , Inflamassomos/metabolismoRESUMO
Lysosomal dysfunction can drive carcinogenesis. Lysosomal-associated membrane protein 3 (LAMP3), is a member of the Lysosome Associated Membrane Proteins and is involved in the malignant phenotype such as tumour metastasis and drug resistance, while the mechanisms that regulate the malignant progression of tumour remain vague. Our study aims to provide a more systematic and comprehensive understanding of the role of LAMP3 in the progression of various cancers by various databases.We explored the role of LAMP3 in pan-cancer using The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) database. Multiple online web platforms and software were used for data analysis, including HPA, TIMER, TISIDB, GEPIA, UALCAN, Kaplan-Meier plotter, DAVID and TIGER. The immunohistochemistry was used to quantify the LAMP3 and PD-L1 expression levels in cancer.High LAMP3 expression was found in most cancers and differentially expressed across molecular and immune subtypes. The expression of LAMP3 was involved in the immune-associated processes of Antigen processing and presentation, Th17 cell differentiation, Th1 and Th2 cell differentiation, and the immune-associated pathways of T cell receptor and B cell receptor signalling pathways in most cancers. It also correlated with genetic markers of immunomodulators in various cancers. LAMP3 and PD-L1 expression in BRCA and HNSC tissues was higher than that in corresponding adjacent normal tissues by immunohistochemistry. There is a significant correlation between the expression of LAMP3 and PD-L1.Our study elucidates that LAMP3 has different expression patterns and genetic alteration patterns in different tumours. It is a potential biomarker for immune-related cancer diagnosis, prognosis and efficacy prediction.
Assuntos
Antígeno B7-H1 , Neoplasias , Humanos , Proteína 3 de Membrana Associada ao Lisossomo , Prognóstico , Proteínas de Membrana LisossomalRESUMO
@#[摘 要] 目的:探讨内吞作用相关基因FCHO2在各亚型乳腺癌中的表达及其与乳腺癌患者的预后和免疫细胞浸润的相关性。方法:应用免疫组化法和bc-GenExMiner v5.0数据库数据分析FCHO2在各亚型乳腺癌组织中的表达,通过GEO和TIMER数据库数据分析FCHO2与各亚型乳腺癌患者预后和免疫细胞浸润的关系,利用STRING和GEPIA数据库数据分析与FCHO2的互作蛋白网络和其与互作蛋白的相关性,通过UALCAN和DAVID数据库数据对乳腺癌组织中FCHO2表达相关基因进行KEGG和GO分析。结果:免疫组化法结果显示,FCHO2在管腔型和HER2+乳腺癌组织中均呈高表达(均P<0.05),且与HER2和Ki67表达有关联(P=0.03和P=0.007)。FCHO2高表达的管腔型乳腺癌患者总生存期(OS)和无复发生存期(RFS)均明显缩短(均P<0.05)。FCHO2蛋白与EPS15等多种蛋白表达相关且构成蛋白-蛋白互作网络。KEGG和GO分析显示,乳腺癌组织中FCHO2相关表达基因主要与昼夜节律、自噬等生物学过程有关,涉及叉头框蛋白O(FoxO)和TGF-β等信号通路。FCHO2表达与各亚型乳腺癌组织中的免疫细胞浸润相关(均P<0.05)。结论:FCHO2在管腔型、HER2+乳腺癌组织中呈高表达,且与管腔型乳腺癌患者预后及免疫细胞浸润相关,其可能成为乳腺癌治疗的潜在靶点。
RESUMO
@#[摘 要] 目的:探讨内吞作用相关基因FCHO2在各亚型乳腺癌中的表达及其与乳腺癌患者的预后和免疫细胞浸润的相关性。方法:应用免疫组化法和bc-GenExMiner v5.0数据库数据分析FCHO2在各亚型乳腺癌组织中的表达,通过GEO和TIMER数据库数据分析FCHO2与各亚型乳腺癌患者预后和免疫细胞浸润的关系,利用STRING和GEPIA数据库数据分析与FCHO2的互作蛋白网络和其与互作蛋白的相关性,通过UALCAN和DAVID数据库数据对乳腺癌组织中FCHO2表达相关基因进行KEGG和GO分析。结果:免疫组化法结果显示,FCHO2在管腔型和HER2+乳腺癌组织中均呈高表达(均P<0.05),且与HER2和Ki67表达有关联(P=0.03和P=0.007)。FCHO2高表达的管腔型乳腺癌患者总生存期(OS)和无复发生存期(RFS)均明显缩短(均P<0.05)。FCHO2蛋白与EPS15等多种蛋白表达相关且构成蛋白-蛋白互作网络。KEGG和GO分析显示,乳腺癌组织中FCHO2相关表达基因主要与昼夜节律、自噬等生物学过程有关,涉及叉头框蛋白O(FoxO)和TGF-β等信号通路。FCHO2表达与各亚型乳腺癌组织中的免疫细胞浸润相关(均P<0.05)。结论:FCHO2在管腔型、HER2+乳腺癌组织中呈高表达,且与管腔型乳腺癌患者预后及免疫细胞浸润相关,其可能成为乳腺癌治疗的潜在靶点。
RESUMO
Triple negative breast cancer (TNBC) presents a formidable challenge due to the lack of effective treatment modalities. Immunotherapy stands as a promising therapeutic approach; however, the emergence of drug resistance mechanisms within tumor cells, particularly those targeting apoptosis and pyroptosis, has hampered its clinical efficacy. SHP2 is intricately involved in diverse physiological processes, including immune cell proliferation, infiltration, and tumor progression. Nevertheless, the precise contribution of SHP2 to tumor cell pyroptosis resistance remains inadequately understood. Herein, we demonstrate that SHP2 inhibition hampers the proliferative, migratory, and invasive capabilities of TNBC, accompanied by noticeable alterations in cellular membrane architecture. Mechanistically, we provide evidence that SHP2 depletion triggers the activation of Caspase-1 and GSDMD, resulting in GSDMD-dependent release of LDH, IL-1ß, and IL-18. Furthermore, computational analyses and co-localization investigations substantiate the hypothesis that SHP2 may hinder pyroptosis through direct binding to JNK, thereby impeding JNK phosphorylation. Our cellular experiments further corroborate these findings by demonstrating that JNK inhibition rescues pyroptosis induced by SHP2 knockdown. Strikingly, in vivo experiments validate the suppressive impact of SHP2 knockdown on tumor progression via enhanced JNK phosphorylation. Additionally, SHP2 knockdown augments tumor sensitivity to anti-PD-1 therapy, thus reinforcing the pro-pyroptotic effects and inhibiting tumor growth. In summary, our findings elucidate the mechanism by which SHP2 governs TNBC pyroptosis, underscoring the potential of SHP2 inhibition to suppress cell pyroptosis resistance and its utility as an adjunctive agent for tumor immunotherapy.
Assuntos
Inibidores de Checkpoint Imunológico , Proteína Tirosina Fosfatase não Receptora Tipo 11 , Piroptose , Neoplasias de Mama Triplo Negativas , Humanos , Caspase 1 , Inibidores de Checkpoint Imunológico/uso terapêutico , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Neoplasias de Mama Triplo Negativas/tratamento farmacológicoRESUMO
BACKGROUND: TSTA3 gene encoding GDP-L-fucose synthase has recently been proved to be closely related to the prognosis of patients with various tumors. However, its role in lung cancer is still unclear. The purpose of this study is to explore the expression level, prognostic effect, potential function and mechanism of TSTA3 in lung cancer. METHODS: Based on TCGA database, Kaplan-Meier and COX regression was used to analyze the relationship between TSTA3 expression and prognosis of lung cancer patients. Immunohistochemistry was used to determine the TSTA3 protein expression in lung cancer and normal tissues. The function of TSTA3 in lung squamous cell carcinoma (LUSC) cell was determined by CCK8, colony formation, transwell assay in vitro and subcutaneous xenografts in vivo. Transcriptome analysis, Lyso-Tracker Red staining and rescue experiment were used to explore the possible underlying mechanism. RESULTS: The expression of TSTA3 was significantly increased in lung cancer, especially in LUSC, and was significantly correlated with the malignant characteristics of LUSC. COX regression analysis showed that the high expression of TSTA3 was an independent prognostic factor in LUSC patients. This was also confirmed by immunohistochemical staining. Compared with the control group, the proliferation, colony formation, invasion and migration ability of LUSC cells with TSTA3 overexpression was enhanced. Similarly, the ability of cell proliferation, colony formation, invasion and migration were weakened after transient knockdown of TSTA3. In vivo experiment showed that compared with control group, TSTA3 overexpression significantly promoted the growth of tumor and shortened survival time. In addition, transcriptome sequencing analysis showed that the differentially expressed genes between TSTA3 overexpression and control group was mainly concentrated in the lysosome pathway. Further study found that TSTA3 might affect the proliferation, invasion and migration of LUSC by regulating the expression of lysosome-associated membrane protein 2 (LAMP2) in LUSC. CONCLUSION: The expression level of TSTA3 in LUSC is significantly higher than that in normal tissues. High expression of TSTA3 is associated with poor prognosis of LUSC patients. TSTA3 may affect the proliferation, invasion and migration of LUSC by regulating LAMP2.
RESUMO
Smart window is an attractive option for efficient heat management to minimize energy consumption and improve indoor living comfort owing to their optical properties of adjusting sunlight. To effectively improve the sunlight modulation and heat management capability of smart windows, here, we propose a co-assembly strategy to fabricate the electrochromic and thermochromic smart windows with tunable components and ordered structures for the dynamic regulation of solar radiation. Firstly, to enhance both illumination and cooling efficiency in electrochromic windows, the aspect ratio and mixed type of Au nanorods are tuned to selectively absorb the near-infrared wavelength range of 760 to 1360 nm. Furthermore, when assembled with electrochromic W18O49 nanowires in the colored state, the Au nanorods exhibit a synergistic effect, resulting in a 90% reduction of near-infrared light and a corresponding 5 °C cooling effect under 1-sun irradiation. Secondly, to extend the fixed response temperature value to a wider range of 30-50 °C in thermochromic windows, the doping amount and mixed type of W-VO2 nanowires are carefully regulated. Last but not the least, the ordered assembly structure of the nanowires can greatly reduce the level of haze and enhance visibility in the windows.
RESUMO
ILC3s have been identified as crucial immune regulators that play a role in maintaining host homeostasis and modulating the antitumor response. Emerging evidence supports the idea that LTi cells play an important role in initiating lymphoid tissue development, while other ILC3s can promote host defense and orchestrate adaptive immunity, mainly through the secretion of specific cytokines and crosstalk with other immune cells or tissues. Additionally, dysregulation of ILC3-mediated overexpression of cytokines, changes in subset abundance, and conversion toward other ILC subsets are closely linked with the occurrence of tumors and inflammatory diseases. Regulation of ILC3 cytokines, ILC conversion and LTi-induced TLSs may be a novel strategy for treating tumors and intestinal or extraintestinal inflammatory diseases. Herein, we discuss the development of ILCs, the biology of ILC3s, ILC plasticity, the correlation of ILC3s and adaptive immunity, crosstalk with the intestinal microenvironment, controversial roles of ILC3s in intestinal diseases and potential applications for treatment.
Assuntos
Enteropatias , Neoplasias , Humanos , Linfócitos , Imunidade Inata , Citocinas , Imunoterapia , Microambiente TumoralRESUMO
BACKGROUND: Colorectal cancer (CRC) is the most common type of gastrointestinal tumor, but the available pharmacological treatment is insufficient. As a traditional Chinese medicine, the green walnut husks (QLY) exhibit anti-inflammatory, analgesic, anti-bacterial and anti-tumor effects. However, the effects and molecular mechanisms of QLY extracts on CRC were not yet made known. OBJECTIVE: This study aims to provide efficient and low toxicity drugs for the treatment of CRC. The purpose of this study is to explore the anti-CRC effect and mechanism of QLY, providing preliminary data support for clinical research of QLY. METHODS: Western blotting, Flow cytometry, immunofluorescence, Transwell, MTT, Cell proliferation assay, and xenograft model were used to perform the research. RESULTS: In this study, the potential of QLY to inhibit the proliferation, migration invasion and induce apoptosis of the mouse colorectal cancer cell line CT26 in vitro was identified. The xenograft tumor model of CRC noted that QLY suppressed tumor growth without sacrificing body weight in mice. In addition, QLY-induced apoptosis in tumor cells through NLRC3/PI3K/AKT signaling pathway was revealed. CONCLUSION: QLY regulates the levels of mTOR, Bcl-2 and Bax by affecting the NLRC3/PI3K/AKT pathway to promote apoptosis of tumor cells, suppressing cell proliferation, invasion and migration, and subsequently preventing the progression of colon cancer.
Assuntos
Neoplasias Colorretais , Juglans , Humanos , Animais , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias Colorretais/metabolismo , Apoptose , Proliferação de Células , Linhagem Celular Tumoral , Movimento Celular , Peptídeos e Proteínas de Sinalização Intercelular/uso terapêuticoRESUMO
Using sunlight to produce valuable chemicals and fuels from carbon dioxide (CO2 ), i.e., artificial photosynthesis (AP) is a promising strategy to achieve solar energy storage and a negative carbon cycle. However, selective synthesis of C2 compounds with a high CO2 conversion rate remains challenging for current AP technologies. We performed CO2 photoelectroreduction over a graphene/silicon carbide (SiC) catalyst under simulated solar irradiation with ethanol (C2 H5 OH) selectivity of>99 % and a CO2 conversion rate of up to 17.1â mmol gcat -1 h-1 with sustained performance. Experimental and theoretical investigations indicated an optimal interfacial layer to facilitate the transfer of photogenerated electrons from the SiC substrate to the few-layer graphene overlayer, which also favored an efficient CO2 to C2 H5 OH conversion pathway.
RESUMO
The past decade has witnessed the development of layered-hydroxide-based self-supporting electrodes, but the low active mass ratio impedes its all-around energy-storage applications. Herein, the intrinsic limit of layered hydroxides is broken by engineering F-substituted ß-Ni(OH)2 (Ni-F-OH) plates with a sub-micrometer thickness (over 700 nm), producing a superhigh mass loading of 29.8 mg cm-2 on the carbon substrate. Theoretical calculation and X-ray absorption spectroscopy analysis demonstrate that Ni-F-OH shares the ß-Ni(OH)2 -like structure with slightly tuned lattice parameters. More interestingly, the synergy modulation of NH4 + and F- is found to serve as the key enabler to tailor these sub-micrometer-thickness 2D plates thanks to the modification effects on the (001) plane surface energy and local OH- concentration. Guided by this mechanism, the superstructures of bimetallic hydroxides and their derivatives are further developed, revealing they are a versatile family with great promise. The tailored ultrathick phosphide superstructure achieves a superhigh specific capacity of 7144 mC cm-2 and a superior rate capability (79% at 50 mA cm-2 ). This work highlights a multiscale understanding of how exceptional structure modulation happens in low-dimensional layered materials. The as-built unique methodology and mechanisms will boost the development of advanced materials to better meet future energy demands.
RESUMO
Charge transfer across the electrode-electrolyte interface is a highly complex and convoluted process involving diverse solvated species with varying structures and compositions. Despite recent advances in in situ and operando interfacial analysis, molecular specific reactivity of solvated species is inaccessible due to a lack of precise control over the interfacial constituents and/or an unclear understanding of their spectroscopic fingerprints. However, such molecular-specific understanding is critical to the rational design of energy-efficient solid-electrolyte interphase layers. We have employed ion soft landing, a versatile and highly controlled method, to prepare well-defined interfaces assembled with selected ions, either as solvated species or as bare ions, with distinguishing molecular precision. Equipped with precise control over interfacial composition, we employed in situ multimodal spectroscopic characterization to unravel the molecular specific reactivity of Mg solvated species comprising (i.e., bis(trifluoromethanesulfonyl)imide, TFSI-) anions and solvent molecules (i.e., dimethoxyethane, DME/G1) on a Mg metal surface relevant to multivalent Mg batteries. In situ multimodal spectroscopic characterization revealed higher reactivity of the undercoordinated solvated species [Mg-TFSI-G1]+ compared to the fully coordinated [Mg-TFSI-(G1)2]+ species or even the bare TFSI-. These results were corroborated by the computed reaction pathways and energy barriers for decomposition of the TFSI- within Mg solvated species relative to bare TFSI-. Finally, we evaluated the TFSI reactivity under electrochemical conditions using Mg(TFSI)2-DME-based phase-separated electrolytes representing different solvated constituents. Based on our multimodal study, we report a detailed understanding of TFSI- decomposition processes as part of coordinated solvated species at a Mg-metal anode that will aid the rational design of improved sustainable electrochemical energy technologies.
RESUMO
Atomically dispersed catalysts have been shown highly active for preferential oxidation of carbon monoxide in the presence of excess hydrogen (PROX). However, their stability has been less than ideal. We show here that the introduction of a structural component to minimize diffusion of the active metal center can greatly improve the stability without compromising the activity. Using an Ir dinuclear heterogeneous catalyst (DHC) as a study platform, we identify two types of oxygen species, interfacial and bridge, that work in concert to enable both activity and stability. The work sheds important light on the synergistic effect between the active metal center and the supporting substrate and may find broad applications for the use of atomically dispersed catalysts.
Assuntos
Monóxido de Carbono , Hidrogênio , Monóxido de Carbono/química , Oxirredução , Catálise , Hidrogênio/química , Platina/químicaRESUMO
Rechargeable aqueous zinc-ion batteries (AZIBs) are close complements to lithium-ion batteries for next-generation grid-scale applications owing to their high specific capacity, low cost, and intrinsic safety. Nevertheless, the viable cathode materials (especially manganese oxides) of AZIBs suffer from poor conductivity and inferior structural stability upon cycling, thereby impeding their practical applications. Herein, a facile synthetic strategy of bead-like manganese oxide coated with carbon nanofibers (MnOx-CNFs) based on electrospinning is reported, which can effectively improve the electron/ion diffusion kinetics and provide robust structural stability. These benefits of MnOx-CNFs are evident in the electrochemical performance metrics, with a long cycling durability (i.e., a capacity retention of 90.6% after 2000 cycles and 71% after 5000 cycles) and an excellent rate capability. Furthermore, the simultaneous insertion of H+/Zn2+ and the Mn redox process at the surface and in the bulk of MnOx-CNFs are clarified in detail. Our present study not only provides a simple avenue for synthesizing high-performance Mn-based cathode materials but also offers unique knowledge on understanding the corresponding electrochemical reaction mechanism for AZIBs.
RESUMO
Utilizing reversible lattice oxygen redox (OR) in battery electrodes is an essential strategy to overcome the capacity limitation set by conventional transition metal redox. However, lattice OR reactions are often accompanied with irreversible oxygen oxidation, leading to local structural transformations and voltage/capacity fading. Herein, it is proposed that the reversibility of lattice OR can be remarkably improved through modulating transition metal-oxygen covalency for layered electrode of Na-ion batteries. By developing a novel layered P2-Na0.6 Mg0.15 Mn0.7 Cu0.15 O2 electrode, it is demonstrated that the highly electronegative Cu dopants can improve the lattice OR reversibility to 95% compared to 73% for Cu-free counterpart, as directly quantified through high-efficiency mapping of resonant inelastic X-ray scattering. Crucially, the large energetic overlap between Cu 3d and O 2p states dictates the rigidity of oxygen framework, which effectively mitigates the structural distortion of local oxygen environment upon (de)sodiation and leads to the enhanced lattice OR reversibility. The electrode also exhibits a completely solid-solution reaction with an ultralow volume change of only 0.45% and a reversible metal migration upon cycling, which together ensure the improved electrochemical performance. These results emphasize the critical role of transition metal-oxygen covalency for enhancing the reversibility of lattice OR toward high-capacity electrodes employing OR chemistry.
RESUMO
Sodium-ion batteries (SIBs) have attracted widespread attention for large-scale energy storage, but one major drawback, i.e., the limited capacity of cathode materials, impedes their practical applications. Oxygen redox reactions in layered oxide cathodes are proven to contribute additionally high specific capacity, while such cathodes often suffer from irreversible structural transitions, causing serious capacity fading and voltage decay upon cycling, and the formation process of the oxidized oxygen species remains elusive. Herein, a series of Al-doped P2-type Na0.6 Ni0.3 Mn0.7 O2 cathode materials for SIBs are reported and the corresponding charge compensation mechanisms are investigated qualitatively and quantitatively. The combined analyses reveal that Al doping boosts the reversible oxygen redox reactions through the reductive coupling reactions between orphaned O 2p states in NaOAl local configurations and Ni4+ ions, as directly evidenced by X-ray absorption fine structure results. Additionally, Al doping also induces an increased interlayer spacing and inhibits the unfavorable P2 to O2 phase transition upon desodiation/sodiation, which is common in P2-type Mn-based cathode materials, leading to the great improvement in capacity retention and rate capability. This work provides deeper insights into the development of structurally stable and high-capacity layered cathode materials for SIBs with anion-cation synergetic contributions.