Delicate design of nanostructures for oxygen‐evolution electrocatalysts is an important strategy for accelerating the reaction kinetics of water splitting. In this work, Ni–Fe ...layered‐double‐hydroxide (LDH) nanocages with tunable shells are synthesized via a facile one‐pot self‐templating method. The number of shells can be precisely controlled by regulating the template etching at the interface. Benefiting from the double‐shelled structure with large electroactive surface area and optimized chemical composition, the hierarchical Ni–Fe LDH nanocages exhibit appealing electrocatalytic activity for the oxygen evolution reaction in alkaline electrolyte. Particularly, double‐shelled Ni–Fe LDH nanocages can achieve a current density of 20 mA cm−2 at a low overpotential of 246 mV with excellent stability.
Hierarchical Ni–Fe layered‐double‐hy‐droxide (LDH) nanocages with different shells are designed and synthesized via a one‐pot self‐templating method. Benefiting from the optimized architecture and improved reaction kinetics, the double‐shelled Ni–Fe LDH nanocages demonstrate appealing electrocatalytic activity for the oxygen evolution reaction in an alkaline medium.
Hollow micro‐/nanostructures have attracted tremendous interest owing to their intriguing structure‐induced physicochemical properties and great potential for widespread applications. With the ...development of modern synthetic methodology and analytical instruments, a rapid structural/compositional evolution of hollow structures from simple to complex has occurred in recent decades. Here, an updated overview of research progress made in the synthesis of hollow structures is provided. After an introduction of definition and classification, achievements in synthetic approaches for these delicate hollow architectures are presented in detail. According to formation mechanisms, these strategies can be categorized into four different types, including hard‐templating, soft‐templating, self‐templated, and template‐free methods. In particular, the rationales and emerging innovations in conventional templating syntheses are in focus. The development of burgeoning self‐templating strategies based on controlled etching, outward diffusion, and heterogeneous contraction is also summarized. In addition, a brief overview of template‐free methods and recent advances on combined mechanisms is provided. Notably, the strengths and weaknesses of each category are discussed in detail. In conclusion, a perspective on future trends in the research of hollow micro‐/nanostructures is given.
Hollow nanostructures are of tremendous interest in a wide range of current and emerging fields of science and technology. A roadmap delineating the evolution of these unique structures is discussed, along with a systematic overview of synthetic strategies for hollow structures. Some emergent challenges and perspectives on the future research trends of hollow structures are also provided.
Surface modulation at the atomic level is an important approach for tuning surface chemistry and boosting the catalytic performance. Here, a surface modulation strategy is demonstrated through the ...decoration of isolated Ni atoms onto the basal plane of hierarchical MoS2 nanosheets supported on multichannel carbon nanofibers for boosted hydrogen evolution activity. X‐ray absorption fine structure investigation and density functional theory (DFT) calculation reveal that the MoS2 surface decorated with isolated Ni atoms displays highly strengthened H binding. Benefiting from the unique tubular structure and basal plane modulation, the newly developed MoS2 catalyst exhibits excellent hydrogen evolution activity and stability. This single‐atom modification strategy opens up new avenues for tuning the intrinsic catalytic activity toward electrocatalytic water splitting and other energy‐related processes.
Surface modulation at the atomic level has been an important approach for boosting the performance of electrocatalysts. Here, a combined theoretical and experimental study on Ni atom decorated hierarchical MoS2 nanosheets supported on a multichannel carbon matrix (MCM) is presented. The obtained hybrid MCM@MoS2–Ni electrocatalyst with activated S sites exhibits high performance in electrocatalytic hydrogen evolution.
Hierarchical tubular structures composed of Co3O4 hollow nanoparticles and carbon nanotubes (CNTs) have been synthesized by an efficient multi‐step route. Starting from polymer‐cobalt acetate ...(Co(Ac)2) composite nanofibers, uniform polymer‐Co(Ac)2@zeolitic imidazolate framework‐67 (ZIF‐67) core–shell nanofibers are first synthesized via partial phase transformation with 2‐methylimidazole in ethanol. After the selective dissolution of polymer‐Co(Ac)2 cores, the resulting ZIF‐67 tubular structures can be converted into hierarchical CNTs/Co‐carbon hybrids by annealing in Ar/H2 atmosphere. Finally, the hierarchical CNT/Co3O4 microtubes are obtained by a subsequent thermal treatment in air. Impressively, the as‐prepared nanocomposite delivers a high reversible capacity of 1281 mAh g−1 at 0.1 A g−1 with exceptional rate capability and long cycle life over 200 cycles as an anode material for lithium‐ion batteries.
Forming hierarchies: Hierarchical tubular structures composed of Co3O4 hollow nanoparticles and carbon nanotubes are synthesized from the polymer/cobalt acetate composite nanofibers. Benefiting from unique structural and compositional features, the as‐synthesized hierarchical tubular structures show excellent lithium storage properties.
Hepatocellular carcinoma (HCC) is the third leading cause of worldwide cancer mortality. HCC almost exclusively develops in patients with chronic liver disease, driven by a vicious cycle of liver ...injury, inflammation and regeneration that typically spans decades. Increasing evidence points towards a key role of the bacterial microbiome in promoting the progression of liver disease and the development of HCC. Here, we will review mechanisms by which the gut microbiota promotes hepatocarcinogenesis, focusing on the leaky gut, bacterial dysbiosis, microbe-associated molecular patterns and bacterial metabolites as key pathways that drive cancer-promoting liver inflammation, fibrosis and genotoxicity. On the basis of accumulating evidence from preclinical studies, we propose the intestinal-microbiota-liver axis as a promising target for the simultaneous prevention of chronic liver disease progression and HCC development in patients with advanced liver disease. We will review in detail therapeutic modalities and discuss clinical settings in which targeting the gut-microbiota-liver axis for the prevention of disease progression and HCC development seems promising.
Designing advanced structures for heterojunction photocatalysts is an effective approach to enhance their performance toward solar‐energy conversion. Herein we develop a facile synthetic strategy for ...the fabrication of Fe2O3‐TiO2 microdumbbells. With the assistance of preferentially adsorbed hexadecylamine molecules, amorphous TiO2 nanospheres with tunable size are grown at the two ends of Fe‐based metal–organic compound microrods. Subsequent annealing of the hybrid obtained leads to the formation of a novel heterostructured Fe2O3‐TiO2 microdumbbell photocatalyst. Owing to the heterojunction formed and the unique structure, Fe2O3‐TiO2 microdumbbells with optimized composition and morphology show enhanced performance for photoelectrochemical water oxidation, compared to monophasic Fe2O3 and TiO2 materials as well as physical mixtures thereof.
A weighty performance: A heterostructured Fe2O3‐TiO2 microdumbbell photocatalyst is fabricated through a facile synthetic approach. With their novel heterojunction structure, the well‐defined Fe2O3‐TiO2 microdumbbells exhibit enhanced photoelectrochemical performance compared to Fe2O3 microrods, TiO2 nanospheres, and mixtures of the two.
In situ weaving an all‐carbon graphdiyne coat on a silicon anode is scalably realized under ultralow temperature (25 °C). This economical strategy not only constructs 3D all‐carbon mechanical and ...conductive networks with reasonable voids for the silicon anode at one time but also simultaneously forms a robust interfacial contact among the electrode components. The intractable problems of the disintegrations in the mechanical and conductive networks and the interfacial contact caused by repeated volume variations during cycling are effectively restrained. The as‐prepared electrode demostrates the advantages of silicon regarding capacity (4122 mA h g−1 at 0.2 A g−1) with robust capacity retention (1503 mA h g−1) after 1450 cycles at 2 A g−1, and a commercial‐level areal capacity up to 4.72 mA h cm−2 can be readily approached. Furthermore, this method shows great promises in solving the key problems in other high‐energy‐density anodes.
The growth of all‐carbon graphdiyne under ultralow temperature is applied to construct in situ the 3D mechanical and conductive networks for a Si anode. Such a strategy well demonstrates the advantages of Si in lithium storage (4122 mA h g−1), and greatly improves the long‐term retention (1503 mA h g−1) after 1450 cycles at 2 A g−1.
Monolithic ionogel electrolyte membranes (IGEMs) based on gelling scaffolds and ionic liquids have aroused intensive interest because of their broad processing compatibility, nonflammability, and ...favorable thermal and electrochemical features. However, the absence of functional scaffolds that concurrently enable high mechanical strength and Li+ transportability of IGEMs constrains the battery power and safety. Herein, a task‐specific IGEM monolith featuring high Li+ conductivity and outstanding thermal stability is demonstrated, whereby electrospun positively charged poly(ionic liquid) nanofibers serve as a thermotolerant scaffold for the IGEM. Regulating the Li+ environment in the IGEM enables the shift from the sluggish vehicular to fast structural Li‐ion transport mode. With the unique IGEM, the solid‐state Li||LiFePO4 cells achieve improved rate capability and good cyclability in a wide temperature range from 0 to 90 °C. Furthermore, practical solid‐state Li||LiFePO4 pouch cells with a cathode capacity of ≈2 mAh cm−2 have also been demonstrated.
Regulating the Li+ environment via task‐specific scaffolds enables ionogel electrolytes with fast structural Li+ mobility. An unusual monolithic ionogel electrolyte membrane (IGEM) based on poly(ionic liquid) nanofibers with a high Li‐ion transference number is demonstrated. Practical solid‐state Li|IGEM|LiFePO4 cells achieve outstanding rate capability in a wide temperature range from 0 to 90 °C.
Rational design of complex metal–organic framework (MOF) hybrid precursors offers a great opportunity to construct various functional nanostructures. Here, a novel MOF‐hybrid‐assisted strategy to ...synthesize Co3O4/Co‐Fe oxide double‐shelled nanoboxes is reported. In the first step, zeolitic imidazolate framework‐67 (ZIF‐67, a Co‐based MOF)/Co‐Fe Prussian blue analogue (PBA) yolk–shell nanocubes are formed via a facile anion‐exchange reaction between ZIF‐67 nanocube precursors and Fe(CN)63− ions at room temperature. Subsequently, an annealing treatment is applied to prepare Co3O4/Co‐Fe oxide double‐shelled nanoboxes. Owing to the structural and compositional benefits, the as‐derived Co3O4/Co‐Fe oxide double‐shelled nanoboxes exhibit enhanced electrocatalytic performance for oxygen evolution reaction in alkaline solution.
Yolk–shelled zeolitic imidazolate framework‐67 (ZIF‐67)/Co‐Fe Prussian blue analogue nanocubes are synthesized via an anion‐exchange reaction between ZIF‐67 nanocubes and Fe(CN)63− ions. After thermal treatment in air, the complex metal–organic framework hybrid precursors are transformed into double‐shelled Co3O4/Co‐Fe oxide nanoboxes, which exhibit enhanced performance as an electrocatalyst for the oxygen evolution reaction.
Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles ...in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.
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