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Covalent organic frameworks (COFs)-based nanoreactors have attracted broad interest in many fields due to their void-confinement effects. However, the inherent drawback of conventional nanoreactors is the lack of internal active sites, which limits their widespread utilization. Herein, we report the construction of hierarchical COF (EB-TFP) nanoreactor with pre-synthesized polyoxometalates (POM, [PV2W10O40]5− (PV2W10)) clusters encapsulated inside of COF (POM@COF). PV2W10@EB-TFP anchors nucleophilic-group (Br− ions) and PV2W10 anion cluster within the COF framework via electrostatic interactions, which not only simplifies the reaction system but also enhances catalytic efficiency. The reaction performance of the PV2W10@EB-TFP nanoreactor can be tuned to achieve excellent catalytic activity in CO2 cycloaddition reaction (CCR) for ∼ 97.63% conversion and ∼ 100% selectivity under visible light irradiation. A mechanistic study based on density functional theory (DFT) calculations and in-situ characterization was also carried out. In summary, we have reported a method for achieving the uniform dispersion of POM single clusters into COF nanoreactor, demonstrating the potential of POM@COF nanoreactor for synergistic photothermal catalytic CO2 cycloaddition. [ABSTRACT FROM AUTHOR]

Nanozyme is a new promising approach to cancer therapy for its ability to induce ferroptosis by activating H2O2 via a traditional radical pathway and enhance cancer immunotherapy. However, short half-life period of hydroxyl radical (·OH) results in unsatisfied effectiveness. Herein, we synthesized a single-atom iron nanozyme (Fe-SAzyme), which can activate H2O2 via a non-radical pathway to generate Fe-based reactive oxygen species (ROS) (O=FeO3=O) for promoting the ferroptosis of pancreatic cancer cells. This Fe-SAzyme could be specifically phagocytosed by pancreatic cancer cells, increasing ROS levels and inhibiting glutathione (GSH) synthesis, which activates ferroptosis. Tumor magnetic resonance imaging (MRI) showed decreased T2 signal after intravenous injection of RGD@Fe-AC (AC = activated carbon). Moreover, RGD@Fe-AC promoted dendritic cell (DC) maturation, overcame Treg-mediated immunosuppression, activated T cells to trigger adaptive immune responses, and enhanced the efficacy of α-PD-L1 immunotherapy. Our research demonstrated that RGD@Fe-AC provided a straightforward, easily implemented, and selective approach for pancreatic cancer treatment and immunotherapy. [ABSTRACT FROM AUTHOR]

Wilms tumor (WT) is the most common malignancy of the genitourinary system in children. Currently, the Integration of single-cell RNA sequencing (scRNA-Seq) and Bulk RNA sequencing (RNA-Seq) analysis of heterogeneity between different cell types in pediatric WT tissues could more accurately find prognostic markers, but this is lacking. RNA-Seq and clinical data related to WT were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. Small nucleolar RNA host gene 15 (SNHG15) was identified as a risk signature from the TARGET dataset by using weighted gene co-expression network analysis, differentially expressed analysis and univariate Cox analysis. After that, the functional mechanisms, immunological and molecular characterization of SNHG15 were investigated at the scRNA-seq, pan-cancer, and RNA-seq levels using Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), ESTIMATE, and CIBERSORT. Based on scRNA-seq data, we identified 20 clusters in WT and annotated 10 cell types. Integration of single-cell and spatial data mapped ligand-receptor networks to specific cell types, revealing M2 macrophages as hubs for intercellular communication. In addition, in vitro cellular experiments showed that siRNAs interfering with SNHG15 significantly inhibited the proliferation and migration of G401 cells and promoted the apoptosis of G401 cells compared with the control group. The effect of siRNAs interfering with SNHG15 on EMT-related protein expression was verified by Western blotting assay. Thus, our findings will improve our current understanding of the pathogenesis of WT, and they are potentially valuable in providing novel prognosis markers for the treatment of WT. [ABSTRACT FROM AUTHOR]

A highly sensitive pressure-sensitive sensor based on MXene was developed using the electrostatic self-assembly method, with carbide sponges as the elastic substrate and a rational design. Specifically, CTAB was used to treat the carbide triamine sponge and conduct the electrostatic self-assembly with MXene to achieve a tightly combined conductive filler and substrate. The resulting pressure sensor showed excellent performance, with a high sensitivity of 15.05 kPa−1 under a range of 0–20 kPa, a response time of 0.1 s, and high durability under 2000 loading–unloading cycles. The minimum detection limit of the sensor was as low as 0.3 Pa, demonstrating excellent monitoring performance. Additionally, finite-element simulation analysis showed that MXene@CTAB@CMF had even better sensing performance at the same stress level. Moreover, the pressure sensor exhibited good sensing performance for various physiological signals and daily work monitoring of the human body, indicating its potential application value. [ABSTRACT FROM AUTHOR]

The corrosive anions (e.g., Cl−) have been recognized as the origins to cause severe corrosion of anode during seawater electrolysis, while in experiments it is found that natural seawater (~0.41 M Cl−) is usually more corrosive than simulated seawater (~0.5 M Cl−). Here we elucidate that besides Cl−, Br− in seawater is even more harmful to Ni-based anodes because of the inferior corrosion resistance and faster corrosion kinetics in bromide than in chloride. Experimental and simulated results reveal that Cl− corrodes locally to form narrow-deep pits while Br− etches extensively to generate shallow-wide pits, which can be attributed to the fast diffusion kinetics of Cl− and the lower reaction energy of Br− in the passivation layer. Additionally, for the Ni-based electrodes with catalysts (e.g., NiFe-LDH) loading on the surface, Br− causes extensive spalling of the catalyst layer, resulting in rapid performance degradation. This work clearly points out that, in addition to anti-Cl− corrosion, designing anti-Br− corrosion anodes is even more crucial for future application of seawater electrolysis. It is known that chloride anions cause severe anode corrosion during seawater electrolysis. Here we found that bromide in seawater is even more harmful to Ni-based anodes, causing the spalling of the catalyst layer and the formation of shallow-wide pits on the substrate, leading to performance degradation. [ABSTRACT FROM AUTHOR]

It is significant to develop highly efficient electrocatalysts for energy conversion systems. Interface engineering is one of the most feasible approaches to effectively enhance the electrocatalytic activity. Herein, the density functional theory (DFT) calculations predict that the potential barriers of Fe sites at the interface of FeP—CoP heterostructures are lower than that of Fe sites in FeP nanoparticles (NPs), Co sites in CoP NPs, or Co sites in heterostructures. Motivated by the DFT calculation results, FeP—CoP heterostructures have been designed and synthesized by a metal—organic frameworks (MOFs) confined-phosphorization method. The FeP—CoP exhibits the lowest overpotential of 230 mV at the current density of 10 mA·cm−2 for oxygen evolution reaction (OER), compared with FeP (470 mV) and CoP (340 mV), which outperforms most of transition metal-based catalysts. The Tafel analysis of FeP—CoP heterostructures shows an improved reaction kinetic pathway with the smallest slope of 90.3 mV·dec−1, as compared to the Tafel slopes of FeP NPs (137 mV·dec−1) and CoP NPs (114 mV·dec−1). And the FeP—CoP shows extraordinary long-term stability over 24 h. The excellent activity and long-term stability of FeP—CoP derive from the synergistic effect between FeP and CoP. [ABSTRACT FROM AUTHOR]

Elucidating the structure-property relationship is crucial for the design of advanced electrocatalysts towards the production of hydrogen peroxide (H2O2). In this work, we theoretically and experimentally discovered that atomically dispersed Lewis acid sites (octahedral M–O species, M = aluminum (Al), gallium (Ga)) regulate the electronic structure of adjacent carbon catalyst sites. Density functional theory calculation predicts that the octahedral M–O with strong Lewis acidity regulates the electronic distribution of the adjacent carbon site and thus optimizes the adsorption and desorption strength of reaction intermediate (*OOH). Experimentally, the optimal catalyst (oxygen-rich carbon with atomically dispersed Al, denoted as O-C(Al)) with the strongest Lewis acidity exhibited excellent onset potential (0.822 and 0.526 V versus reversible hydrogen electrode at 0.1 mA cm−2 H2O2 current in alkaline and neutral media, respectively) and high H2O2 selectivity over a wide voltage range. This study provides a highly efficient and low-cost electrocatalyst for electrochemical H2O2 production.H2O2 production via oxygen reduction offers a renewable approach to obtain an often-used oxidant. Here, authors show the incorporation of Lewis acid sites into carbon-based materials to improve H2O2 electrosynthesis. [ABSTRACT FROM AUTHOR]

Electrochemical synthesis of hydrogen peroxide (H2O2) provides a clean and safe technology for large-scale H2O2 production. The core of this project is the development of highly active and highly selective catalysts. Recent studies demonstrate that carbonaceous materials are favorable catalysts because of their low-cost and tunable surface structures. This brief review first summarizes the strategies of carbonaceous material engineering for selective two-electron O2 reduction reaction and discusses potential mechanisms. In addition, several device designs using carbonaceous materials as catalysts for H2O2 production are introduced. Finally, research directions are proposed for practical application and performance improvement. [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are a class of two-dimensional (2D) layered materials with extensive applications and well-developed synthesizing methods in aqueous media. In this work, we introduce an alcohothermal synthesis method for fabricating NiFe-LDHs with dehydrated galleries. The proposed process involves incomplete hydrolysis of urea for the simultaneous precipitation of metal ions, with the resulting water-deficient ethanol environment leading to the formation of a dehydrated structure. The formation of a gallery-dehydrated layer structure was confirmed by X-ray diffraction (XRD), as well as by a subsequent rehydration process. The methodology introduced here is also applicable for fabricating Fe-based LDHs (NiFe-LDH and NiCoFe-LDH) nanoarrays, which cannot be produced under the same conditions in aqueous media because of the different precipitation processes involved. The LDH nanoarrays exhibit excellent electrocatalytic performance in the oxygen evolution reaction, as a result of their high intrinsic activity and unique structural features. In summary, this study not only introduces a new method for synthesizing LDH materials, but also provides a new route towards highly active and robust electrodes for electrocatalysis. [ABSTRACT FROM AUTHOR]

N-doped porous carbon materials have been prepared by a simple one-step pyrolysis of ethylenediaminetetraacetic acid (EDTA) and melamine in the presence of KOH and Co(NO)·6HO. The combination of the high specific area (1485 m·g), high nitrogen content (10.8%) and suitable graphitic degree results in catalysts exhibiting high activity (with onset and half-wave potentials of 0.88 and 0.79 V vs the reversible hydrogen electrode (RHE), respectively) and four-electron selectivity for the oxygen reduction reaction (ORR) in alkaline medium-comparable to a commercial Pt/C catalyst, but far exceeding Pt/C in stability and durability. Owing to their superb ORR performance, low cost and facile preparation, the catalysts have great potential applications in fuel cells, metal-air batteries, and ORR-related electrochemical industries. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

High specific capacitance per area is a critical requirement for a practical supercapacitor electrode, and needs a combination of high mass-loading of the electrochemically active material per area, and high utilization efficiency of this material. However, pursuing high mass-loading on conventional electrodes usually leads to an increase in 'dead' material which is not accessible to the electrolyte in the supercapacitor, and thus prevents high utilization efficiencies of the material being realized. Here we show that this antagonism can be overcome by incorporating the electrochemically active material in a mesoporous hierarchical architecture. Fabrication of ternary ordered hierarchical CoO@Ni-Co-O nanosheet-nanorod arrays-involving the growth of densely aligned slim Ni-Co-O nanorods (diameter <20 nm) on CoO microsheets which had been previously loaded on macroporous nickel foam-gives a material with excellent electrochemical performance as a supercapacitor electrode. At a current density of 5 mA/cm, the electrodes have both high mass loading per area (12 mg/cm) and high efficiency of 2098 F/g, giving specific capacitances per area as high as ∼25 F/cm. When the current density was increased from 5 to 30 mA/cm, 72% of the specific capacitance was retained and, furthermore, no significant decrease in capacitance was observed over 1000 charge/discharge cycles. The combination of these merits makes the composite material an excellent candidate for practical application as a supercapacitor electrode and, more generally, highlights the increased efficacies of materials which can result from fabricating mesoporous hierarchical structures at the nanoscale. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Previously reported examples of electrochemical pseudocapacitors based on cheap metal oxides have suffered from the need to compromise between specific capacitance, rate capacitance, and reversibility. Here we show that NiO nanorod arrays on Ni foam have a combination of ultrahigh specific capacitance (2018 F/g at 2.27 A/g), high power density (1536 F/g at 22.7 A/g), and good cycling stability (only 8% of capacitance was lost in the first 100 cycles with no further change in the subsequent 400 cycles). This resulted in an improvement in the reversible capacitance record for NiO by 50% or more, reaching 80% of the theoretical value, and demonstrated that a three-dimensional regular porous array structure can afford all of these virtues in a supercapacitor. The excellent performance can be attributed to the slim (< 20 nm) rod morphology, high crystallinity, regularly aligned array structure and strong bonding of the nanorods to the metallic Ni substrate, as revealed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). [InlineMediaObject not available: see fulltext.] [ABSTRACT FROM AUTHOR]