Ni/Ni₃C Core/Shell Hierarchical Nanospheres with Enhanced Electrocatalytic Activity for Water Oxidation

Developing efficient and low-cost catalysts with high activity and excellent electrochemical and structural stability toward the oxygen evolution reaction (OER) is of great significance for both energy and environment sustainability. Herein, Ni/Ni₃C core/shell hierarchical nanospheres have been in situ synthesized via an ionic liquid-assisted hydrothermal method at relatively low temperature. Ionic liquid 1-butyl-3-methylimidazolium acetate has played multiple roles in the whole synthesis process. Benefiting from the high electrical conductivity, more exposed active sites and the core/shell interface effect, the obtained Ni/Ni₃C core/shell hierarchical nanospheres exhibit an outstanding OER performance with lower overpotential, small Tafel slope, and excellent stability. This fundamental method and insights with in situ coupling high conductivity metal support and metal carbide in a core/shell nanoarchitecture by an ionic liquid-assisted hydrothermal method would open up a new pathway to achieve high-performance electrocatalysts toward the OER

table1_Homocysteine Impairs Endothelial Cell Barrier Function and Angiogenic Potential via the Progranulin/EphA2 Pathway.docx

Hyperhomocysteinemia is a well-recognized independent risk factor for cardiovascular disease. To date, the mechanism of pathological plasma homocysteine (Hcy) level elevation remains to be elucidated. We aimed to investigate the levels of progranulin (PGRN), Eph-receptor tyrosine kinase-type A2 (EphA2), vascular cell adhesion molecule-1 (VCAM-1), and Hcy in patients with arteriosclerosis and investigate their functions in Hcy-injured human umbilical vein endothelial cells (HUVECs). EphA2 knockdown was induced in HUVECs by shRNA lentivirus infection with EphA2-RNAi, and bulk RNA-seq assay was performed. Then we investigated the mechanism underlying the effect of recombinant human PGRN (rhPGRN) combined with shRNA interference of EphA2 on cell proliferation, migration, and angiogenesis in Hcy-injured HUVECs. Results showed that serum EphA2, VCAM-1, and Hcy levels in acute coronary syndrome patients were significantly higher than those in chronic coronary syndrome patients (p = 0.000; p = 0.000; p = 0.033, respectively). In vitro, we demonstrated that knockdown of EphA2 significantly impaired cell adhesion and inhibited HUVECs migration and angiogenesis (p < 0.001), which was associated with reduction in VCAM1 and VE-cadherin (p < 0.05). Hcy modulated the expression of PGRN and EphA2 in a time-and dose-dependent manner. However, rhPGRN ameliorated the Hcy-induced reduction in cell viability and migration (p < 0.05). Mechanistically, we found that PGRN/EphA2 and its downstream AKT/NF-κB signaling might be the primary signal transduction pathways underlying Hcy-induced injury. The present study illustrated that PGRN plays a previously unrecognized role in Hcy-induced endothelial injury, which is achieved through its interaction with EphA2 signaling, implying a promising therapeutic target for cardiovascular disease.</p

Novel Synthesis Strategy of γ‑AlOOH Nanotubes: Coupling Reaction via Ionic Liquid-Assisted Hydrothermal Route

A novel synthetic strategy, i.e., transition metal ions used to drive a coupling reaction in terms of complex formation of the metal ions and decomposition of a precursor, combined with ionic liquid-assisted hydrothermal route, was utilized to synthesize γ-AlOOH nanotubes with high purity and uniform dimension at a mild condition. These γ-AlOOH nanotubes can be easily transformed to γ-Al₂O₃ nanotubes by calcining at 600 °C for 2 h, without changing the morphology. More specifically, this strategy may be helpful to develop a new opportunity for synthesis of inorganic nanomaterials with novel morphologies and improved properties

General One-Pot Template-Free Hydrothermal Method to Metal Oxide Hollow Spheres and Their Photocatalytic Activities and Lithium Storage Properties

A general and facile one-pot template-free hydrothermal strategy has been developed to synthesize various metal oxide (TiO2, SnO2 and α-Fe2O3) hollow spheres with unified morphologies. The formation of hollow structure involves a trifluoroacetic acid (TFA)-assisted Ostwald ripening process. Photocatalytic activities of the as-prepared TiO2 product are evaluated by the photodegradation of Rhodamine B (RhB), which the TiO2 hollow spheres obtained from 450 °C thermal treatment exhibit higher photocatalytic activity than Degussa P25. In addition, electrochemical measurements demonstrate that all of the as-prepared metal oxides hollow spheres have the potential applications in lithium-ion battery. We have a great expectation that this synthesis strategy can afford a new universal route for functional metal oxide hollow materials preparation without using template

Interface Engineering of Oxygen Vacancy-Enriched Ru/RuO₂–Co₃O₄ Heterojunction for Efficient Oxygen Evolution Reaction in Acidic Media

RuO2 is currently regarded as a benchmark electrocatalyst for water oxidation in acidic media. However, its wide application is still restricted by limited durability and high cost. Herein, we report a Ru/RuO2–Co3O4 catalyst for boosting the acidic oxygen evolution reaction catalytic performance via constructing a heterointerface between RuO2 and Co3O4 and vacancy engineering. The resulting Ru/RuO2–Co3O4 shows a 226 mV overpotential at 10 mA cm–2 and excellent stability with a small overpotential increase after continuous testing for 19 h, greatly surpassing that of commercial RuO2 in a 0.1 M HClO4 solution. Depth structure characterizations involved in XPS, XANES, and EXAFS indicate that the favorable catalytic performance of Ru/RuO2–Co3O4 is mainly ascribed to the interfacial charge transfer by heterojunction interfaces between Co species and Ru species. Co3O4 is adjacent to RuO2 and donates electrons, making the valence state of Ru lowered and the Ru–O covalency weakened, which greatly suppress the dissolution of Ru and thus enhance stability. Meanwhile, the existing oxygen vacancies improve the intrinsic catalytic activity. This study is highly expected to favor the design and synthesis of more highly efficient electrocatalysts applied in energy-related devices

Nd₆Ir₂O₁₃ as an Efficient Electrocatalyst Boosts the Oxygen Evolution Reaction in Acidic Media

A highly active and robust electrocatalyst for the oxygen evolution reaction (OER) in acidic conditions is essential for proton-exchange membrane water electrolyzers. Herein, a novel Nd6Ir2O13 electrocatalyst was synthesized and first applied in acidic OER. During the OER, surface Nd atoms are leached out to form active hydrated IrOx; meanwhile, the coordination environment of Ir remains relatively stable. Benefiting from the low Ir content (26.4 wt %), Nd6Ir2O13 affords an Ir mass activity of 123.5 mA per mgIr at an overpotential of 300 mV, about 42-fold that of IrO2. Notably, Nd6Ir2O13 needs an ultralow overpotential of 291 mV to acquire a current density of 10 mA cm–2 and continuously catalyzes OER for 70,000 s with little overpotential increase, far beyond that of the benchmark IrO2 and most of the electrocatalysts for the acidic OER. This work opens a new type of Ir-based oxides with ultralow Ir content, which expands the acidic OER electrocatalyst family of multimetal oxides

Nuclear translocation of GAPDH and Mst1 during cardiomyocyte apoptosis.

<p>A, NRVMs were treated with chelerythrine (5 µM) for different time points as indicated. Cytoplasmic and nuclear fractions were isolated and then subjected to western blot analysis using ant-GAPDH and anti-histone H1A antibodies. The distribution of GAPDH in the cytoplasmic and nuclear fractions was analyzed by densitometric analysis. Values are means ± SEM obtained from 4 experiments. B, Unstimulated NRVMs or NRVMs stimulated with chelerythrine (5 µM) for 2 hours were fixed and stained with anti-GAPDH monoclonal antibody and rabbit polyclonal anti-Mst1 antibody and processed for confocal imaging. The merged images show clear colocalization of these 2 proteins in cytoplasm in ustimulated cells and translocation and colocalization of these 2 proteins in nucleus in response to chelerythrine. C, NRVMs were transduced with either Ad-LacZ or Ad-Mst1 or Ad-DNMST (MOI = 30). 48 hr after transduction, cells were treated with chelerythrine (5 µM) for 1 hour. Cytoplasmic and nuclear fractions were isolated and then subjected to western blot analysis using anti-GAPDH and anti--tubulin antibodies. D, Unstimulated NRVMs or NRVMs stimulated with chelerythrine (5 µM) for 2 hours were lysed and then subjected to immunoprecipitation with either normal IgG or anti-Mst1 antibody. Immunocomplexes were then separated by 15% SDS-PAGE and transferred membrane was immunoblotted with either anti-GAPDH or Mst1 antibody.</p

Synergistic Effect of Electronic Particle–Support Interactions on the Ir-Based Multiheterostructure for Acidic Water Oxidation

Exploiting durable electrocatalysts with high specific activity for acidic water oxidation is a great challenge due to the high energy barrier for the multiple oxygen evolution reaction (OER) intermediates. Deliberately taking advantage of the synergistic effect of electronic particle–support interactions on both the particle and support may address this concern. Here, we deliberately design a multiheterostructure with an IrO2 shell-coated Ir core anchored on the Co3O4 framework as an efficient acidic OER electrocatalyst. Detailed characterizations (depth-resolved XPS, XANES, and EXAFS) of the electrocatalysts demonstrate that the electronic particle–support interactions lead to a unique electron transfer at the interface from IrO2 and Co3O4 to Ir. Such an electron transfer will result in compressed Ir–O bonds and Co–O bonds, thus simultaneously reducing free energies for OER intermediates on the surfaces of both IrO2 and Co3O4, sufficiently stimulating the synergistic effect to enhance OER activity and stability