Design and synthesis of advanced nanomaterials towards electrocatalytic nitrogen reduction and transformation are concluded from both structural and compositional aspects.

and sustainable energy sources, which have been considered as an encouraging solution to significantly reduce the dependency on traditional fossil fuels. Hydrogen is a promising clean energy carrier by virtue of zero-carbon content and the highest gravimetric energy density. [1] In this scenario, hydrogen production through electricity-driven water splitting represents a promising strategy for renewable energy conversion.Water electrolysis involves hydrogen evolution reaction (HER) on cathode and oxygen evolution reaction (OER) on anode. Theoretically, it requires a potential difference of 1.23 V between anode and cathode for driving the overall reaction. [2] But actually, a much higher voltage is needed in a practical water electrolyzer due to the overpotentials on both electrodes. HER is a relatively simple two-electron transport process involving electrochemical H + adsorption and desorption of H 2 . In contrast, OER is an inherently more complex process and has sluggish oxygen evolution kinetics, since it needs to transfer four electrons through multi-step reactions with single-electron transfer at each step. [3] As a result, the accumulation of energy at each step makes OER kinetically hindered and a large overpotential is needed to overcome the kinetic energy barrier. On the other hand, OER is an important half reaction involved in rechargeable metal-air batteries which are also regarded as the emerging sustainable energy conversion technology. Nevertheless, the bottlenecks such as low lifetimes, inferior energy conversion efficiency, and limited stability of metal-air batteries mainly originate from the intrinsically sluggish kinetics of OER. [4] Hence, developing effective and stable OER electrocatalysts by improving oxygen electrokinetics can significantly contribute to improving energy-conversion efficiency.To date, transition metal-based OER catalysts have been extensively studied by virtue of their excellent OER catalytic activities. [5] Noble-metal-based electrocatalysts have been considered as the most powerful electrocatalysts for OER in spite of their high prices. Among them, Ru and Ir have been verified to outperform Pt, Pd, and Rh. [6] Considering the high potential applied during OER, noble-metal oxides such as IrO 2 and RuO 2 are widely chosen as the state-of-the-art electrocatalysts. Nevertheless, RuO 2 is highly unstable in both acidic and alkaline electrolytes under high anodic potential. [7] Although IrO 2 Oxygen evolution reaction (OER) is an important half-reaction involved in many electrochemical applications, such as water splitting and rechargeable metal-air batteries. However, the sluggish kinetics of its four-electron transfer process becomes a bottleneck to the performance enhancement. Thus, rational design of electrocatalysts for OER based on thorough understanding of mechanisms and structure-activity relationship is of vital significance. This review begins with the introduction of OER mechanisms which include conventional adsorbate evolution mechanism and lattice-oxygen-mediated...

Ferroptosis is a regulated form of cell death driven by small molecules or conditions that induce lipid-based reactive oxygen species (ROS) accumulation. This form of iron-dependent cell death is morphologically and genetically distinct from apoptosis, necroptosis, and autophagy. miRNAs are known to play crucial roles in diverse fundamental biological processes. However, to date no study has reported miRNA-mediated regulation of ferroptosis. Here we show that miR-137 negatively regulates ferroptosis by directly targeting glutamine transporter SLC1A5 in melanoma cells. Ectopic expression of miR-137 suppressed SLC1A5, resulting in decreased glutamine uptake and malondialdehyde (MDA) accumulation. Meanwhile, antagomir-mediated inactivation of endogenous miR-137 increased the sensitivity of melanoma cells to erastin- and RSL3-induced ferroptosis. Importantly, knockdown of miR-137 increased the antitumor activity of erastin by enhancing ferroptosis both in vitro and in vivo. Collectively, these data indicate that miR-137 plays a novel and indispensable role in ferroptosis by inhibiting glutaminolysis and suggest a potential therapeutic approach for melanoma.

Heterogeneous catalysts of inexpensive and reusable transition-metal are attractive alternatives to homogeneous catalysts; the relatively low activity of transition-metal nanoparticles has become the main hurdle for their practical applications. Here, the de novo design of a Mott–Schottky-type heterogeneous catalyst is reported to boost the activity of a transition-metal nanocatalyst through electron transfer at the metal/nitrogen-doped carbon interface. The Mott–Schottky catalyst of nitrogen-rich carbon-coated cobalt nanoparticles (Co@NC) was prepared through direct polycondensation of simple organic molecules and inorganic metal salts in the presence of g-C3N4 powder. The Co@NC with controllable nitrogen content and thus tunable Fermi energy and catalytic activity exhibited a high turnover frequency (TOF) value (8.12 mol methyl benzoate mol–1 Co h–1) for the direct, base-free, aerobic oxidation of benzyl alcohols to methyl benzoate; this TOF is 30-fold higher than those of the state-of-the-art transition-metal-based nanocatalysts reported in the literature. The presented efficient Mott–Schottky catalyst can trigger the synthesis of a series of alkyl esters and even diesters in high yields.

Ferroptosis is a newly defined form of regulated cell death characterized by the irondependent accumulation of lipid hydroperoxides. Erastin, the ferroptosis activator, binds to voltage-dependent anion channels VDAC2 and VDCA3, but treatment with erastin can result in the degradation of the channels. Here, the authors show that Nedd4 is induced following erastin treatment, which leads to the ubiquitination and subsequent degradation of the channels. Depletion of Nedd4 limits the protein degradation of VDAC2/3, which increases the sensitivity of cancer cells to erastin. By understanding the molecular mechanism of erastin-induced cellular resistance, we can discover how cells adapt to new molecules to maintain homeostasis. Furthermore, erastin-induced resistance mediated by FOXM1-Nedd4-VDAC2/3 negative feedback loop provides an initial framework for creating avenues to overcome the drug resistance of ferroptosis activators.