Bifunctional Nitrogen-Doped Microporous Carbon Microspheres Derived from Poly(<i>o</i>‑methylaniline) for Oxygen Reduction and Supercapacitors

Heteroatom-doped carbon materials have attracted significant attention because of their applications in oxygen reduction reaction (ORR) and supercapacitors. Here we demonstrate a facile poly­(<i>o</i>-methylaniline)-derived fabrication of bifunctional microporous nitrogen-doped carbon microspheres (NCMSs) with high electrocatalytic activity and stability for ORR and energy storage in supercapacitors. At a pyrolysis temperature of 900 °C, the highly dispersed NCMSs present a high surface area (727.1 m² g^–1), proper total content of doping N, and high concentration of quaternary N, which exhibit superior electrocatalytic activities for ORR to the commercial Pt/C catalysts, high specific capacitance (414 F g^–1), and excellent durability, making them very promising for advanced energy conversion and storage. The presented conducting polymer-derived strategy may provide a new way for the fabrication of heteroatom-doped carbon materials for energy device applications

Oxidative stress tolerance analysis of <i>TaPP2C1</i>-overexpressing plants.

<p>Photos of WT and transgenic lines after MV (A) and H₂O₂ (B) treatments. The H₂O₂ content and the activities of SOD and CAT in the WT and transgenic lines under normal condition and MV treatment (C). The expression of <i>NtSOD</i> and <i>NtCAT</i> in the WT and transgenic lines under normal condition and MV treatment (D). Data are means ±SD of n = 4 independent experiments. Asterisks indicate significant difference between WT and transgenic lines (*<i>P</i> <0.05; **<i>P</i> <0.01).</p

Salt stress tolerance analysis of <i>TaPP2C1</i>-overexpressing tobacco plants during seeds germination and root elongation.

<p>Seedling phenotypes (A, B) and germination rates (a, b) of WT and transgenic lines under standard condition (A, a) or 200 mM NaCl (B, b) treatment. A and B are photos of the 8 d after germination on media. Seedling phenotypes (C, D, E) and root length (F) of WT and transgenic lines under standard condition (C), 100 mM NaCl (D) or 200 mM NaCl (E) treatment. Data are means ±SD of n = 4 independent experiments. Means denoted by the same letter do not significantly differ at <i>P</i> <0.05 as determined by Duncan’s multiple range test.</p

ABA sensitivity of <i>TaPP2C1</i>-overexpressing tobacco plants.

<p>Seedling phenotypes (A, B, C) and germination rates (a, b, c) of WT and transgenic lines under standard condition (A, a), 0.5 μM ABA (B, b), or 1 μM ABA (C, c) treatment. A, B and C are photos of the 12 d after germination on media. Seedling phenotypes (D, E, F) and root length (G) of WT and transgenic lines under standard condition (D), 0.5 μM ABA (E) or 1 μM ABA (F) treatment. Relative expression levels of ABA associated genes in transgenic line (OE 8) and WT under normal condition or 1μM ABA treatment (H). The mRNA fold difference was relative to that of WT samples under normal condition. Data are means ±SD of n = 4 independent experiments. Means denoted by the same letter do not significantly differ at <i>P</i> <0.05 as determined by Duncan’s multiple range test.</p

Physiological analysis of WT and transgenic lines under normal and saline condition.

<p>Analysis of IL (A), MDA (B) and H₂O₂ (C), and the activities of SOD (E) and CAT (F) in the WT and transgenic lines under normal condition and salt treatment. Histochemical detection of H₂O₂ accumulation of 7 d old tobacco plants subjected to 7 d 200 mM NaCl stress (D). Data are means ±SD of n = 4 independent experiments. Asterisks indicate significant difference between WT and transgenic lines (*<i>P</i> <0.05; **<i>P</i> <0.01).</p

<i>TaPP2C1</i>, a Group F2 Protein Phosphatase 2C Gene, Confers Resistance to Salt Stress in Transgenic Tobacco

<div><p>Group A protein phosphatases 2Cs (PP2Cs) are essential components of abscisic acid (ABA) signaling in Arabidopsis; however, the function of group F2 subfamily PP2Cs is currently less known. In this study, TaPP2C1 which belongs to group F2 was isolated and characterized from wheat. Expression of the TaPP2C1-GFP fusion protein suggested its ubiquitous localization within a cell. <i>TaPP2C1</i> expression was downregulated by abscisic acid (ABA) and NaCl treatments, but upregulated by H₂O₂ treatment. Overexpression of <i>TaPP2C1 </i>in tobacco resulted in reduced ABA sensitivity and increased salt resistance of transgenic seedlings. Additionally, physiological analyses showed that improved resistance to salt stress conferred by <i>TaPP2C1 </i>is due to the reduced reactive oxygen species (ROS) accumulation, the improved antioxidant system, and the increased transcription of genes in the ABA-independent pathway. Finally, transgenic tobacco showed increased resistance to oxidative stress by maintaining a more effective antioxidant system. Taken together, these results demonstrated that TaPP2C1 negatively regulates ABA signaling, but positively regulates salt resistance. TaPP2C1 confers salt resistance through activating the antioxidant system and ABA-independent gene transcription process.</p></div

Subcellular localization of TaPP2C1 protein.

<p>(A) 35S::TaPP2C1-GFP and 35 S::GFP (positive control) constructs were transiently expressed in onion epidermal cells and observed with a microscopy after 48 h of bombardment. (B) 35S::TaPP2C1-GFP were transiently expressed in tobacco leaf cells. Two independent experiments produced similar results.</p

Ultrasmall MnO Nanoparticles Supported on Nitrogen-Doped Carbon Nanotubes as Efficient Anode Materials for Sodium Ion Batteries

Sodium ion batteries (SIBs) have attracted increasing attentions as promising alternatives to lithium ion batteries (LIBs). Herein, we design and synthesize ultrasmall MnO nanoparticles (∼4 nm) supported on nitrogen-doped carbon nanotubes (NDCT@MnO) as promising anode materials of SIBs. It is revealed that the carbonization temperature can greatly influence the structural features and thus the Na-storage behavior of the NDCT@MnO nanocomposites. The synergetic interaction between MnO and NDCT in the NDCT@MnO nanocomposites provides high rate capability and long-term cycling life due to high surface area, electrical conductivity, enhanced diffusion rate of Na⁺ ions, and prevented agglomeration and high stability of MnO nanoparticles. The resulting SIBs provide a high reversible specific capacity of 709 mAh g^–1 at a current density of 0.1 A g^–1 and a high capacity of 536 mAh g^–1 almost without loss after 250 cycles at 0.2 A g^–1. Even at a high current density of 5 A g^–1, a capacity of 273 mAh g^–1 can be maintained after 3000 cycles

Fe and Cu Double-Doped Co₃O₄ Nanorod with Abundant Oxygen Vacancies: A High-Rate Electrocatalyst for Tandem Electroreduction of Nitrate to Ammonia

The electrochemical nitrate reduction reaction (NO3RR) is an attractive green alternative to the conventional Haber–Bosch method for the synthesis of NH3. However, this reaction is a tandem process that involves multiple steps of electrons and protons, posing a significant challenge to the efficient synthesis of NH3. Herein, we report a high-rate NO3RR electrocatalyst of Fe and Cu double-doped Co3O4 nanorod (Fe1/Cu2-Co3O4) with abundant oxygen vacancies, where the Cu preferentially catalyzes the rapid conversion of NO3– to NO2– and the oxygen vacancy in the Co3O4 substrate can accelerate NO2– reduction to NH3. In addition, the introduction of Fe can efficiently capture atomic H* that promotes the dynamics of NO2– to NH3, improving Faradaic efficiency of the produced NH3. Controlled experimental results show that the optimal electrocatalyst of Fe1/Cu2-Co3O4 exhibits good performance with high conversion (93.39%), Faradaic efficiency (98.15%), and ammonia selectivity (98.19%), which is significantly better than other Co-based materials. This work provides guidance for the rational design of high-performance NO3RR catalysts

Overexpression of the Wheat Aquaporin Gene, <em>TaAQP7</em>, Enhances Drought Tolerance in Transgenic Tobacco

<div><p>Aquaporin (AQP) proteins have been shown to transport water and other small molecules through biological membranes, which is crucial for plants to combat stress caused by drought. However, the precise role of <em>AQPs</em> in drought stress response is not completely understood in plants. In this study, a <em>PIP2</em> subgroup gene <em>AQP</em>, designated as <em>TaAQP7</em>, was cloned and characterized from wheat. Expression of TaAQP7-GFP fusion protein revealed its localization in the plasma membrane. TaAQP7 exhibited high water channel activity in <em>Xenopus laevis</em> oocytes and <em>TaAQP7</em> transcript was induced by dehydration, and treatments with polyethylene glycol (PEG), abscisic acid (ABA) and H₂O₂. Further, <em>TaAQP7</em> was upregulated after PEG treatment and was blocked by inhibitors of ABA biosynthesis, implying that ABA signaling was involved in the upregulation of <em>TaAQP7</em> after PEG treatment. Overexpression of <em>TaAQP7</em> increased drought tolerance in tobacco. The transgenic tobacco lines had lower levels of malondialdehyde (MDA) and H₂O₂, and less ion leakage (IL), but higher relative water content (RWC) and superoxide dismutase (SOD) and catalase (CAT) activities when compared with the wild type (WT) under drought stress. Taken together, our results show that <em>TaAQP7</em> confers drought stress tolerance in transgenic tobacco by increasing the ability to retain water, reduce ROS accumulation and membrane damage, and enhance the activities of antioxidants.</p> </div