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《International Journal of Hydrogen Energy》2022,47(10):6700-6709
Water electrolysis is the most clean and high-efficiency technology for production of hydrogen, an ultimate clean energy in future. Highly efficient non-noble electrocatalysts for hydrogen evolution reaction (HER) are desirable for large scale production of hydrogen by water electrolysis. Especially, exposing as many active sites as possible is a vital way to improve activities of the catalysts. Herein, a series of new hydrangea like composite catalysts of ultrathin Mo2S3 nanosheets assembled uprightly and interlacedly on N, S-dual-doped graphitic biocarbon spheres were facilely prepared. The unique structure endowed the catalysts highly exposed edge active sites and prominently high activities for HER. Especially, the optimized catalyst Mo2S3/NSCS-50 exhibited as low as 106 mV of overpotential at 10 mA/cm2 (denoted as ?10). The catalyst also showed low Tafel slope of 53 mV/dec, low electron transfer resistance of 34 Ω and high stability evidenced by the result that the current density only attenuated 11.7% after 10 h i-t test. The catalyst has shown broad prospect for commercial application in water electrolysis. 相似文献
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《International Journal of Hydrogen Energy》2022,47(26):12829-12840
In the present work, nitrogen doped hierarchically activated porous carbon (APC) samples have been synthesized via single step scalable method using ethylene di-amine tetra acetic acid (EDTA) as precursor and KOH as activating agent. Activated porous carbons with different pore sizes have been developed by varying the activation temperature. SEM, TEM and SAXS analysis suggest that with variation of activation temperature, a hierarchical porous structure with interconnected meso-pore and micro pores has been achieved. The sufficiently high surface area of the synthesized materials provides active sites to enhance the diffusion of ions between the electrolyte and the carbon electrodes. The electrode prepared at 800 °C activated sample exhibited highest specific capacitance of 274 Fg-1 in two electrode setup, at a current density of 0.1 Ag-1 in 1 M aqueous H2SO4. Along with this, it showed maximum energy density of 9.5 Whkg?1 at a power density of 64.5 Wkg-1. The remarkable electrochemical performance reveals that the synthesized nitrogen doped activated carbon electrodes derived from EDTA can be tuned to have optimum pore structure and pore size distribution for better electrochemical performance, so it can be considered as a potential electrode material for applications in electrochemical energy storage. 相似文献
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探讨不同质量浓度雪菊精油对希氏肠球菌(Enterococcus hirae)N47产酪胺的影响机制。利用反转录实时定量聚合酶链式反应分析E. hirae在雪菊精油作用下酪氨酸脱羧途径相关基因的表达情况;利用高效液相色谱法检测不同质量浓度雪菊精油对E. hirae产酪胺的影响。并将E. hirae接入到含不同质量浓度雪菊精油的熏马肠中发酵,评估香肠pH值、菌落总数和酪胺积累量。结果表明:在E. hirae纯培养体系和熏马肠体系中,雪菊精油通过抑制微生物的生长和酪氨酸脱羧途径中tyr DC、tyr P基因的表达,降低酪胺的积累量(P<0.05)。当雪菊精油添加量为1/2最小抑菌浓度(minimal inhibitory concentration,MIC)和MIC时,熏马肠中酪胺的含量分别为78.52 mg/kg和45.83 mg/kg,较对照组分别减少了64.72%和79.41%。 相似文献
27.
海胆酮是一种酮式类胡萝卜素,主要从海胆及藻类等海洋生物中提取。本文研究海胆酮对乙酰胆碱酯酶(acetylcholinesterase,AChE)的抑制作用,应用酶动力学、荧光光谱、圆二色光谱和分子对接技术研究海胆酮对AChE的抑制机理,并用淀粉样β蛋白片段25~35(amyloid beta-peptide 25-35,Aβ25-35)诱导大鼠肾上腺嗜铬细胞瘤细胞(PC12细胞)建立阿尔茨海默症(Alzheimer’s disease,AD)模型,研究海胆酮对AD细胞模型氧化应激损伤的作用。结果表明,海胆酮有很强的AChE抑制活性,其半抑制质量浓度为(16.29±0.97)μg/mL,抑制常数Ki为3.82 μg/mL,表现为竞争性抑制;海胆酮可诱导AChE二级结构改变,更容易与AChE活性中心氨基酸Ser200、His440、Trp84和Tyr121结合,阻碍底物碘代硫代乙酰胆碱(acetylthiocholine iodide,ATCI)与酶结合,从而引起酶活力降低。海胆酮能有效抑制Aβ25-35诱导PC12细胞的AChE活力,降低丙二醛含量,增加超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶活力,减轻Aβ25-35诱导的PC12细胞氧化应激损伤。本研究基于AChE和氧化应激阐明了海胆酮对AD的潜在作用机制,为海胆酮在功能食品、生物医药等领域的应用提供了数据支持和理论根据。 相似文献
28.
The deterministic and probabilistic prediction of ship motion is important for safe navigation and stable real-time operational control of ships at sea. However, the volatility and randomness of ship motion, the non-adaptive nature of single predictors and the poor coverage of quantile regression pose serious challenges to uncertainty prediction, making research in this field limited. In this paper, a multi-predictor integration model based on hybrid data preprocessing, reinforcement learning and improved quantile regression neural network (QRNN) is proposed to explore the deterministic and probabilistic prediction of ship pitch motion. To validate the performance of the proposed multi-predictor integrated prediction model, an experimental study is conducted with three sets of actual ship longitudinal motions during sea trials in the South China Sea. The experimental results indicate that the root mean square errors (RMSEs) of the proposed model of deterministic prediction are 0.0254°, 0.0359°, and 0.0188°, respectively. Taking series #2 as an example, the prediction interval coverage probabilities (PICPs) of the proposed model of probability predictions at 90%, 95%, and 99% confidence levels (CLs) are 0.9400, 0.9800, and 1.0000, respectively. This study signifies that the proposed model can provide trusted deterministic predictions and can effectively quantify the uncertainty of ship pitch motion, which has the potential to provide practical support for ship early warning systems. 相似文献
29.
为明确大豆蛋白纳米纤维的结构形成和扩宽铁强化剂的食品工业应用,以大豆分离蛋白(soy protein isolate,SPI)为原料,通过5 h的酸热处理制备纳米纤维(soy protein isolate fibrils,Fib SPI),系统研究纤维形成前后蛋白结构的变化,并进一步制备铁纳米颗粒(iron nanoparticles,Fe NPs),探究Fib SPI对铁的稳态化作用。研究结果表明:在酸热处理过程中,SPI产生大量的β-折叠结构,其与硫磺素T结合,显示出增强的荧光强度;此外,7S组分先发生降解,利于纤维成核形成,随后11S逐渐被水解,促进纤维生长;同时水解产生大量的小肽组分,提高了产物的还原力。研究进一步利用Fib SPI递送铁纳米颗粒(Fe NPs),发现与原始SPI相比,铁纳米颗粒可在Fib SPI原位形成胶体稳定的铁-大豆蛋白纳米纤维复合物(Fe FibSPI),并以Fe(II)形式存在,其对乳液体系色泽及稳定性的影响较硫酸亚铁或氯化铁小。该研究可为构建新型植物基铁强化剂递送体系提供理论和方法指导。 相似文献
30.
《International Journal of Hydrogen Energy》2022,47(59):24796-24806
Developing inexpensive and efficient electrocatalysts for hydrogen evolution reaction (HER) in both acidic and alkaline mediums is of great significance to the hydrogen energy industry. Hereby, we prepared a mixture of precursors with homogeneous composition by using the chelating ability of soybean protein isolate (C and N source) and phytic acid (dopant and phosphating agent) with cobalt ions, and achieved one-step synthesis and construction of Co2P/N–P co-doped porous carbon composite by carbonization at 800 °C. The as-synthesized Co2P/NPPC-800 electrocatalyst exhibits low HER overpotentials of 121 and 125 mV at 10 mA cm?2 in 0.5 M H2SO4 and 1.0 M KOH, which are close to those of the commercial Pt/C catalyst. Additionally, the NPPC substrate surrounding the Co2P could diminish the corrosion during the HER, and Co2P/NPPC-800 displays good stability and durability. Furthermore, this work offers a convenient synthesis strategy for phosphide/doped porous carbon composites in other electrochemical energy technologies. 相似文献