Study on the gaseous and electrochemical hydrogen storage properties of as-milled CeMgNi-based alloys

For gaining further insight into the involvement of the gaseous and electrochemical hydrogen storage properties of CeMg₁₂-type alloys, partial substitution and ball milling were both used to synthesize the nanocrystalline and amorphous CeMg₁₁Ni + x wt.% Ni (x = 100, 200) samples. This research aims at elucidating the functional roles of Ni content and milling time on samples' structure and hydrogen storage performance. X-Ray diffraction and high-resolution transmission electron microscope were used to reveal the micro constructions of alloys. To determine the gaseous hydrogen storage property, Sievert's apparatus and a thermal gravity analysis bonded with a H₂ probe were adopted. The dehydrogenation activation energy was computed in the Kissinger method. The electrochemical performances of the as-milled samples were measured through a constant current system. Further researches showed that the electrochemical performance of as-milled samples had been dramatically improved by increasing Ni content. With milling duration lengthens, the gaseous hydrogen absorption capacity, gaseous hydriding rate and high rate discharge capability of samples reached the maximal values, but electrochemical discharge capacity and gaseous dehydriding rate always increased. The dehydrogenation activation energy decrease resulted by improving Ni percent and milling duration was deemed as the cause of the excellent gaseous kinetics of samples.     

A gaseous compound of hydrogen and carbon production performance model in coalbed reservoir with horizontal fractures

Hydrogen energy can be generated by steam methane reforming method, and methane production from coal seams is important to ensure the abundance of hydrogen energy generation. The gaseous compound of hydrogen and carbon production performance analysis is important and pressure transient analysis can be used to analyze the flow characteristics in the development of gaseous compound of hydrogen and carbon in coalbed reservoir. The computational models on vertical wells, vertically fractured wells and horizontal wells have been studied intensively in coalbed reservoir to predict gaseous compound of hydrogen and carbon production behavior. For a thin coalbed methane reservoir, it will be more effective to develop through forming horizontal fractures near the wellbore. However, such model has not been established. To analyze gaseous compound of hydrogen and carbon production performance for horizontal fractures in coalbed methane reservoirs, this paper presents a 3D point-sink model and the corresponding solution is obtained through using Laplace transform and Fourier transform methods. The point-source integral method is used to obtain the general solutions of gaseous compound of hydrogen and carbon flow through horizontal fractures. The pressure transient solution have been compared with numerical simulation to validate its accuracy. Type curves are established to analyze the flow characteristics of gaseous compound of hydrogen and carbon, which can be divided into four regions, i.e., linear flow region, transition flow region, inter-porosity flow region, and radial flow region. The sensitive analysis of the key model parameters on type curves has been conducted.     

Experimental study of effect of hydrogen addition on combustion of low caloric value gas fuels

The effect of hydrogen on the premixed combustion of low calorific value gas in cylinder was carried out. The engine bench test system was built, and the effects of hydrogen on the pressure in cylinder, the characterization parameters of flame stability, flame shape, combustion cycle variation, flame surface structure and development were studied. The experimental results show that adding hydrogen to low calorific value gas fuels can increase laminar flame propagation rate, increase heat release rate, improve engine volumetric efficiency and reduce engine cycle variation. With the increase of hydrogen fraction, the maximum cylinder pressure of the engine rises, the corresponding crankshaft angle moves forward, and the flame development period and the rapid combustion period of the engine working cycle are reduced. The flame propagation rate of hydrogen blended low calorific value gas is larger, which enhances the strength of the vortex blob in cylinder to some extent. The increase of hydrogen fraction in mixture increases the flame propagation velocity, and enhances the effect of the combustion process on vortex intensity in cylinder, which increasing the effect of vortex blob on the flame surface structure. With the increase of hydrogen fraction, the vortices of the flow field in the cylinder increase, the time of which the flame surface reaches the same fold is in advance, and the flame development period is shortened.     

Hydrogen diffusion and the effect of hydrogen on structural transformations in binary TiNi based alloys

The paper analyzes the effect of electrolytic hydrogenation on martensite transformation temperatures in binary TiNi alloys. The analysis shows that this effect can be strong or weak depending on the phase state of TiNi. Research data are presented on the diffusivity of hydrogen in binary TiNi alloys in martensite and austenite states. The diffusion coefficient of hydrogen is estimated from its distribution measured by glow discharge spectroscopy in TiNi after hydrogenation. The experimental results about the formation of TiNiH hydride in the martensitic and austenitic state in binary TiNi based alloys are also presented.     

Alumina supported nano-platinum on copper nanoparticles prepared via galvanic displacement reaction for preferential carbon monoxide oxidation in presence of hydrogen

Improved catalytic centres with a minimum mass-loading of expensive platinum (Pt) have been anticipated for various catalytic applications, for instance preferential oxidation (PROX) of carbon monoxide (CO) in the presence of Hydrogen. Here, we report the synthesis of nano-Pt on the surface of copper (Cu) nanoparticles (NPs) supported on γ-Al₂O₃ (Pt_n(Cu)/γ-Al₂O₃) via galvanic displacement reaction (GDR) for the catalytic CO-PROX reaction. Pt_n(Cu)/γ-Al₂O₃ showed much improved CO-PROX performance compared to that of the as-synthesized Pt_l(Cu)/γ-Al₂O₃ catalyst. Importantly, no significant conversion of hydrogen at a lower temperature range (<200 °C) is observed during the CO-PROX reaction which is one of the essential prerequisites for the CO-PROX reaction. Moreover, Pt_n(Cu)/γ-Al₂O₃ showed the durable, long-term catalytic CO-PROX performance for 120 h. These results infer that realization of nano-Pt on the surface of the Cu NPs holds the promise as the catalytic centres with the minimum mass-loading of Pt for the CO-PROX reaction.     

Graphene oxide guiding the constructing of nickel-iron layered double hydroxides arrays as a desirable bifunctional electrocatalyst for HER and OER

It is accepted that the electrocatalytic activity is correlated to the morphology. Here, graphene oxide guiding nickel and iron layered double hydroxides hybrid arrays (GO-FeNi-LDH) are firstly fabricated by one-step electro-deposition method. The pretty 3D arrays with sheets vertically growing on nickel foam (NF) are highlighted by controlling the quantity of GO. Furthermore, the electron transfer from Ni, Fe to graphene is detected, making the metals and graphene in high valence and electron-rich state, respectively. The optimal GO-FeNi-LDH presents pretty morphology, defects, electron interactions and good conductivity. Therefore, to achieve 10 and 100 mA cm⁻², it requires the overpotentials of 119, 210, 285 and 303 mV for HER and OER and excellent durability. Noticeably, the optimal GO-NiFe-LDH needs a cell voltage of 1.48 V to drive 10 mA cm⁻² for the whole water splitting, which are lower than that of most of advanced electrocatalysts, endowing it in first-rank electrocatalyst.     

Co-free La0.6Sr0.4Fe0.9Nb0.1O3-δ symmetric electrode for hydrogen and carbon monoxide solid oxide fuel cell

Co-free La_0.6Sr_0.4FeO_3-δ (LSFNb₀) and La_0.6Sr_0.4Fe_0.9Nb_0.1O_3-δ (LSFNb_0.1) perovskite oxides were prepared by a standard solid-state reaction method. The structural stability and electrochemical performance of La_0.6Sr_0.4Fe_0.9Nb_0.1O_3-δ as both cathode and anode were studied. Nb dopant in LSFNb₀ significantly enhances the structural and chemical stability in anode condition. At 800 °C, the polarization resistances (Rp) of LSFNb_0.1 symmetric electrode based on YSZ electrolyte are 0.5 and 0.05 Ω cm² in H₂ and air, respectively. The peak power densities of LSFNb_0.1 based on LSGM electrolyte-supported SSOFCs are 934 and 707 mW cm⁻² at 850 °C in H₂ (3% H₂O) and dry CO, respectively. Moreover, the symmetric cell exhibits reasonable stability in both H₂ and CO fuel, suggesting that La_0.6Sr_0.4Fe_0.9Nb_0.1O_3-δ may be a potential symmetric electrode material for hydrogen and carbon monoxide SOFCs.     

Research progress on heat transfer enhancement technology of phase change energy storage

相变储能是通过相变材料吸/放热过程来实现能量储存的技术,它能够解决热量供需时间、空间和强度上的不匹配,并以其高储能密度成为储能领域的研究热点,但由于相变材料的热导率较低,使其应用受到限制。针对相变储能材料熔化/凝固过程中热导率低引起的传热速率慢的问题,从优化储能设备结构、添加剂提高相变材料热导率以及联合强化传热技术三方面综述国内外相变材料储能强化传热技术的最新进展。通过比较各种强化传热方式的优劣,实验和模拟均显示复合强化传热即可解决相变材料热导率低,又增大传热面积,从而提高相变材料的传热性能;多孔金属作为导热添加剂增强导热效果更好;并提出了相变储能强化传热技术未来需要解决的相关技术难题。     

基于中枢解耦与演化博弈的多农业园区综合能源系统优化运行

农业园区用能需求集中且源荷多元化,当多个农业园区缺少合理运行方法且分布式接入农网,势必会对农业园区效益与农网安全产生不利影响.针对上述问题,提出一种基于中枢解耦与演化博弈的多农业园区综合能源系统(agricultural integrated energy system,AIES)优化运行方法.首先,构建含电气热的AI...     

沙葱总黄酮水洗组分的体外抗炎活性

本实验在体外应用脂多糖（lipopolysaccharides,LPS）诱导小鼠腹腔巨噬细胞建立炎症模型的基础上,探讨沙葱总黄酮水洗组分的体外抗炎活性。应用CCK-8法检测0、50、100、200、400、800 μg/mL沙葱总黄酮水洗组分对小鼠腹腔巨噬细胞增殖活力的影响;将细胞分为空白对照组、LPS应激模型组及不同质量浓度沙葱总黄酮水洗组分预处理组,采用Griess法及酶联免疫吸附测定法分别测定各处理组细胞上清液中NO浓度和肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）、白细胞介素（interleukin,IL）-1β、IL-6、IL-10的质量浓度,反转录实时荧光定量聚合酶链式反应法检测各处理组细胞中诱导型一氧化氮合酶（inducible nitric oxide synthase,iNOS）、TNF-α、IL-1β、IL-6、IL-10、髓样分化蛋白（myeloid differential protein,MyD）88、核因子 κB（nuclear factor κB,NF-κB）mRNA的表达水平。结果显示：与对照组相比,沙葱总黄酮水洗组分在50～800 μg/mL时对小鼠腹腔巨噬细胞无明显细胞毒性作用。与LPS应激模型组相比,沙葱总黄酮水洗组分能够极显著抑制促炎介质NO、TNF-α、IL-1β、IL-6质量浓度及其mRNA的表达（P＜0.01或P＜0.001）;高度显著提高抗炎细胞因子IL-10质量浓度及其mRNA的表达（P＜0.001）,且呈剂量依赖效应;极显著降低MyD88、NF-κB mRNA的表达水平（P＜0.01或P＜0.001）。由此得出,沙葱总黄酮水洗组分对LPS诱导的小鼠腹腔巨噬细胞具有抗炎作用,其抗炎活性可能是通过抑制促炎性介质NO、TNF-α、IL-1β、IL-6的分泌并提高抗炎性细胞因子IL-10的质量浓度实现的,其作用机制可能与NF-κB信号通路有关。