Application-oriented hydrolysis reaction system of solid-state hydrogen storage materials for high energy density target:A review

Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry chain.Among all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen capacity.Hydrolysis reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable applications.At present,most of review work focuses on the improvement of material performance,especially the catalysts design.This part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical applications.Different operation modes of hydrolysis reaction have an impact on hydrogen capacity to various degrees.For example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the reaction.Therefore,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS materials.In this paper,the operation modes of hydrolysis reaction and their practical applications are mainly reviewed.The implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy density.The current challenges and future directions are also discussed.

近紫外白光LED用KBa_2(NbO_3)_5∶Eu^(3+)红色荧光粉的合成与发光性能

采用高温固相法制备了稀土离子Eu3+掺杂KBa2(Nb O3)5(KBN)新型红色荧光粉,用X射线衍射谱(XRD)、扫描电镜(SEM)、荧光光谱(PL)对其晶体结构和发光性能进行了表征。XRD表明KBa2(Nb O3)5的晶体结构没有随着Eu3+掺杂量的改变而改变,随着Eu3+掺杂量的增加,各衍射峰的位置向高衍射角偏移;SEM表明荧光粉样品晶体发育较好;荧光光谱表明Eu3+掺杂KBa2(Nb O3)5荧光粉在398 nm有最强激发峰,发射光谱的最强峰随Eu3+浓度增加从593 nm(5D0→7F1)变为613 nm(5D0→7F2)。当Eu3+的掺杂摩尔分数x在0.1~0.5范围内时,发光强度和红光色纯度随着Eu3+的浓度增加而增加,无浓度猝灭现象出现。

Modified room temperature solid-state synthesis of yttria-stabilized zirconia(YSZ) nano-powders for solid oxide fuel cells

High-performance solid oxide fuel cell(SOFC) is in urgent need of high-quality electrolyte powders with high reactivity and chemical uniformity.Here,8 mol% Y_(2)O_(3) doped ZrO_(2)(YSZ) nano-powders were synthesized by an improved solid-state reaction method at ambient temperature,and were applied to the fabrication of SOFC electrolytes.YSZ nano-powders show average grain sizes of ^(2)0 nm and high dispersibility,which is comparable with or even better than some other chemical methods.Benefitting from their high reactivity,dense YSZ electrolytes(relative density of 97.9%) can be obtained at a relatively low sintering temperature of 1400℃.The optimized electrical conductivity reaches up to a high value of0.034 S/cm at 800 0C in air.The anode supported single cell with the construction of Ni-YSZ/YSZ/Sm_(0.2)Ce_(0.8)O_(2-δ)(SDC)/La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF) exhibits the peak power density of 0.827 W/cm^(2) at800℃ while taking wet H_(2) as fuels and ambient air as oxidants.

High entropy(Yb0.25Y0.25Lu0.25Er0.25)2SiO5 with strong anisotropy in thermal expansion

A novel high entropy(HE) rare earth monosilicate(Yb0.25Y0.25Lu0.25Er0.252 SiO5 was synthesized by solid-state reaction method.X-ray diffraction and scanning electron microscopy analysis indicate that a single solid solution is formed with homogeneous distribution of rare-earth elements.HE(Yb0.25Y0.25Lu0.255 Er0.252 SiO5 exhibits excellent phase stability and anisotropy in thermal expansion.The coefficients of thermal expansion(CTEs) in three crystallographic directions are:αa=(2.57±0.07)×10^-6 K^-1,αb=(8.07±0.13)×10^-6 K^-1,αc=(9.98±0.10)×10^-6 K^-1.The strong anisotropy in thermal expansion is favorable in minimizing the coating/substrate mismatch if preferred orientation of HE(Yb0.25Y0.25Lu0.25Er0.252 SiO5 is controlled on either metal or ceramic substrate.

Crystal structures,two-photon absorption and theoretical calculation of a series of bis-vinylpyridine compounds synthesized by one-step solid state reaction

Three bis-vinylpyridine compounds (4,4′-bis(2-vinylpyridine)biphenyl L1,4,4′-bis(3-vinylpyridine) biphenyl L2,and 4,4′-bis (4-vinylpyridine)biphenyl L3) were synthesized by one-step solid-state reactions at room temperature,giving nearly quantitative yields. The compounds obtained were fully characterized by IR,MS and NMR spectroscopies. The structures of L2 and L3 were determined by single crystal X-ray diffraction analysis. No noticeable solvatochromism was observed in either one-photon absorption or one-photon excited fluorescence spectra. All of the compounds have high fluorescence quantum yields and long fluorescence lifetime. The linear and nonlinear optical properties of the compounds were investigated both experimentally and theoretically. Interestingly,the position of the nitrogen atom from pyridine influences their two-photon absorption across-sections.

Synthesis and luminescence properties of novel Ce^3＋-doped Yb3Al5-xGaxO12 garnets with very fast decay time

A novel series of Ce^3＋-doped Yb3 Al（5-x）GaxO（12）（x = 0, 1,2, 3,4, 5） powders of ytterbium aluminum gallium garnets were synthesized by high temperature solid-state reaction in a carbon reducing atmosphere. The ytterbium aluminum garnets were characterized by X-ray powder diffraction, UV-Vis diffuse reflectance spectra, photoluminescence spectra and decay curves. Moreover, the substitution effect for the Al^3＋ sites with Ga^3＋ in 0.5 at%Ce：Yb3 Al（5-x）GaxO（12）（x = 0,1, 2, 3, 4, 5） garnets were discussed. With the increase of Ga^3＋ ion concentration, the visible absorption peaks within 400-450 nm have blue shift phenomenon,while the absorption peaks in the range of 330-350 nm and the absorption band edge red shifts.Furthermore, the short decay times are very short with less than 10 ns due to the Yb^3＋ ＋ Ce^3＋→ Yb^2＋ ＋ Ce^4＋ electron transfer reaction.