Phosphorene: a Potential 2D Material for Highly Efficient Polysulfide Trapping and Conversion

Effectively trapping lithium polysulfide species and accelerating the reaction conversion kinetics are the main strategies to improve the performance of lithium-sulfur(Li-S) batteries. Since the researchers found in 2014 that two-dimensional(2D) phosphorene nanosheets could be exfoliated from the bulk black phosphorus, numerous researches have been devoted to exploring the phosphorene with unique properties for the application in Li-S batteries. In this review, we summarize the recent theoretical and experimental progress of phosphorene for Li-S batteries. Besides, we also introduce the relationship between the interfacial interaction on phosphorene and the performance enhancement of Li-S batteries. Furthermore, future challenges and remaining opportunities for phosphorene in Li-S batteries are finally discussed.     

Effects of synthesis parameters on the microstructure and phase structure of porous 316L stainless steel supported TiO2 membranes

Porous stainless steel (PSS) supported TiO₂ membrane was synthesized from colloidal TiO₂ sol by the sol–gel technique. Morphology and phase structure of the obtained membranes were regulated through optimizing the synthesis parameters including organic binders, aging periods of the parent sol and concentrations of the casting solutions as well as the sintering temperatures. Polyvinyl alcohol (PVA) 1750 was found to be feasible to fabricate TiO₂ membrane with relatively flat surface and homogeneous morphology without crack. The aging period of the parent sol, which was revealed to be very important to the morphology of the particles deposited in the membranes on PSS, was decided to be 24 h. The concentration, under which the membranes could avoid macro-pores and have a uniform thickness of approximately 8 μm, was regulated to 0.0036 mol/l. Besides, a homogeneous microstructure with grain sizes of 0.08–0.2 μm was obtained in the membrane with a pure rutile phase when sintered at 850 °C. The obtained PSS supported TiO₂ membrane with homogeneous microstructure and rutile phase may be very promising for practical applications.     

基于第一性原理方法研究ReOx在ReOx-Rh/ZrO2和ReOx-Ir/ZrO2催化的甘油氢解反应中的作用机制

采用密度泛函理论研究了ZrO₂负载的Ru基、Rh基以及Re改性的Rh基、Ir基催化剂上甘油氢解生成1,2-丙二醇和1,3-丙二醇的热力学过程, 重点考察了ReO_x调变催化剂活性和选择性的作用机制. 结果表明, Ru/ZrO₂和Rh/ZrO₂催化剂上甘油分解经由脱水-加氢反应途径, 1,2-丙二醇的生成是热力学有利过程, 其中Ru基催化剂活性更高. 在Re修饰的Rh基和Ir基催化剂上, 反应遵循直接氢解机理, 其中金属表面解离的氢原子进攻ReO_x团簇上与醇盐紧邻的C-O键是催化甘油转化为丙二醇最核心的步骤. ReO_x-Rh/ZrO₂催化剂上1,2-丙二醇为主要产物, 并伴随1,3-丙二醇的生成, ReO_x的修饰则显著提高了Ir/ZrO₂催化剂上1,3-丙二醇选择性. 与单金属催化剂上发生的间接氢解机理相比, 修饰催化剂上1,3-丙二醇选择性的提高可主要归因于Rh(Ir)-Re协同催化的直接氢解反应过程, 其中羟基化铼官能团有利于末端醇盐中间体的生成. ReO_x-Ir/ZrO₂催化剂上较大的Ir-Re团簇使得末端金属醇盐的立体优选性比次级醇盐更为突出, 从而具有最高的1,3-丙二醇选择性.     

Existence and Concentration of Ground States of Coupled Nonlinear Schr(o)dinger Equations with Bounded Potentials

A 2-coupled nonlinear Schr(o)dinger equations with bounded varying potentials and strongly attractive interactions is considered.When the attractive interaction is strong enough,the existence of a ground state for sufficiently small Planck constant is proved.As the Planck constant approaches zero,it is proved that one of the components concentrates at a minimum point of the ground state energy function which is defined in Section 4.     

具奇系数发展型p-Laplace不等方程整体解的不存在性

考虑两类带奇性系数发展型p-Laplace不等方程整体非负解的不存在性,也即要证明某些拟线性抛物型方程的非线性Liouville定理.通过先验估计,证明了整体解在某个带参数的函数空间中的不存在性.当只考虑连续整体解时,可选取不带参数的函数空间并证明整体解在其中的不存在性.     

Mechanistic Investigation and Conductance Modulation of a Metal-Molecule-Metal Junction via Extra Acid Addition

One important prerequisite for the fabrication of molecular functional device strongly relies on the understanding the conducting behaviors of the metal-molecule-metal junction that can respond to an external stimulus. The model Lewis basic molecule 4,4′-(pyridine-3,5-diyl)dibenzonitrile (DBP), which can react with Lewis acid and protic acid, was synthesized. Then, the molecular conducting behavior of DBP, DBP-B(C₆F₅)₃, and DBP-TfOH (DBP-B(C₆F₅)₃, and DBP-TfOH were produced by Lewis acid and protonic acid treatment of DBP) was researched and compared. Given that their identical physical paths for DBP, DBP-B(C₆F₅)₃, and DBP-TfOH to sustain charge transport, our results indicate that modifying the molecular electronic structure, even not directly changing the conductive physical backbone, can tune the charge transporting ability by nearly one order of magnitude. Furthermore, the addition of another Lewis base triethylamine (of stronger alkaline than DBP), to Lewis acid-base pair reverts the electrical properties back to that of a single DBP junction, that is constructive to propose a useful but simple strategy for the design and construction of reversible and controllable molecular device based on pyridine derived molecule.     

Phase and Interface Engineering of Platinum–Nickel Nanowires for Efficient Electrochemical Hydrogen Evolution

The design of high‐performance electrocatalysts for the alkaline hydrogen evolution reaction (HER) is highly desirable for the development of alkaline water electrolysis. Phase‐ and interface‐engineered platinum–nickel nanowires (Pt‐Ni NWs) are highly efficient electrocatalysts for alkaline HER. The phase and interface engineering is achieved by simply annealing the pristine Pt‐Ni NWs under a controlled atmosphere. Impressively, the newly generated nanomaterials exhibit superior activity for the alkaline HER, outperforming the pristine Pt‐Ni NWs and commercial Pt/C, and also represent the best alkaline HER catalysts to date. The enhanced HER activities are attributed to the superior phase and interface structures in the engineered Pt‐Ni NWs.     

色玻璃凝聚近似下极端相对论重离子碰撞中的双轻子和光子产生(英文)

在色玻璃凝聚胶子饱和框架下,研究了相对论重离子碰撞中的双轻子和光子产生。在胶子饱和区域,在微扰近似(kT-因子化近似) 下低转移动量双轻子和光子的主要产生机制是胶子-胶子相互作用。在RHIC 和LHC 能量区域的相对论重离子碰撞中,饱和动量的值远远大于量子色动力学禁闭标度ΛQCD,这使得αs?1。此时,当转移动量小于饱和动量Qs 时质子和原子核的胶子密度值就会很高,双轻子和光子的不变产生横截面会由于饱效应而得到增强。数值结果给出在RHIC 和LHC 能量区域的pp, pA 和AA碰撞中,来源于色玻璃凝聚的低转移动量双轻子和光子产生贡献是显著的。We investigate inclusive dileptons and photons production in relativistic heavy ion collisions based on the idea of gluon saturation in the color glass condensate (CGC) framework. In the gluon saturation region, the dominant mechanism for low-pT dileptons and photons production in the perturbative approach (the kT-factorization approach) is gluon-gluon interaction. At Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies, the value of saturation momentum becomes larger than the Quantum Chromodynamics (QCD) confinement scale ΛQCD for relativistic heavy ion collisions, which implies that αs?1. In this state, the gluon density for proton and nucleus with transverse momentum less than the saturation momentum Qs will reach a high value, and the invariant cross-section for dileptons and direct photons is further enhanced by saturation effects. The numerical results indicate that the production of low-pT dileptons and photons from the color glass condensate becomes prominent in pp, pA, and AA collisions at RHIC and LHC  Energies.     

半花菁衍生物LB膜的光致荧光特性研究

通过改变半花菁的亲水基团与疏水基团而得到了四种半花菁衍生物 ,利用稳态和时间分辨荧光研究了不同亲水基团与疏水基团对半花菁衍生物光学特性的影响.主要包括半花菁衍生物在LB膜中的聚集特性;亲水基团与疏水基团对半花菁衍生物激发态寿命的影响等.