Low carbon alcohol fuel electrolysis of hydrogen generation catalyzed by a novel and effective Pt–CoTe/C bifunctional catalyst system

Low carbon alcohol fuels electrolysis under ambient conditions is promising for green hydrogen generation instead of the traditional alcohol fuels steam reforming technique,and highly efficient bifunctional catalysts for membrane electrode fabrication are required to drive the electrolysis reactions.Herein,the efficient catalytic promotion effect of a novel catalyst promoter,CoTe,on Pt is demonstrated for low carbon alcohol fuels of methanol and ethanol electrolysis for hydrogen generation.Experimental and density functional theory calculation results indicate that the optimized electronic structure of Pt–CoTe/C resulting from the synergetic effect between Pt and CoTe further regulates the adsorption energies of CO and H*that enhances the catalytic ability for methanol and ethanol electrolysis.Moreover,the good water activation ability of CoTe and the strong electronic effect of Pt and CoTe increased the tolerance ability to the poisoning species as demonstrated by the CO-stripping technique.The high catalytic kinetics and stability,as well as the promotion effect,were also carefully discussed.Specifically,71.9%and 75.5%of the initial peak current density was maintained after 1000 CV cycles in acid electrolyte for methanol and ethanol oxidation;and a low overpotential of 30 and 35 mV was required to drive the hydrogen evolution reaction in methanol and ethanol solution at the current density of 10 mA cm^(-2).In the two-electrode system for alcohol fuels electrolysis,using the optimal Pt–CoTe/C catalyst as bi-functional catalysts,the cell potential of 0.66 V(0.67 V)was required to achieve 10 mA cm^(-2) for methanol(ethanol)electrolysis,much smaller than that of water electrolysis(1.76 V).The current study offers a novel platform for hydrogen generation via low carbon alcohol fuel electrolysis,and the result is helpful to the catalysis mechanism understanding of Pt assisted by the novel promoter.

MoP-NC纳米球负载Pt纳米粒子用于高效甲醇电解

实现绿色甲醇电解制氢需要高效的双功能催化剂。本文采用热处理结合乙二醇还原法成功制备了MoP-NC纳米球负载的超细Pt纳米粒子(平均粒径为2.53 nm)复合催化剂(Pt/MoP-NC)用于高效甲醇电解制氢。MoP-NC纳米球不仅能提高Pt纳米粒子的分散性并且增强Pt的抗中毒能力。电化学测试表明Pt/MoP-NC催化剂在酸性甲醇氧化反应(MOR)和析氢反应(HER)中具有较高的催化性能;其中,MOR的正向扫描峰值电流密度为90.7 m A·cm^(-2),是商业Pt/C催化剂的3.2倍,在10 mA·cm^(-2)的电流密度下,HER的过电位低至30 m V,与商业Pt/C接近。由Pt/MoP-NC||Pt/MoP-NC组装的两电极电解槽驱动10 mA·cm^(-2)的电流密度仅需要0.67 V的电压,比相同条件下电解水的电压低1.02 V,大大降低了能量输入。Pt/MoP-NC的高催化性能主要来源于Pt活性中心与相邻层状多孔球形结构的MoP-NC载体之间电子效应及配体效应引起的抗一氧化碳中毒能力的提升和含氧物种的容易生成。

Emerging MoS_(2)Wafer-Scale Technique for Integrated Circuits

As an outstanding representative of layered materials,molybdenum disulfide(MoS_(2))has excellent physical properties,such as high carrier mobility,stability,and abundance on earth.Moreover,its reasonable band gap and microelectronic compatible fabrication characteristics makes it the most promising candidate in future advanced integrated circuits such as logical electronics,flexible electronics,and focal-plane photodetector.However,to realize the all-aspects application of MoS_(2),the research on obtaining high-quality and large-area films need to be continuously explored to promote its industrialization.Although the MoS_(2)grain size has already improved from several micrometers to sub-millimeters,the high-quality growth of wafer-scale MoS_(2)is still of great challenge.Herein,this review mainly focuses on the evolution of MoS_(2)by including chemical vapor deposition,metal–organic chemical vapor deposition,physical vapor deposition,and thermal conversion technology methods.The state-of-the-art research on the growth and optimization mechanism,including nucleation,orientation,grain,and defect engineering,is systematically summarized.Then,this review summarizes the wafer-scale application of MoS_(2)in a transistor,inverter,electronics,and photodetectors.Finally,the current challenges and future perspectives are outlined for the wafer-scale growth and application of MoS_(2).

Recent advancement and future challenges of photothermal catalysis for VOCs elimination:From catalyst design to applications

Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of photothermal catalytic removal of volatile organic compounds(VOCs)by nano-catalysts in recent years is systematically reviewed.First,the fundamentals of photothermal catalysis and the fabrication of catalysts are described,and the design strategy of optimizing photothermal catalysis performance is proposed.Second,the performance for VOC degradation with photothermal catalysis is evaluated and compared for the batch and continuous systems.Particularly,the catalytic mechanism of VOC oxidation is systematically introduced based on experimental and theoretical study.Finally,the future limitations and challenges have been discussed,and potential research directions and priorities are highlighted.A broad view of recent photothermal catalyst fabrication,applications,challenges,and prospects can be systemically provided by this review.

用于生物医学应用的基于微藻的生物杂化材料的合理设计和开发

微藻是一种体积微小的真核生物,可通过叶绿素a的光合作用将二氧化碳转化为多种生物活性物质。在过去的十年中,有关活体微藻和其他生物相容性成分组成的生物杂化材料在解决许多医学难题中显示出巨大的潜力,如肿瘤治疗、组织重建和药物输送。固定在常规生物材料中的微藻可以长时间维持其光合活性从而在局部提供氧气,同时也可作为调节细胞活性的生物相容性界面材料。微藻的运动性还激发了生物杂交机器人的发展,其中药物分子可通过非共价键吸附结合至微藻表面,并通过精确控制其运动轨迹将药物输送到目标区域。此外,微藻的自发荧光、趋光性和生物质生产可以整合到具有多种功能的新型生物杂化材料的设计中;通过基因工程改造的微藻可以赋予生物杂交材料新的特性,如特异性细胞靶向能力和从藻类细胞中局部释放重组蛋白——这些技术技术有望促进微藻基生物杂交材料(MBBM)在多个生物医学领域的临床应用。本文总结了MBBM的制造、生理学和运动能力;然后,回顾了MBBM近年来在生物医学领域的典型应用报告;最后,对MBBM的挑战和未来前景进行了讨论。

p53 DNA结合域与抗癌多肽的拉伸分子动力学研究(英文)

研究发现,取自蓝铜蛋白azurin的一段多肽p28能够进入癌细胞,结合到肿瘤抑制因子p53的DNA结合域上,进而增加p53的抗癌能力.本工作中,通过拉伸分子动力学方法,在原子尺度上研究了p28-p53 DBD复合物的解离过程.分析结果显示复合物的解离过程遵循着一定的分离顺序.对解离力的分析以及对沿着解离路径的不可逆做功的计算,使我们能够从复合物的能量地貌中提取有用的信息,而这些信息也决定了复合物的解离过程.

Recent Progress in Emerging Two‑Dimensional Transition Metal Carbides

As a new member in two-dimensional materials family,transition metal carbides(TMCs)have many excellent properties,such as chemical stability,in-plane anisotropy,high conductivity and flexibility,and remarkable energy conversation efficiency,which predispose them for promising applications as transparent electrode,flexible electronics,broadband photodetectors and battery electrodes.However,up to now,their device applications are in the early stage,especially because their controllable synthesis is still a great challenge.This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure,property,synthesis and applicability of TMCs.Finally,the current challenges and future perspectives are outlined for the application of 2D TMCs.

Ultrathin Ti_(3)C_(2)T_(x)（MXene） Nanosheet-Wrapped NiSe_(2) Octahedral Crystal for Enhanced Supercapacitor Performance and Synergetic Electrocatalytic Water Splitting

Metal selenides,such as NiSe2,have exhibited great potentials as multifunctional materials for energy storage and conversation.However,the utilization of pure NiSe2 as electrode materials is limited by its poor cycling stability,low electrical conductivity,and insufficient electrochemically active sites.To remedy these defects,herein,a novel NiSe2/Ti3C2Tx hybrid with strong interfacial interaction and electrical properties is fabricated,by wrapping NiSe2 octahedral crystal with ultrathin Ti3C2Tx MXene nanosheet.The NiSe2/Ti3C2Tx hybrid exhibits excellent electrochemical performance,with a high specific capacitance of 531.2 Fg-1 at1 A g-1 for supercapacitor,low overpotential of 200 mV at 10 mA g-1,and small Tafel slope of 37.7 mV dec-1 for hydrogen evolution reaction(HER).Furthermore,greater cycling stabilities for NiSe2/Ti3C2Tx hybrid in both supercapacitor and HER have also been achieved.These significant improvements compared with unmodified NiSe2 should be owing to thestrong interfacial interaction between NiSe2 octahedral crystal and Ti3C2Tx MXene,which provides enhanced conductivity,fast charge transfer as well as abundant active sites,and highlight the promising potentials in combinations of MXene with metal selenides for multifunctional applications such as energy storage and conversion.

Atomically Dispersed Fe-N_4 Modified with Precisely Located S for Highly Efficient Oxygen Reduction

Immobilizing metal atoms by multiple nitrogen atoms has triggered exceptional catalytic activity toward many critical electrochemical reactions due to their merits of highly unsaturated coordination and strong metal-substrate interaction.Herein,atomically dispersed Fe-NC material with precise sulfur modification to Fe periphery(termed as Fe-NSC) was synthesized,X-ray absorption near edge structure analysis confirmed the central Fe atom being stabilized in a specific configuration of Fe(N3)(N-C-S).By enabling precisely localized S doping,the electronic structure of Fe-N4 moiety could be mediated,leading to the beneficial adjustment of absorption/desorption properties of reactant/intermediate on Fe center.Density functional theory simulation suggested that more negative charge density would be localized over Fe-N4 moiety after S doping,allowing weakened binding capability to *OH intermediates and faster charge transfer from Fe center to O species.Electrochemical measurements revealed that the Fe-NSC sample exhibited significantly enhanced oxygen reduction reaction performance compared to the S-free Fe-NC material(termed as Fe-NC),showing an excellent onset potential of 1.09 V and half-wave potential of 0.92 V in 0.1 M KOH.Our work may enlighten relevant studies regarding to accessing improvement on the catalytic performance of atomically dispersed M-NC materials by managing precisely tuned local environments of M-Nx moiety.

Electron-enriched Pt induced by CoSe_(2)promoted bifunctional catalytic ability for low carbon alcohol fuel electro-reforming of hydrogen evolution

Alcohol fuel electro-reforming is promising for green hydrogen generation while developing efficient bifunctional catalysts for alcohol fuel electrolysis is still very tricky.Herein,we for the first time proposed the electron-enriched Pt induced by CoSe_(2)has an efficient bi-functional catalytic ability for alcohol fuels electro-reforming of hydrogen in acid electrolytes.The theoretical calculation revealed the advantages of electron-enriched Pt surface for the adsorption of intermediate,which is well supported by spectroscopic analysis and CO-stripping techniques.Largely improved catalytic performances of activity,durability,and kinetics are demonstrated compared to the conventional alloy system and commercial Pt/C catalyst,due to the efficient synergism of Pt and CoSe_(2);the peak current density of Pt/CoSe_(2)for methanol(ethanol)oxidation is 87.61(48.27)m A cm^(-2),which is about 3.3(2.0)times higher than that of Pt/C catalyst and 2.0(1.5)times that of the traditional PtCo alloy catalysts.Impressively,about 80%of the initial current was found after 1000 cycles of stability test for alcohol fuel oxidation of Pt/CoSe_(2)catalyst,higher than that of Pt/C(ca.50%)and PtCo catalyst(65%).When Pt/CoSe_(2)catalyst serviced as bi-functional catalysts for electrolyzer,a low cell potential of 0.65(0.78)V for methanol(ethanol)electrolysis was required to reach 10 m A cm^(-2),which was about 1030(900)m V less than that of conventional water electrolysis using Pt/C as the catalyst.The current result is instructive for the design of novel bifunctional catalyst and the understanding of hydrogen generation via alcohol fuel electro-reforming.

Atomically dispersed catalysts for small molecule electrooxidation in direct liquid fuel cells

Direct liquid fuel cells(DLFCs) have received increasing attention because of their high energy densities,instant recharging abilities, simple cell structure, and facile storage and transport. The main challenge for the commercialization of DLFCs is the high loading requirement of platinum group metals(PGMs) as catalysts. Atomically dispersed catalysts(ADCs) have been brought into recent focus for DLFCs due to their well-defined active sites, high selectivity, maximal atom-utilization, and anti-poisoning property. In this review, we summarized the structure–property relationship for unveiling the underlying mechanisms of ADCs for DLFCs. More specifically, different types of fuels used in DLFCs such as methanol, formic acid,and ethanol were discussed. At last, we highlighted current challenges, research directions, and future outlooks towards the practical application of DLFCs.

Investigation on Bioactivity of Titanium DioXide Thin Films Fabricated by Electron Cyclotron Resonance Plasma Aided Pulsed Laser Deposition

Titanium dioxide thin films with a rutile crystallinite size around 20 nm were fabri- cated by pulsed laser deposition （PLD） aided with an electron cyclotron resonance （ECR） plasma. With annealing treatment, the crystal size of the rutile crystallinite increased to 100 nm. The apatite-forming ability of the films as deposited and after annealing was investigated in a kind of simulated body fluid with ion concentrations nearly equal to those of human blood plasma. The results indicate that ECR aided PLD is an effective way both to fabricate bioactive titanium dioxide thin films and to optimize the bioactivity of titanium dioxide, with both crystal size and defects of the film taken into account.

ZrO_2/Graphene Nanocomposites Synthesized in Supercritical Fluids: Highly Efficient Chemical Sensor Material for Ethanol

ZrO2/Graphene nanocomposites are fabricated from graphene oxide by one-step, green, facile and low-cost SCCO2 method. The as-prepared nanocomposites are characterized by means of X-ray photoelectron, transmission electron microscopy and catalytic chemiluminescence measurement. The ZrO2 nanoparticles with size of several nanometers are uniformly coated on the graphene surface. The chemiluminescence characteristic to ethanol of the as-prepared nanocomposite paper is also investigated. The nanocomposite paper obtained displays high catalytic chemiluminescence sensitivity and highly selectivity to the ethanol gas. This study provides a facile, green and low-cost route to prepare nanoscopic gas sensing devices with application in safe protection, food fermentation, medical process and traffic safe.

Dual neuronal response to tumor necrosis factor-alpha following spinal cord injury

BACKGROUND： Numerous studies have shown that tumor necrosis factor α （TNF-α） is closely correlated with spinal cord injury （SCI）, but the mechanisms of TNF-α and therapeutic treatments for SCI are still poorly understood. OBJECTIVE： To determine the role of TNF-α in the pathogenesis of SCI. DESIGN, TIME AND SETTING： An in vivo experiment based on genetically engineered animals was performed at the Medical University of South Carolina, Charleston, South Carolina, USA, between June 2007 and October 2008. MATERIALS： TNF-α transgenic rats （Xenogen Biosciences in Cranbury, New Jersey, USA） were utilized in this study. METHODS： TNF-α transgenic （tg） and wild-type （WT） rats underwent a complete single-level laminectomy at the 10^th thoracic vertebra （T10）. MAIN OUTCOME MEASURES： Motor function of rat hindlimb was assessed using the Basso, Beattie, and Bresnahan hindlimb locomotor rating scale. Histological evaluation of spinal cord tissue loss was conducted. Immunohistochemistry for astrocytes, microglia/macrophages, and TNF receptors （TNFRs） was performed on spinal cord tissue sections. TNF-α mRNA expression was detected by real-time polymerase chain reaction. The concentrations of nerve growth factor （NGF） and brain-derived neurotrophic factor （BDNF） in the supernatant were determined using an enzyme-linked immunosorbent assay kit for rat NGF or BDNF, respectively. The rats were injected subcutaneously with etanercept to verify that TNF-α was the direct effect of the modulation of behavioral and neurodegenerative outcomes in the TNF-α tg rats. RESULTS： TNF-α tg rats showed higher expression of TNF-α mRNA in the spinal cord prior to SCI. TNF-α tg rats showed worse motor deficits than WT rats in the acute period （〈 3 days） after SCI （P 〈 0.01）, while in the chronic period, TNF-α tg rats exhibited persistent elevated baseline levels of TNF-α mRNA and improved recovery in motor function and tissue healing compared to WT rats （P 〈 0.01 ）. Following SCI, the number of microglia/macrophages in TNF-α tg rat was always greater than in WT rat （P 〈 0.01）. There were no significant differences in NGF and BDNF levels in the supernatant of spinal cord homogenates. TNFR1 expression was significantly greater in the TNF-α tg rats compared to the WT rats （P 〈 0.01）. However, TNFR2 expression did not reveal a significant increase in the TNF-α tg rats compared to the WT rats. Finally, treatment with etanercept reduced injury acutely, but exacerbated the injury chronically. CONCLUSION： Overexpression of TNF-α is deleterious in the acute phase, but beneficial in the chronic phase in the response to SCI. The role of TNF-α post-injury may depend on TNF-α expression in the spinal cord and its differential binding to TNFRI. Our observations may have clinical relevance that antagonists or inhibitors of TNF-α could be administered within the early time window post-injury, and appropriate amounts of TNF-α could be administered during the chronic stage, in order to improve the final neurological recovery in patients with SCI.

A silazane additive for CsPbI_(2)Br perovskite solar cells

Adding additives into peroskite precursor solution has been proven as a simple and efficient strategy to improve the quality of peroskite films.In this work,we demonstrate an effective additive strategy to improve the quality of all-inorganic perovskite films by adding a novel silazane additive heptamethyldisilazane(HDMS).The power conversion efficiency(PCE)of the optimized devices is enhanced from 14.55%to 15.31%with an open-circuit voltage over 1.26 V due to the higher quality perovskite films with lower trap density after the incorporation of HDMS.More interestingly,the HDMS devices exhibit superior humidity and thermal stability compared with the control ones.This work provides a simple and efficient strategy to enhance the device performance and stability of all-inorganic perovskite solar cells,which could facilitate its commercialization.

Comparative study of various methods for extraction of multi-quantum wells Schottky diode parameters

In this work,forward current voltage characteristics for multi-quantum wells Al_(0.33)Ga_(0.67)As Schottky diode were measured at temperature ranges from 100 to 300 K.The main parameters of this Schottky diode,such as the ideality factor,barrier height,series resistance and saturation current,have been extracted using both analytical and heuristics methods.Differential evolution(DE),particle swarm optimization(PSO)and artificial bee colony(ABC)have been chosen as candidate heuristics algorithms,while Cheung technic was selected as analytical extraction method.The obtained results show clearly the high performance of DE algorithms in terms of parameters accuracy,convergence speed and robustness.

Cell Nanomechanics Based on Dielectric Elastomer Actuator Device

As a frontier of biology,mechanobiology plays an important role in tissue and biomedical engineering.It is a common sense that mechanical cues under extracellular microenvironment affect a lot in regulating the behaviors of cells such as proliferation and gene expression,etc.In such an interdisciplinary field,engineering methods like the pneumatic and motor-driven devices have been employed for years.Nevertheless,such techniques usually rely on complex structures,which cost much but not so easy to control.Dielectric elastomer actuators(DEAs)are well known as a kind of soft actuation technology,and their research prospect in biomechanical field is gradually concerned due to their properties just like large deformation(>100%)and fast response(<1 ms).In addition,DEAs are usually optically transparent and can be fabricated into small volume,which make them easy to cooperate with regular microscope to realize real-time dynamic imaging of cells.This paper first reviews the basic components,principle,and evaluation of DEAs and then overview some corresponding applications of DEAs for cellular mechanobiology research.We also provide a comparison between DEA-based bioreactors and current custom-built devices and share some opinions about their potential applications in the future according to widely reported results via other methods.

Modeling and Simulation of the Hydrodynamic Behavior in a High-Density Downer Reactor

The hydrodynamic behavior in a high-density downer reactor was studied. A two-fluid model based on the kinetic theory of granular flow with a k-ε turbulent model was developed to simulate the flow behavior in the system. This simulation achieved an averaged solid fraction in the bed as high as 18% in this operating regime. The flow development in high-density downer consists of 3 regions, which are first acceleration, second acceleration, and fully developed regions. In the fully developed region, the lateral distribution of the solid volume fraction is low and almost uniform in the center region with a high density peak near the wall region. Gas and solid velocities gradually increase toward the wall and form a peak near the wall region. In addition, the solid volume fraction, gas and solid velocities increase with solid circulation rate.

Single Molecule Applications of Quantum Dots

Fluorescent nanocrystals composed of semiconductor materials were first introduced for biological applications in the late 1990s. The focus of this review is to give a brief survey of biological applications of quantum dots (QDs) at the single QD sensitivity level. These are described as follows: 1) QD blinking and bleaching statistics, 2) the use of QDs in high speed single particle tracking with a special focus on how to design the biofunctional coatings of QDs which enable specific targeting to single proteins or lipids of interest, 3) a hybrid lipid-DNA analogue binding QDs which allows for tracking single lipids in lipid bilayers, 4) two-photon fluorescence correlation spectroscopy of QDs and 5) optical trapping and excitation of single QDs. In all of these applications, the focus is on the single particle sensitivity level of QDs. The high applicability of QDs in live cell imaging experiments held together with the prospects in localization microscopy and single molecule manipulation experiments gave QDs a promising future in single molecule research.

Recent advances in carbon dioxide selective hydrogenation and biomass valorization via single-atom catalysts

The utilization of fossil fuels has brought unprecedented prosperity and development to human society,but also caused environmental pollution and global warming triggered by excess greenhouse gases emission.For one thing,the excess emission of carbon dioxide(CO_(2)),which has a negative impact on global temperature and ocean acidity,needs to be controlled.For another,the depletion of fossil fuels will eventually force people to seek alternative carbon sources to maintain a sustainable economy.Thus,using renewable energy to convert CO_(2) and biomass into value-added chemicals and fuels is a promising method to overcome urgent problems.The hy-drogenation of CO_(2) is very important to mitigate the greenhouse effect caused by CO_(2),while biomass conversion can produce alternative renewable biofuels and green chemicals.As a kind of promising catalyst,heterogeneous single-atom catalyst(SAC)has received extensive attention in the past decades.SACs combine the advantages of homogeneous catalysts with uniform active sites and heterogeneous catalysts that are easily separable.In this review,we will give a comprehensive overview of the latest progress in CO_(2) selective hydrogenation and biomass conversion via SACs.