Improved Plasmonic Hot‑Electron Capture in Au Nanoparticle/Polymeric Carbon Nitride by Pt Single Atoms for Broad‑Spectrum Photocatalytic H_(2)Evolution

ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging issue.Herein,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this challenge.For the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) evolution.Furthermore,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer effect.Consequently,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,respectively.This work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.

Sulfur vacancies-induced“Electron Bridge”in Ni_(4)Mo/Sv-Zn_(x)Cd_(1-x)S regulates electron transfer for efficient H_(2)-releasing photocatalysis

Despite the existence of plentiful photocatalyst heterojunctions,their separation efficiency and charge flow precision remain low on account of lacking interfacial modulation.Herein,through a defect-induced heterojunction constructing strategy,Ni4Mo alloys were in-situ grown on the unsaturated coordinated sulfur atoms of sulfur vacancies-rich ZCS(Sv-ZCS)via interfacial Ni-S covalent bonds.The experimental and theoretical results reveal that these unsaturated sulfur atoms induced by sulfur vacancies vastly facilitate to anchor more Ni-Mo nanoparticles and form abundant Ni-S covalent bonds,meanwhile,these sulfur vacancies could form dual internal electric field(IEF)and work with Ni-S covalent bonds as“Electron Bridge”to further accelerate photoelectrons transfer,as well as promote the activation of water molecules and the desorption of hydrogen proton.Accordingly,the optimized Ni_(4)Mo/Sv-ZCS composite achieves an improved photocatalytic hydrogen evolution(PHE)rate of 94.69 mmol h^(-1)g^(-1)without an evident decrease after 6 cycles of photocatalytic tests,which is 21.2 and 1.94 times higher than those of Pt/ZCS and Ni_(4)Mo/ZCS,respectively.This tactic opens a new way for optimizing Zn_(x)Cd_(1-x)S-based heterojunctions by constructing sulfur vacancies and covalent bonds as“Electron Bridge”to enhance the activity of PHE.

Hydrophobic Small-Molecule Polymers as High-Temperature-Resistant Inhibitors in Water-Based Drilling Fluids

Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.

地方猪种的杂交利用方式以及轮回杂交在其中的应用

文章将地方猪种的种质特性特点、杂交利用方式以及轮回杂交在地方猪种中的利用等进行综述,以期为地方猪种的选育和利用提供建议及参考。

松辽黑猪、雷香猪、杜长大白猪肉质性状及肌肉营养成分比较研究

为了比较松辽黑猪、雷香猪、杜长大白猪肉质性状及肌肉营养成分,选取松辽黑猪、雷香猪、杜长大白猪进行屠宰,对肉质性状、肌肉氨基酸及脂肪酸含量进行测定,结果表明:松辽黑猪剪切力、肌内脂肪含量显著高于杜长大白猪(P<0.05),熟肉率显著高于雷香猪(P<0.05),雷香猪剪切力、肌内脂肪含量极显著高于杜长大白猪(P<0.01);松辽黑猪和雷香猪肌肉中丙氨酸含量极显著高于杜长大白猪(P<0.01),甘氨酸含量松辽黑猪显著高于雷香猪(P<0.05),极显著高于杜长大白猪(P<0.01);雷香猪亚油酸含量显著低于杜长大白猪(P<0.05)。文章对优质高端黑猪肉生产群体的选择提供了参考。

白藜芦醇对松辽黑猪精液冷冻的影响

试验旨在评价白藜芦醇(resveratrol,Res)对松辽黑猪公猪精液冷冻的影响。试验分为5组,分别为对照组(不添加Res)和Res处理组(在冷冻基础液中分别加入25μM、50μM、100μM、200μM浓度的Res)。采用手握法采集松辽黑猪精液,用5种冷冻基础液稀释,在25℃平衡1 h,17℃平衡2 h,4℃平衡3 h后灌装于0.5 mL细管中,在液氮上方3 cm处熏蒸10 min,保存在液氮罐中30 d后进行检测。样本解冻后分别检测精子活力、谷胱甘肽过氧化物酶(GSH-Px)活性、质膜完整性、过氧化氢酶(CAT)活性、顶体完整性、线粒体活性、活性氧簇(ROS)水平、DNA完整性、超氧化物歧化酶(SOD)活性以及丙二醛(MDA)水平。结果显示:与对照组相比,冷冻基础液中添加50μM Res可以显著提高冻融后精子的活力、SOD活性、质膜完整性、CAT活性、线粒体活性、GSH-Px活性、顶体完整性(P<0.05);可以显著降低精子ROS水平和MDA水平(P<0.05);添加Res对DNA完整性未表现出具有显著影响(P>0.05)。结论:猪精液冷冻前添加Res可改善冻融后精子质量,添加量50μM效果最佳,但Res是否可以改善公猪冷冻精液的体外受精及人工授精能力,有待于进一步的研究。

具有优异甲醇耐受性的Rh掺杂Pd Cu有序金属间化合物纳米粒子增强氧还原电催化

由于阴极催化剂有限的活性和耐久性以及甲醇渗透到阴极所导致的催化剂中毒问题,直接甲醇燃料电池(DMFCs)仍面临严峻的挑战。本文报道了一类新型的具有有序金属间结构的Rh掺杂PdCu纳米颗粒用于提高阴极氧还原反应(ORR)的活性、耐久性和甲醇耐受性。通过结合Rh原子掺杂以及有序金属间结构两者的优点,在碱性条件下,Rh掺杂Pd Cu金属间化合物催化剂在0.9 V电位下对氧还原质量活性相比商业Pt/C提高7.4倍。这种独特的结构还使其表现出出色的ORR耐久性,在连续20000个循环后的半波电位和质量活性几乎不变。此外,在苛刻的中毒环境下,仍可以保持Rh掺杂PdCu金属间化合物电催化剂高的氧还原催化活性。

Room-temperature solid phase surface engineering of BiOI sheets stacking g-C_(3)N_(4) boosts photocatalytic reduction of Cr(Ⅵ)

Cr(Ⅵ)-based compounds pollution have attracted global concern due to serious harm to humans and environment.Hence,it is crucial to exploit an effective technique to eliminate Cr(Ⅵ)in water.Herein,we in-situ grown BiOI on graphitic carbon nitride to prepare the BiOI/g-C_(3)N_(4)(BCN)direct Z-scheme heterojunction by solid phase engineering method at room temperature.Experimental result shown the photocatalytic activity of pure BiOI were obviously enhanced by constructing Z-scheme BCN heterostructure,and BCN-3 heterostructure exhibited the optimal photocatalytic degradation of RhB with 98%yield for 2.5 h and reduction of Cr(Ⅵ)with more than 99%yield for 1.5 h at pH=2.Stability test shows BCN-3 still kept more than 98%reduction efficiency after 6 cycles.In addition,we also studied the reduction mechanism that shown the.O_(2)^(-)radicals essentially helped to reduce the Cr(Ⅵ)in aqueous solution under illumination,verified the direct Z-scheme charge transfer path by X-ray photoelectron spectroscopy(XPS)and the free radical trapping experiment.The work open a new way for rationally designing photocatalyst heterostructure to reduce Cr(Ⅵ)to Cr(Ⅲ).

Study on Acoustically Transparent Test Section of Aeroacoustic Wind Tunnel

On the purpose of accurate data acquisition for the aeroacoustic testing mostly in open jet test section of aeroacoustic wind tunnel, the large scale anechoic chamber is specifically designed to build the low background noise environment. A newly acoustic test section is presented in this paper, of which the contour is similar as the closed test section, and the wall is fabricated by the fiber fabric, both the characteristics of closed and open jet test section of conventional wind tunnel are combined in it. By thoroughly researching on the acoustics and aerodynamics of this acoustically transparent test section, significant progress in reducing the background noises in test section and improving the ratio of energy of the wind tunnel and some other aspects have been achieved. Acoustically transparent test section behaves better in acoustics and aerodynamics than conventional acoustic test section because of their high definition in detecting the sound sources and great performance in transmitting sounds.

A general strategy for bimetallic Pt-based nano-branched structures as highly active and stable oxygen reduction and methanol oxidation bifunctional catalysts

The morphology and size of Pt-based bimetallic alloys are known to determine their electrocatalytic performance in reactions relevant to fuel cells.Here,we report a general approach for preparing Pt-M(M=Fe,Co and Ni)bimetallic nano-branched structure(NBs)by a simple high temperature solution-phase synthesis.As-prepared Pt-M NBs show a polycrystalline structure and are rich in steps and kinks on the surface,which promote them favorable bifunctional catalytic properties in acidic electrolytes,specifically in terms of the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR).Specially,Pt-Co NBs/C catalyst shows 6.1 and 5.3 times higher in specific activity(SA)and mass activity(MA)for ORR than state-of-the-art commercial Pt/C catalysts,respectively.Moreover,it exhibits a loss of 4.0%in SA and 14.4%in MA after 10,000 cycles of accelerated durability tests(ADTs)compared with the initial activities.In addition,we also confirmed the superior MOR activity of Pt-Co NBs/C catalyst in acidic electrolytes.For Pt-M NBs with other alloying metals,the ORR and MOR activities are both higher than commercial catalysts and are in the sequence of Pt-Co/C>Pt-Fe/C>Pt-Ni/C>commercial Pt/C(or PtRu/C).The improved activities and durability can benefit from the morphological and compositional effects.This synthesis approach may be applied to develop bifunctional catalysts with enhanced ORR and MOR properties for future fuel cells designs.

3D ordered mesoporous cobalt ferrite phosphides for overall water splitting

Developing low-cost and earth-abundant electrocatalysts with high performance for electrochemical water splitting is a challenging issue. Herein, we report a facile and effective way to fabricate three-dimension(3D) ordered mesoporous Co1-xFexP(x=0, 0.25, 0.5, 0.75) electrocatalyst.Benefiting from 3D ordered mesoporous pore channels and composition optimization, the Co0.75Fe0.25 P exhibits excellent electrocatalytic activities with low overpotentials of 270 and 209 mV at 10 mA cm^-2 for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER), respectively, in the alkaline electrolyte along with a durable electrochemical stability. In addition, as both the cathode and anode, the Co0.75Fe0.25P also exhibits superior electrolysis water splitting performance with only an applied voltage of 1.63 V to attain a current density of 10 m A cm^-2 without obvious decay for 18 h,indicating that the Co0.75Fe0.25P is an efficient electrocatalyst for overall water splitting.

Activating interfacial S sites of MoS_(2) boosts hydrogen evolution electrocatalysis

The hydrogen evolution reaction(HER)of molybdenum disulfide(MoS_(2))is limited in alkaline and acid solution because the active sites are on the finite edge with extended basal plane remaining inert.Herein,we activated the interfacial S sites by coupling with Ru nanoparticles on the inert basal plane of MoS_(2)nanosheets.The density functional theory(DFT)calculation and experimental results show that the interfacial S electronic structure was modulated.And the results of∆G H*demonstrate that the adsorption of H on the MoS_(2)was also optimized.With the advantage of interfacial S sites activation,the Ru-MoS_(2)needs only overpotential of 110 and 98 mV to achieve 10 mA·cm^(–2)in both 0.5 M H_(2)SO_(4)and ^(1) M KOH solution,respectively.This strategy paves a new way for activating the basal plane of other transition metal sulfide electrocatalysts for improving the HER performance.

Hierarchical mesoporous Co_3O_4@ZnCo_2O_4 hybrid nanowire arrays supported on Ni foam for high-performance asymmetric supercapacitors

In this paper, hierarchical mesoporous Co3O4@ZnCo2O4 hybrid nanowire arrays（NWAs） on Ni foam were prepared through a two-step hydrothermal process associated with successive annealing treatment. The Co3O4@ZnCo2O4 hybrid NWAs exhibited excellent electrochemical performances with a high specific capacity of 1,240.5 C g^-1 at a current density of 2 mA cm^-2, with rate capability of 59.0%shifting from 2 to 30 mA cm^-2, and only a 9.1% loss of its capacity even after 3,000 cycles at a consistent current density of 10 mA cm^-2. An asymmetric supercapacitor（Co3O4@ZnCo2O4 NWAs｜｜activated carbon） was fabricated and exhibited a high specific capacity of 168 C g^-1 at a current density of 1 A g^-1. And a preferable energy density of 37.3 W h kg^-1 at a power density of 800 W kg^-1 was obtained. The excellent electrochemical performances indicate the promising potential application of the hierarchical mesoporous Co3O4@ZnCo2O4 hybrid NWAs in energy storage field.

INFER OBJECTIVE FUNCTION OF GLYCEROL METABOLISM IN KLEBSIELLA PNEUMONIAE BASING ON BILEVEL PROGRAMMING

Mathematical modelling of cellular metabolism plays an important role in understandingbiological functions and providing identification of targets for biotechnological modification.This paperproposes a nonlinear bilevel programming(NBP)model to infer the objective function of anaerobicglycerol metabolism in Klebsiella Pneumoniae(K.Pneumoniae)for 1,3-propanediol(1,3-PD)production.Based on the Kuhn-Tucker optimality condition of the lower level problem,NBP is transformedinto a nonlinear programming with complementary and slackness conditions.The authors give the existencetheorem of solutions to NBP.An efficient algorithm is proposed to solve NBP and its convergenceis also simply analyzed.Numerical results reveal some interesting conclusions,e.g.,biomass productionis the main force to drive glycerol metabolism,and the objective functions,which are obtained in termof several different groups of flux distributions,are similar.

Affinity-guided protein conjugation: the trilogy of covalent protein labeling, assembly and inhibition

Specific and dynamic biological interactions pave the blueprint of signal networks in cell. For example, a great variety of specific protein-ligand interactions define how intracellular signals flow. Taking advantage of the specificity of these interactions, we postulate an "affinity-guided covalent conjugation" strategy to lock binding ligands through covalent reactions between the ligand and the receptor protein. The presence of a nucleophile close to the ligand binding site of a protein is sine qua none of this reaction. Specific noncovalent interaction of a ligand derivative(which contains an electrophile at a designed position) to the ligand binding site of the protein brings the electrophile to the close proximity of the nucleophile. Subsequently, a conjugation reaction spontaneously takes place between the nucleophile and the electrophile, and leads to an intermolecular covalent linkage. This strategy was first showcased in coiled coil peptides which include a cysteine mutation at a selected position. The short peptide sequence was used for covalent labeling of cell surface receptors. The same strategy was then used to guide the design of a set of protein Lego bricks for covalent assembly of protein complexes of unnatural geometry. We finally made "reactive peptides" for natural adaptor proteins that play significant roles in signal transduction. The peptides were designed to react with a single domain of the multidomain adaptor protein, delivered into the cytosol of neurons, and re-directed the intracellular signal of neuronal migration. The trilogy of protein labeling, assembly, and inhibition of intracellular signals, all through a specific covalent bond, fully demonstrated the generality and versatility of "affinity-guided covalent conjugation" in various applications.

A facile solution phase synthesis of directly ordering monodisperse FePt nanoparticles

The ordered Pt-based intermetallic nanoparticles(NPs)with small size show superior magnetic or catalytic properties,but the synthesis of these NPs still remains a great challenge due to the requirement of high temperature annealing for the formation of the ordered phase,which usually leads to sintering of the NPs.Here,we report a simple approach to directly synthesize monodisperse ordered L1_(0)-FePt NPs with average size 10.7 nm without further annealing or doping the third metal atoms,in which hexadecyltrimethylammonium chloride(CTAC)was found to be the key inducing agent for the thermodynamic growth of the Fe and Pt atoms into the ordered intermetallic structure in the synthetic process.In particular,10.7 nm L1_(0)-FePt NPs synthesized by the proper amount of CTAC show a coercivity of 3.15 kOe and saturation magnetization of 45 emu/g at room temperature.The current CTAC-assisted synthetic strategy makes it possible to deeply understand the formation of the ordered Pt-based intermetallic NP in solution phase synthesis.