Methanol steam reforming for hydrogen production driven by an atomically precise Cu catalyst

Plasmon-induced hot-electron transfer from metal nanostructures is being intensely pursed in current photocatalytic research,however it remains elusive whether molecular-like metal clusters with excitonic behavior can be used as light-harvesting materials in solar energy utilization such as photocatalytic methanol steam reforming.In this work,we report an atomically precise Cu_(13)cluster protected by dual ligands of thiolate and phosphine that can be viewed as the assembly of one top Cu atom and three Cu_(4)tetrahedra.The Cu_(13)H_(10)(SR)_(3)(PR’_(3))_(7)(SR=2,4-dichlorobenzenethiol,PR’_(3)=P(4-FC_(6)H_(4))_(3))cluster can give rise to highly efficient light-driven activity for methanol steam reforming toward H_(2)production.

Atomically precise Ag_(30)Pd_(4)nanocluster as efficient polysulfides redox catalyst in Li-S batteries

Regulating the catalyst electronic structure is critical for improving the adsorption and catalytic conversion of lithium polysulfides(LiPSs)in lithium-sulfur batteries(Li-S),yet which has been overlooked in current studies.In this work,structurally defined Ag_(30)Pd_(4)nanoclusters were loaded onto reduced graphene oxide(Ag_(30)Pd_(4)/rGO)as a modification material for polypropylene(PP)separators to elucidate the catalytic activity towards lithium polysulfides and the impact on the electrochemical properties to lithium sulfur batteries.This unique d-πcombination promotes charge transfer,influences overall charge states,and further enhances adsorption energies in potential reaction pathways with lithium polysulfides.Consequently,the Ag_(30)Pd_(4)/rGO/PP modified batteries exhibited an exceptionally low-capacity decay rate of 0.026%per cycle at 1.0C over 1000 stable cycles and 9.75 mAh cm^(-2)excellent performance even with lean electrolyte and high sulfur loading(9.7 mg cm^(-2)).This study paves a path for employing ultrasmall bimetallic nanoclusters to promote the polysulfides redox kinetics hence boosting the lithiumsulfur battery performance.

Emerging Strategies in Enhancing Singlet Oxygen Generation of Nano-Photosensitizers Toward Advanced Phototherapy

The great promise of photodynamic therapy(PDT) has thrusted the rapid progress of developing highly effective photosensitizers(PS) in killing cancerous cells and bacteria. To mitigate the intrinsic limitations of the classical molecular photosensitizers, researchers have been looking into designing new generation of nanomaterial-based photosensitizers(nano-photosensitizers) with better photostability and higher singlet oxygen generation(SOG) efficiency, and ways of enhancing the performance of existing photosensitizers. In this paper, we review the recent development of nano-photosensitizers and nanoplasmonic strategies to enhance the SOG efficiency for better PDT performance. Firstly, we explain the mechanism of reactive oxygen species generation by classical photosensitizers, followed by a brief discussion on the commercially available photosensitizers and their limitations in PDT. We then introduce three types of new generation nanophotosensitizers that can effectively produce singlet oxygen molecules under visible light illumination, i.e., aggregation-induced emission nanodots, metal nanoclusters (< 2 nm), and carbon dots. Different design approaches to synthesize these nano-photosensitizers were also discussed. To further enhance the SOG rate of nano-photosensitizers, plasmonic strategies on using different types of metal nanoparticles in both colloidal and planar metal-PS systems are reviewed. The key parameters that determine the metal-enhanced SOG(ME-SOG) efficiency and their underlined enhancement mechanism are discussed. Lastly, we highlight the future prospects of these nanoengineering strategies, and discuss how the future development in nanobiotechnology and theoretical simulation could accelerate the design of new photosensitizers and ME-SOG systems for highly effective image-guided photodynamic therapy.

Molybdenum Oxynitride Atomic Nanoclusters Bonded in Nanosheets of N-Doped Carbon Hierarchical Microspheres for Efficient Sodium Storage

Transition metal nitrides have attracted considerable attention as great potential anode materials due to their excellent metallic conductivity and high theoretical specific capacity.However,their cycling performance is impeded by their instability caused by the reaction mechanism.Herein,we report the engineering and synthesis of a novel hybrid architecture composed of MoO2.0N0.5 atomic nanoclusters bonded in nanosheets of N-doped carbon hierarchical hollow microspheres(MoO2.0N0.5/NC)as an anode material for sodium-ion batteries.The facile self-templating strategy for the synthesis of MoO2.0N0.5/NC involves chemical polymerization and subsequent one-step calcination treatments.The design is benefi-cial to improve the electrochemical kinetics,buffer the volume variation of electrodes during cycling,and provide more interfacial active sites for sodium uptake.Due to these unique structural and compositional merits,these MoO2.0N0.5/NC exhibits excellent sodium storage performance in terms of superior rate capability and stable long cycle life.The work shows a feasible and effective way to design novel host candidates and solve the long-term cycling stability issues for sodium-ion batteries.

B12N12 Nano-cage as Potential Sensor for NO2 Detection

The NO2 molecule adsorption on B12N12 nano-cage was investigated using density functional theory calculations in terms of adsorption energy, HOMO/LUMO energy gap （Eg） changes, charge transfer, structural deformation, etc. Furthermore, some aspects of stability and properties of B12N12 including calculation of binding electronic and Gibbs free energies, density of states, and molecular electrostatic potential surfaces are investigated. Three possible configurations for NO2 adsorption on the B12N12 nano-cage are energetically found. Interestingly, the results reveals that the Eg of B12N12 cluster is very sensitive to the pres- ence of NO2 molecules as its value reduces from 6.84 eV in free cluster to 3.23 eV in the most stable configuration of NO2/cluster complex. This phenomenon dramatically increases the electrical conductivity of the cluster, suggesting that the B12N12 nano-cluster may be potential sensor for NO2 gaseous molecule detection.

Fabrication of Ni Nanoclusters-Modied Brookite TiO2 Quasi Nanocubes and Its Photocatalytic Hydrogen Evolution Performance

The development of low-cost, earth-abundant and highly-efficient cocatalysts is still important to promote the photocatalytic H2 evolution reaction over semiconductors. Herein, a series of Ni nanoclusters（NCs） modified brookite TiO2 quasi nanocubes（BTN）（marked as Ni/BTN） are fabricated via a chemical reduction process. It is found that the loading content and oxidation state of Ni NCs can significantly influence the optical absorption, photocatalytic activity, and stability of Ni/BTN composites. Among the resultant Ni NCs-loaded products, 0.1%Ni/BTN composite delivers the best H2 evolution activity（156 μmol/h）,which is 4.3 times higher than that of the BTN alone（36 μmol/h）. Furthermore, the Ni NCs with ultrafine size（2 nm） and high dispersity enable shorter charge transfer distance by quickly capturing the photoexcited electrons of BTN, and thus result in the improved activity even though the oxidization of some Ni NCs on BTN is harmful to the activity for H2 evolution due to the much lower electron capturing capability of NiO than metallic Ni.This study not only clarifies that brookite TiO2 would be a promising high-efficient photocatalyst for H2 evolution, but also reveals vital clues for further improving its photocatalytic performance using low-cost Ni-based cocatalyst.

Producing of cinnamyl alcohol from cinnamaldehyde over supported gold nanocatalyst

Chemoselective hydrogenation of unsaturated aldehyde to unsaturated alcohol has attracted growing interests in recent years due to its widespread applications in fine chemicals.However,the hydrogenation of the C=O bond was thermodynamically and kinetically unfavorable over the hydrogenation of the C=C bond.Thus,to obtain the unsaturated alcohol from the unsaturated aldehyde is very difficult in most of the catalytic systems.In this work,ZnAl-hydrotalcite-supported cysteine-capped Au25 nanoclusters were used as the precatalysts for chemoselective hydrogenation of cinnamaldehyde to cinnamyl alcohol.The catalyst showed stable high selectivity(~95%)at prolonged reaction time and complete conversion of the substrate.According to the results of the control experiments,the in-situ DRIFTS of the substrate under high pressure of hydrogen and the 27Al MAS-NMR spectroscopy,we proposed that the difference of the preferential adsorption of the C=O bond to that of the C=C bond was derived from the nature of the support of the gold catalysts.

Odd-membered cyclic hetero-polyoxotitanate nanoclusters with high stability and photocatalytic H_(2) evolution activity

We investigated the hydrolysis of TiⅣ along with naturally abundant AlⅢ ions and reported the formation of a stable and semiconducting nanocluster. Interestingly, this compound exhibits an unusual odd-membered ring structure and also represents the largest Al-containing polyoxotitanium cluster(PTC) observed thus far. The presence of a shell of organic ligands as well as the incorporation of hetero-AlⅢ ions endowed the nanocluster with high air, thermal, and pH stabilities. The present compound exhibited a record photocatalytic hydrogen evolution of 402.88 μmol g–1 h–1 among PTC materials. This work not only paves the way towards stable PTC materials but also provides new insights into the design of novel photocatalysts.

First Principles Study on Encapsulation of Alkali Metals into ZnO Nanocage

Encapsulation of alkali metals （Li, Na, K, and Rb） into Zn12O12 nanocage has been inves- tigated using density functional theory. Encapsulation of Li and Na atoms is found to be thermodynamically favorable at 298 K and 100 kPa, with negative Gibbs free energy change AG of about -130.12 and -68.43 kJ/mol, respectively. By increasing the size of encapsu- lated atom the process become less favorable so that in the cases of K and Rb encapsulations the AG values are positive. The results indicate that the LUMO, Fermi level, and specially HOMO of the cluster are shifted to higher energies so that the HOMO-LUMO gap of the cluster is significantly narrowed in all the cases. After encapsulation of the alkali metals the work function of cluster is decreased due to the shift of the Fermi level to higher energies. Therefore, the emitted electron current density from the Zn12O12 cluster will be increased.

25-原子金纳米球和纳米棒催化性能的比较(英文)

The catalytic properties of two nanocluster catalysts with atomically precisely known structures,icosahedral two-shelled Au25(SC2H4Ph) 18 nanospheres and biicosahedral Au25(PPh3) 10(SC2H4Ph) 5Cl2 nanorods,were compared. Their catalytic performance in the two reactions of the selective oxidation of styrene and chemoselective hydrogenation of α,β-unsaturated benzalacetone was investigated. The catalytic activities of icosahedral Au25(SC2H4Ph) 18 nanospheres were superior to those of the bi-icosahedral Au25(PPh3) 10(SC2H4Ph) 5Cl2 nanorods for both reactions. The better catalytic performance of the Au25(SC2H4Ph) 18 nanospheres can be attributed to their unique core-shell(Au13/Au12) geometric structure that has an open exterior atomic shell and to their electronic structure with an electron-rich Au13 core and an electron-deficient Au12 shell.

Angle-sensitive and fast photovoltage of silver nanocluster embeded ZnO thin films induced by 1.064-μm pulsed laser

Silver nanocluster embedded ZnO composite thin film was observed to have an angle-sensitive and fast photovoltaic effect in the angle range from -90° to 90° , its peak value and the polarity varied regularly with the angle of incidence of the 1.064-μm pulsed Nd：YAG laser radiation onto the ZnO surface. Meanwhile, for each photovoltaic signal, its rising time reached -2 ns with an open-circuit photovoltage of -2 ns full width at half-maximum. This angle-sensitive fast photovoltaic effect is expected to put this composite film a candidate for angle-sensitive and fast photodetector.

A Facile Synthesis of ZnCo2O4 Nanocluster Particles and the Performance as Anode Materials for Lithium Ion Batteries

ZnCo_2O_4 nanocluster particles(NCPs) were prepared through a designed hydrothermal method, with the assistance of a surfactant, sodium dodecyl benzene sulfonate. The crystalline structure and surface morphology of ZnCo_2O_4 were investigated by XRD, XPS, SEM, TEM, and BET analyses. The results of SEM and TEM suggest a clear nanocluster particle structure of cubic ZnCo_2O_4(*100 nm in diameter), which consists of aggregated primary nanoparticles(*10 nm in diameter), is achieved. The electrochemical behavior of synthesized ZnCo_2O_4 NCPs was investigated by galvanostatic discharge/charge measurements and cyclic voltammetry. The ZnCo_2O_4 NCPs exhibit a high reversible capacity of 700 mAh g^(-1) over 100 cycles under a current density of 100 mA g^(-1) with an excellent coulombic efficiency of 98.9% and a considerable cycling stability. This work demonstrates a facile technique designed to synthesize ZnCo_2O_4 NCPs which show great potential as anode materials for lithium ion batteries.

Activation of Transition Metal(Fe,Co and Ni)-Oxide Nanoclusters by Nitrogen Defects in Carbon Nanotube for Selective CO_(2) Reduction Reaction

The electrochemical carbon dioxide reduction reaction(CO_(2)RR),which can produce value-added chemical feedstocks,is a proton-coupled-electron process with sluggish kinetics.Thus,highly efficient,cheap catalysts are urgently required.Transition metal oxides such as CoO_(x),FeO_(x),and NiO_(x)are low-cost,low toxicity,and abundant materials for a wide range of electrochemical reactions,but are almost inert for CO_(2)RR.Here,we report for the first time that nitrogen doped carbon nanotubes(N-CNT)have a surprising activation effect on the activity and selectivity of transition metal-oxide(MO_(x)where M=Fe,Ni,and Co)nanoclusters for CO_(2)RR.MO_(x)supported on N-CNT,MO_(x)/N-CNT,achieves a CO yield of 2.6–2.8 mmol cm−2 min−1 at an overpotential of−0.55 V,which is two orders of magnitude higher than MO_(x)supported on acid treated CNTs(MO_(x)/O-CNT)and four times higher than pristine N-CNT.The faraday efficiency for electrochemical CO_(2)-to-CO conversion is as high as 90.3%at overpotential of 0.44 V.Both in-situ XAS measurements and DFT calculations disclose that MO_(x)nanoclusters can be hydrated in CO_(2)saturated KHCO_(3),and the N defects of N-CNT effectively stabilize these metal hydroxyl species under carbon dioxide reduction reaction conditions,which can split the water molecules and provide local protons to inhibit the poisoning of active sites under carbon dioxide reduction reaction conditions.

Recent Advances in Organic-inorganic Hybrid Photoresists

Photoresists are radiation-sensitive materials used for forming patterns to build up IC devices.To date,most photoresists have been based on organic polymers,which have been dominating the semiconductor industries over the past few decades.It is obvious that extreme ultraviolet(EUV)lithography has become the next-generation lithography technology.The development of comprehensive performance EUV resist is one of the most critical issues.However,organic polymeric photoresists are difficult to meet the harsh requirements of EUV lithography.Pure inorganic photoresists such as metal salts,hydrogen silsesquioxane(HSQ)are expected for EUV lithography due to their high resistance and high resolution.But the low sensitivity makes them not suitable for high volume manufacturing(HVM).Organic-inorganic hybrid photoresists,containing both organic and inorganic components,are regarded as one of the most promising EUV resists.They combine both merits of organic and inorganic materials and have significant advantages in machinability,etching resistance,EUV absorption,and chemical/thermal stability.Organic-inorganic hybrid photoresists are considered as ideal materials for realizing industrialgrade patterns below 10 nm.This review mainly focuses on the development of organic-inorganic hybrid photoresists over the past decade.

Stabilization of cubic ordering of zirconium dioxide nanoclusters on silicon with laser ablation

Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.

Response Characteristics of Strain Sensors Based on Closely Spaced Nanocluster Films with Controlled Coverage

Flexible strain sensor devices were fabricated by depositing Pd nanoclusters on PET membranes patterned with interdigital electrodes. The sensors responded to the deformation of the PET membranes with the conductance changes of the nanocluster films and were characterized by both high gauge factor and wide detection range. The response characteristics of the strain sensors were found to depend strongly on the nanocluster coverage, which was attributed to the percolative nature of the electron transport in the closely spaced nanocluster arrays. By controlling the nanocluster deposition process, a strain sensor composed of nanocluster arrays with a coverage close to the effective percolation threshold was fabricated. The sensor device showed a linear response with a stable gauge factor of 55 for the applied strains from the lower detection limit up to 0.3%. At higher applied strains, a gauge factor as high as 200 was shown. The nanocluster films also demonstrated the ability to response to large deformations up to 8% applied strain, with an extremely high gauge factor of 3500.

Protein Templated Au-CuO Bimetallic Nanoclusters toward Neutral Glucose Sensing

In this study,the application of bovine serum albumin(BSA)as a carrier to glucose-sensitive materials for the detection of glucose was proposed.Au-Cu O bimetallic nanoclusters(Au-Cu O/BSA)were prepared using BSA as a template,the new sensing material(Au-Cu O/BSA/MWCNTs)was synthesized by mixing with multi-walled carbon nanotubes(MWCNT)and applied to non-enzymatic electrochemical sensors to detect glucose stably and effectively under neutral condition.The scanning electron microscopy was used to investigate the morphology of the synthesized nanocomposite.The electrochemical properties of the sensor were studied by cyclic voltammetry.Glucose detection experiments show that Au-Cu O/BSA/MWCNTs/Au electrode has good glucose detection ability,stability,accuracy,repeatability,and high selectivity in neutral environment.Unlike existing glucose-sensitive materials,due to the use of BSA,the composite material is firmly fixed to the electrode surface without a Nafion solution,which reduces the current blocking effect on the modified electrode.The composite materials can be effectively preserved for extremely long periods,higher than 80%activity is maintained at room temperature in a closed environment for 3 to 4 months,due to the special effects of BSA.In addition,the feasibility of using BSA in glucose-sensitive materials is confirmed.

Amorphous Fe Nanoclusters Embedded inside Balloon-Like N-Doped Hollow Carbon for Efficient Electrocatalytic Oxygen Reduction

Rational designs of electrocatalytic active sites and architectures are of great importance to develop cost-efficient non-noble metal electrocatalysts towards efficient oxygen reduction reaction(ORR)for high-performance energy conversion and storage devices.In this work,active amorphous Fe-based nanoclusters(Fe NC)are elaborately embedded at the inner surface of balloonlike N-doped hollow carbon(Fe NC/Csphere)as an efficient ORR electrocatalyst with an ultrathin wall of about 10 nm.When evaluated for electrochemical performance,Fe NC/Csphere exhibits decent ORR activity with a diffusionlimited current density of~5.0 mA/cm^(2)and a half-wave potential of~0.81 V in alkaline solution,which is comparable with commercial Pt/C and superior to Fe nanoparticles supported on carbon sheet(Fe NP/C sheet)counterpart.The electrochemical analyses combined with electronic structure characterizations reveal that robust Fe-N interactions in amorphous Fe nanoclusters are helpful for the adsorption of surface oxygen-relative species,and the strong support effect of N-doped hollow carbon is benefitial for accelerating the interfacial electron transfer,which jointly contributes to improve ORR kinetics for Fe NC/Csphere.

Ordered mesoporous carbon spheres assisted Ru nanoclusters/RuO_(2) with redistribution of charge density for efficient CO_(2) methanation in a novel H2/CO_(2)fuel cell

Efficiently reducing carbon dioxide(CO_(2))into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO_(2)ncentration.In prior work,we described a unique H/CO_(2)fuel cell driven by low-valued waste heat,which not only CO_(2)nverts CO_(2)to methane(CH_(4))but also outputs electrical energy,yet the CO_(2)reduction rate needs to be urgently improved.Here,a novel Ru-RuOcatalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuOinto ultrasmall Ru clusters(~1 nm),in which heteroatom-doped carbon spheres as a matrix with excellent CO_(2)nductivity and abundant pores can not only easily CO_(2)nfine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru CO_(2)mplex and the mass transport.CO_(2)mpared to pure RuOnanoparticles supported on carbon spheres,our CO_(2)mposite catalyst boosts the CO_(2) nversion rate by more than 5-fold,reaching a value of 382.7μmol gcat.h-1at 170℃.Moreover,a decent output power density of 2.92 W mwas obtained from this H2/CO_(2)fuel cell using Ru-RuOembedded carbon spheres as a cathode catalyst.The Ru-RuOheterostructure can modify the adsorption energy of CO_(2)and induce the redistribution of charge density,thus boosting CO_(2)reduction significantly.This work not only offers an efficient catalyst for this novel H_(2)/CO_(2)fuel cell but also presents a facile method to prepare Ru nanoclusters.

On Some Applications of Nanoparticles Synthesized in the Gas Phase by Magnetron Discharges

For the seventies, scientists focused their researches to find techniques to produce high quality films. One of the ideas, for example, was to generate an ionized cluster beam (ICB) formed by inert gas condensation (IGC) from evaporation of material. This method generates non-agglomerated nanoparticles to be deposited onto any substrate. However, the synthesis of spherical and well-dispersed nanoparticles remains, today, a major technological issue. Several trials have been performed with magnetron sputtering that has the advantage of producing very pure atomic vapour from a wide variety of solid materials or composites, and therefore in this configuration offers the possibility to synthesize nanoparticles in a gaz phase with potential numerous applications. In this paper, we describe several results of our laboratory and we show how it is possible to synthesize non-agglomerated nanoparticles with a narrow size distribution in the nm range. Detailed examples of Ag, TiO2, Au, Y, C, Co and Fe are given. We illustrate their current use in applications including catalyst to produce aligned Multi-Wall Carbon Nanotubes, seeding layer to promote anatase TiO2 crystallisation for photocatalytic material, superhydrophobic material and nanoparticle for nanomedecine.