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Graphene oxide (GO) exhibits great application in rubber industry due to its unique two-dimensional nanosheet structure, significant specific surface area, good barrier property, and high reactivity. However, different rubbers, such as carboxylated nitrile butadiene rubber (XNBR), natural rubber (NR), and styrene butadiene rubber (SBR), have different interactions with GO, which has great influence on the reinforcement effect of GO to the rubber matrix. In this work, the enhancement mechanism of GO on NR, SBR, and XNBR was studied by combining experiments with molecular dynamics (MD) simulation. The results show that GO/XNBR nanocomposites had the smallest potential energy difference (ΔWa), mean square displacement (MSD), and free volume fraction (FFV), resulting in excellent solvent resistance, and dynamic and mechanical properties. This study provides a new way to explore the macroscopic properties of rubber nanocomposites through molecular-level simulation.

High-throughput computation and machine learning studies are conducted for the rational design of ensembles of alloy catalysts for selective catalytic oxidation of NH3 (NH3-SCO).

High throughput calculation is performed to reveal the ruling laws of catalytic performance and further screen potential alloy catalysts with high activity and selectivity for selective catalytic oxidation of ammonia (NH3-SCO).

Developing large capacity electrode with fast charging capability has always been our goal for high-energy Li-ion batteries. To design a superior electrode, large enough capacity, suitable voltage plateau and good ionic/electronic conductivity need to be taken into account at the same time. Herein, by fusing the semiconductor Ge into nonmetal P, a novel metallic GexP60-x solid solution with wide range tuneable region is proposed, which is proved a kind of Ge-P binary alloy instead of typical ionic/covalent compound. The synthesized GexP60-x is not a metal phophide, which is in contradictory to our conventional view. Attributed from its unique phosphorus-like layered structure, those GexP60-x alloys possess a high conductivity (∼2.4 × 106 S/m). More specially, the Ge-P interaction is not a strong covalent bond like metal phosphides and thereby, the conversion reaction process based on chemical bond breaking in metal phosphides would not take place in those GexP60-x alloys, being replaced by alloying-type mechanism only. Therefore, such GexP60-x alloys are the first ones which can simultaneously exhibit both large capacity (>1800 mAh/g), unexpected high reversibility (ICE>90%) and suitable voltage plateau (∼0.5 V), delivering 770 mAh/g within 15 min with low yet safe voltage for fast-charging battery. This discovery that nonmetallic and semiconductor elements can form conductive alloys based on solid solution chemistry injects fresh blood into high-performanced anode families and offers a new strategy for material design toward advanced fast charging electrodes for energy storage.

Micro structures of viscoelastic materials (VEM) play an important role in their mechanical properties and energy dissipation capacities. This work shows a mathematical modeling of VEMs considering...

The intrinsic carbon defects including pentagons, vacancies and sp3-hybridized carbon have recently been proposed as efficient reactive sites for oxygen reduction reaction (ORR). Nevertheless, it is still a great challenge to controllably introduce the intrinsic defects into carbon materials. Herein, a universal defect-engineering method via vaporized salt is reported to modify the N-doped carbon surface with abundant sp3-hybridized carbon defects. At an elevated temperature, the vaporized sodium chloride is found to selectively modulate the surface structure of carbon material. The obtained carbon-based electrocatalyst delivers an outstanding electrocatalytic ORR property with a half-wave potential (E1/2) of 0.85 V vs. RHE and an excellent performance in zinc air battery (ZAB) test. The analysis of components and structures of surface elements via XANES and XPS reveals that the increasing sp3-hybridized carbon defects, induced by the vaporized-salt modification, are responsible for the enhancement of ORR performance. The theoretical calculations further suggest the sp3 component hybridizes with original sp2 carbon, forming efficient sp2/sp3 hybridized carbon sites towards ORR. Additionally, other halide salts are proved to have the similar effect on promoting ORR activity and this method can expand to other carbon-based materials, suggesting its universality and significance in synthesis of defect-rich carbon-based materials.

Tritium is an important nuclear fuel in fusion reactors and one of the dominant nuclides in the primary coolant in fission reactors. The storage, feeding, control, monitoring, and transport of tritium are important for practical engineering applications. Because of the high mobility of tritium in both fission and fusion nuclear systems and its effect on human body, tritium has received great attention worldwide. The retention and prevention of tritium permeation from primary loop to secondary loop is a common research interest in various reactors. Previous studies indicated that a surface oxide layer is an efficient method to reduce tritium permeation. In this paper, we summarize the effects of various oxide layers on the permeation of hydrogen isotopes in nuclear reactors. The permeation reduction factor for materials used in fusion reactors ranges from 1000 to 100000. The diffusion behavior of tritium in several materials with and without oxide layer is discussed in detail. The oxide layer is more important than intrinsic permeability to prevent tritium permeation. As tritium is the only radioactive source term in the secondary loop of high temperature gas-cooled reactors, we also reviewed the permeation of hydrogen isotopes in the heat exchanger, which is an important issue in nuclear hydrogen production. The present study provides a comprehensive overview of tritium permeation behavior and is expected to promote the development and design of tritium-permeation-proof materials in the future.

A facile colloidal layer-by-layer deposition of amorphous AlOx is applied on the CsPbBr3 perovskite nanocrystals (PNCs). The CsPbBr3 PNCs show improved photoluminescence intensity and excellent wat...

CO oxidation on NiOx-modified Pt nanoparticles (NPs) was investigated by first-principles calculations and microkinetic methods. The binding energies of O2 and CO on NiOx/Pt suggest that CO adsorption is dominant and the CO oxidation mainly follows the Mars–van Krevelen (M–vK) mechanism. It was found that the interfacial O of NiOx/Pt played a key role in the combination of adsorbed CO to O, as well as the O2 dissociation. With a lower O vacancy formation energy, NiOx/Ptedge shows about four orders higher reaction rates than NiOx/Pt(100). Microkinetic analysis suggests that the rate-determining step also depends on the active O at the interface. The calculations highlight the synergetic effect difference of NiOx selectively deposited on the different sites of Pt NPs on the CO oxidation from the atomic reaction mechanism, and throws light on the high activity of CO oxidation on partially covered NiOx/Ptedge nanoparticles.

Highly efficient bifunctional electrocatalysts towards sluggish oxygen reduction and evolution reactions (ORR and OER) are of great significance for cathode catalysis of rechargeable metal–air batteries. Herein, we report a one-pot pyrolysis strategy to construct binary transition metal oxide (TMO) interfaces on a nitrogen doped porous carbon framework (CN) for bifunctional oxygen reaction catalysis. The constructed Fe3O4/Co3O4 interfaces not only help promote the stabilization of Fe2+ ions, but also generate abundant oxygen vacancies on the surface of composite catalysts (Fe3O4/Co3O4-CN), which boost the intrinsic oxygen reaction activity. The Fe3O4/Co3O4-CN catalyst exhibits a bifunctional electrocatalytic performance with a significantly lowered potential difference (ΔE) of 0.68 V between the half-wave potential of the ORR (E1/2) and the potential of the OER at a current density of 10 mA cm−2 (Ej=10), rivaling the best performance of previously reported bifunctional TMO catalysts to the best of our knowledge. The rechargeable Zn–air battery with Fe3O4/Co3O4-CN as the cathode catalyst exhibits superior performance with an energy density of 1045.82 W h kgZn−1 and a peak power density of 105.7 mW cm−2, as well as excellent cycling stability (over 80 h at a current density of 10 mA cm−2), demonstrating our new bifunctional oxygen electrocatalyst as a promising candidate for practical energy storage applications.

Perovskite nanocrystals (NCs) are promising light-emitting materials for next-generation illuminations and displays. The main challenge for practical applications is to achieve high durability. Her...

Electron transport layers (ETLs) are important components of high-performance all-inorganic perovskite nanocrystals light-emitting diodes (PNCs-LED). Herein, atomic layer deposition (ALD) of inorganic ZnO layer is combined to the organic 1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) to form dual ETLs to enhance both the efficiency and stability of PNCs-LED simultaneously. Optimization of ZnO thickness suggested that 10 cycles ALD yields the best performance of the devices. The external quantum efficiency of the device reaches to 7.21% with a low turn-on voltage (2.4 V). Impressively, the dual ETL PNCs-LED realizes maximum

Tritium (3H) has been increasingly researched when assessing the environmental impact of nuclear reactors and other nuclear facilities because it is widely present in nuclear systems and can easily...

The selective encapsulation of noble metal catalysts is a newly developed method to maintain their durability and reactivity. In our work, we have found that AlOx can preferentially encapsulate Pt nanoparticle facets with dimethylaluminum isopropoxide (DMAI) as an ALD precursor. The selectivity originates from the preferential DMAI decomposition mechanism on double hydroxyl sites of the Pt (111) facet, with the subsequent H2O half cycle rapidly removing residual surface intermediates and regenerating the hydroxyls as reaction sites for subsequent cycles. Related microkinetic and experimental results confirm that by the substitution of one methyl in trimethylaluminum (TMA) with an isopropanol radical, DMAI as the precursor can preferentially coat the Pt (111) facets and leave other sites intact through controlling the ALD deposition parameters. The substituent effect in DMAI is also discussed in detail to give guidance to ALD precursor design. Combining theoretical and experimental studies, our work provides for the first time a feasible strategy to achieve selective decoration of AlOx on Pt nanoparticles via ALD.

The Al concentration and distribution have a great influence on the hydrothermal stability of the H-SSZ-13 zeolites in experiments. In this work, first-principles calculations are performed to clarify the decomposition mechanism of an H-SSZ-13 framework with adjacent Al atom pair distribution under hydrothermal conditions. It is found that the adjacent Al atoms have a tendency to occupy the para-sites of the 4-membered rings (4MRs) in the framework. Water molecules are chemisorbed onto the Al atom one by one, and the hydroxylation of the neighboring O atoms induces the breaking of the Al-O bonds, which causes the first dealumination in 4MRs. The other Al atom in the para-site can be easily removed from the framework once the first one is lost. The feasible subsequent dealumination of adjacent Al atoms would break the linker of 6MRs in the framework, which is responsible for the degraded hydrothermal stability. Moreover, the partial substitution of metal ions (such as Na+ and Cu+) for the protons in the framework will greatly stabilize the Al-O bonds and enlarge the energy barrier of para-site Al dealumination, which leads to the improved hydrothermal stability of H-SSZ-13.

Quantum dots (QDs) are promising candidates for the next-generation optical and electronic devices due to the out-standing photoluminance efficiency, tunable bandgap and facile solution synthesis. Nevertheless, the limited optoelectronic performance and poor lifetime of QDs devices hinder their further applications. As a gas-phase surface treatment method, atomic layer deposition (ALD) has shown the potential in QDs surface modification and device construction owing to the atomic-level control and excellent uniformity/conformality. In this perspective, the attempts to utilize ALD techniques in QDs modification to improve the photoluminance efficiency, stability, carrier mobility, as well as interfacial carrier utilization are introduced. ALD proves to be successful in the photoluminance quantum yield (PLQY) enhancement due to the elimination of QDs surface dangling bonds and defects. The QDs stability and devices lifetime are improved greatly through the introduction of ALD barrier layers. Furthermore, the carrier transport is ameliorated efficiently by infilling interstitial spaces during ALD process. Attributed to the ultra-thin and dense coating on the interface, the improvement on optoelectronic performance is achieved. Finally, the challenges of ALD applications in QDs at present and several prospects including ALD process optimization, in-situ characterization and computational simulations are proposed.

Selective atomic layer deposition shows a great perspective on the downscaling manufacturing of nanoelectronics with high precision. The interaction between Mn precursors and Pt terrace, (100), and (111) facets is investigated by density functional theory and microkinetic modeling to reveal the effect of the ligands of the precursors on MnOx selective growth on the Pt facets. MnCl2 and MnCp2 have preferential deposition on the Pt terrace and (100) over (111), while Mn(acac)2 does not show obvious selectivity on the three pristine Pt facets due to the extremely strong adsorption energies. It is found that the adsorption energies of the Mn precursors exhibit size dependence mainly due to the van der Waals interaction. The increase in the number of methyl substituents of Cp-derivate precursors enlarges the decomposition energy barrier of the precursor on (100) due to the steric hindrance, which weakens the selectivity between (111) and (100) facets. It is found that the oxygen groups on these facets accelerate the decomposition of the precursors, which diminishes the selectivity of the precursors on the three Pt facets. While the surface hydroxyl groups significantly weaken the adsorption of Mn(acac)2, it exhibits preferential deposition on hydroxylated Pt (111) among the three facets. Our work highlights the group effect on adsorption, reaction kinetics, and the selective growth of Mn precursors on Pt facets, which provides important guidance to screen precursors to achieve selective deposition of metal oxides on differentiated metal surfaces.

Lead sulfide quantum dots (QDs) photodetectors have received wide attention due to the merits of low-cost manufacturing, tunable bandgap, and the compatibility with flexible substrates. Currently, ...

The very-high-temperature reactor (VHTR) has been included in the conception of the Generation IV nuclear energy system proposed by the United States Department of Energy Nuclear Energy Research Advisory Committee and the Generation IV International Forum. After the Fukushima accident, concern has grown regarding the safety of nuclear power plants. For its inherent safety, superior proliferation resistance, and high thermal efficiency, the VHTR and its prototype, the high-temperature gas-cooled reactor (HTGR), attracted worldwide interest. Tritium exists in the fuel element and graphite reflectors in the core, primary coolant, some liquid and solid wastes, and gaseous effluent of HTGRs. Due to its permeation behavior at high temperatures, tritium is the most important nuclide in the secondary loop of HTGRs. Considering the future application of HTGRs in hydrogen production, tritium will be non-negligible and could be difficult to separate from hydrogen. In addition, the interaction between tritium and graphite is expected to be very strong. The absorption, desorption, and diffusion of tritium at the interface between the primary coolant and graphite are of great interest. Experimental measurements of the diffusion coefficients of tritium and its isotopes do not agree well with theoretical predictions based on the consideration of isotope effects. In this paper, research progress on the permeation, absorption, desorption, and diffusion behaviors of tritium in HTGRs is summarized and discussed. The chemical form of tritium in the primary coolant, and its spectroscopic characteristics, internal structures, and transport behaviors are organized and analyzed. Basic properties related to tritium, such as isotope effect, nuclear spin, radioactivity, etc. are also discussed.

The size and configuration of small Pdn ensembles (monomers, dimers, trimers, and tetramers) is of great importance not only for the fundamental understanding of single-site catalysis design, but also for practical applications such as automotive emission control and fuel cells. In this study, by coupling the competitive gaseous adsorptions and multiple reaction pathways via a state-to-state microkinetic formalism, we reveal CO oxidation mechanisms on small Pd ensembles under realistic experimental conditions. It is found that reaction of O2 with preadsorbed CO on adjacent Pd sites is the dominant pathway at low temperatures (denoted as the preadsorbed CO oxidation pathway, or PCOP). As the temperature increases, different PCOPs dominate CO oxidation. At even higher temperatures, the CO oxidation reaction proceeds primarily via the recombination of dissociated O atoms and CO (denoted as the dissociated O2 pathway, or DO2P). Among different ensembles investigated, the Pd dimer possesses the best low-temperature CO oxidation activity, while the tetramer outperforms other forms at higher temperatures. It is concluded that oxygen adsorption ability is the main factor influencing the reactivity. This work unravels the intrinsic activity of the catalyst on the microscopic scale and shed light on ensemble engineering for maximizing its reactivity.

At low temperature, water can greatly improve the NH3 selective catalytic reduction (SCR) performance of Cu-SAPO-34 under standard reaction conditions. During the SCR process on Cu-CHA catalysts, oxygen (O2) activation over pairs of Cu(NH3)2+ complexes is a crucial step. The concentration of H2O in the reaction atmosphere may affect the local environment of Cu ions and subsequent oxygen activation. In this work, first-principles calculations are used to study the adsorption of NH3 on Cu sites and the detailed reaction paths of O2 activation with or without water in Cu-SAPO-34. NH3 adsorption is generally favored over H2O on Cu ions, yet at low temperature and with partial pressure of water vapor, H2O and NH3 molecules could co-adsorb on the same Cu site from the phase diagram analysis. During the O2 activation process, this kind of behavior will influence the formation of the Cu(NH3)2+ complex and a new kind of Cu(NH3)(H2O)+ complex will form during the reduction process of Cu2+ ions. Compared with O2 activation over pairs of Cu(NH3)2+ complexes, Cu(NH3)2+–Cu(NH3)(H2O)+ complexes change the torsion angle of the Cu–O–O–Cu configuration and decrease the reaction energy barriers of O2 activation in Cu-SAPO-34. Our results shed light on the water mediated NH3 SCR reaction mechanism of Cu-SAPO-34 at the molecular level.

Recent experiments about the selective coating of transition-metal oxide on Pt nanoparticles have aroused great interest in molecular catalysis for the promotion of both activity and stability. In ...

CO oxidation on NiO

Improving the low-temperature activity (below 100 °C) and noble-metal efficiency of automotive exhaust catalysts has been a continuous effort to eliminate cold-start emissions, yet great challenges remain. Here we report a strategy to activate the low-temperature performance of Pt catalysts on Cu-modified CeO2 supports based on redox-coupled atomic layer deposition. The interfacial reducibility and structure of composite catalysts have been precisely tuned by oxide doping and accurate control of Pt size. Cu-modified CeO2-supported Pt sub-nanoclusters demonstrate a remarkable performance with an onset of CO oxidation reactivity below room temperature, which is one order of magnitude more active than atomically-dispersed Pt catalysts. The Cu-O-Ce site with activated lattice oxygen anchors deposited Pt sub-nanoclusters, leading to a moderate CO adsorption strength at the interface that facilitates the low-temperature CO oxidation performance., Improving low-temperature activity and noble-metal efficiency remains a challenge for next generation exhaust catalysts. Here, the authors achieve the activation of subnanometric Pt on Cu-modified CeO2 for low-temperature CO oxidation with an onset below room temperature.

The low efficiency and fast degradation of devices from ink-jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states caused by both anion and cation under-coordinated sites on the quantum dot surface with proper ligands for ink-jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink-jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink-jet printing processing for possible mass production. And the performance from ink-jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry., Designing efficient and scalable quantum dot LEDs meeting industrial requirements remains a challenge. Here, the authors, by leveraging the liquid phase exchange of d-MX2 ligands, present printed quantum dot LEDs with external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours.

OBJECTIVE: Comparative analysis of the reduction effect of the evoked nystagmus in the non-affect side during Dix-Hallpike(D-H) or Roll-test in unilateral posterior semicircular canal benign paroxysmal positional vertigo(PC-BPPV) and PC-BPPV without above evoked nystagmus. METHOD: Retrospective analysis of 210 patients diagnosed with unilateral PC-BPPV by G-Force BPPV CRP system was made. Among them, 18 patients exhibited positive nystagmus only when the non-affected side was stimulated by D-H test(Group A), 30 was evoked only when stimulated by Roll-test(Group B), 26 was evoked when stimulated by both Roll-test and the non-affected side D-H test(Group C), 136 without nystagmus in the above positions(Group D). All the patients were diagnosed by G-Force BPPV and were treated through simulative Epley or Semont CRP. Compare the reduction effect among the groups. RESULT: At the first time, the reduction effect of nystagmus in Group D was superior to those in Group A and Group C(P < 0.05). There was no difference between Group D and Group B(P>0.05). The difference between Group A and Group C was also non-significant(P>0.05). The average CRP times of the four groups(CRP until nystagmus disappeared or no longer alleviated) were 1.44±0.63(Group A), 1.46±0.65(Group B), 1.52±0.87(Group C) and 1.48±0.73(Group D)respectively. There were no statistic difference between four groups(P>0.05). The differences of final reduction effect between groups were the same as those at the first time. CONCLUSION: The first time reduction effect was less effective when nystagmus evoked the non-affect side during D-H test in unilateral PC-BPPV, while it might be irrelevant to the nystagmus evoked only in Roll-test. Although the times of CRP were similar among the groups, the final reduction effect of groups with nystagmus evoked the non-affect side during D-H was poorer.

All-inorganic perovskite quantum dots suffer from poor stability in a humid and heat environment. In this article, CsPbBr3 quantum dots (CsPbBr3 QDs) are stabilized by coating nanoscale alumina on a CsPbBr3 QDs-silica luminescent sphere (CsPbBr3 QDs-SLS) via atomic layer deposition (ALD). Utilizing the intrinsic reactivity differences toward precursors, the surface defect sites of CsPbBr3 QDs are selectively passivated. The inorganic alumina coating layers can effectively reduce the ion migration and crystal deformation of CsPbBr3 QDs. In situ quartz crystal microbalance measurements show that organic ligands remain attached to the CsPbBr3 QDs surface during the ALD coating process. NMR, XPS, and first-principles calculations are performed to reveal the interaction strength between CsPbBr3 QDs-SLS and precursors. The surface passivation of alumina on CsPbBr3 QDs-SLS effectively stabilizes the QDs without reducing the photoluminescent quantum yield.

The lattice inversion modified embedded atom method (LI-MEAM) is an empirical variant of modified embedded atom method (MEAM) by removing many-body screening function and employing lattice inversion method to considerate the contribution to pair interactions and atomic electron densities from further nearest neighbors. LI-MEAM, which has been applied to BCC crystal systems in previous works, has been extended to FCC crystal structure. Parameters have been determined for eight FCC metals (Ag, Al, Au, Cu, Ni, Pb, Pd and Pt). The LI-MEAM model is fitted to elastic constants, structural energy differences, formation energies of vacancy, surface and stacking fault. Particle swarm optimization is adopted as the strategy to adjust the parameters during the optimization. The determined parameters can reproduce the fitting targets quite well. Additional physical properties of the involved metals are predicted and found reasonable agreement with available experimental data and results calculated by second nearest neighbor MEAM (2NN MEAM).

Uniform p-type CuBi2O4 thin film was prepared through a spin coating method on fluorine-doped tin oxide (FTO) coated glass substrate, with a subsequent hypoxic post-annealing process under semi-sealed condition to enhance its photoelectrochemical efficiency for hydrogen evolution reaction. Compared to CuBi2O4 specimen annealed in open-air environment, the semi-sealed annealed CuBi2O4 photocathode presents a remarkable improvement in cathodic photocurrent, from 0.42 mA/cm2 to 0.7 mA/cm2 at 0.25 VRHE. X-ray photoelectron spectroscopy study revealed that the electronic structure of CuBi2O4 film was significantly modified during the post-annealing process and higher carrier concentration was obtained through Mott-Schottky measurement on semi-annealed CuBi2O4. We also demonstrate that the synthesized CuBi2O4 film with a thin overlayer of sputtered TiO2 can retain good stability and efficiency as a photocathode. This work provides insights into the mechanism of the high efficiency CuBi2O4 photocathode achieved from the unique post-annealing treatment.

Using first-principles based microkinetic analysis, we conduct a comprehensive investigation on the NO oxidation process on SmMn2O5 mullite’s active surface under experimentally relevant conditions. The influencing factor for NO oxidation activity is identified and Mars-van Krevelen (MvK) and Eley-Rideal (ER) mechanisms are found to contribute to the high activity of pristine SmMn2O5 mullites in high and low temperature regions, respectively. We further study the activity of surface (Ba/Sr/La) doped SmMn2O5. It is found that surface doping of Ba primarily destabilizes the nitrite (NO∗) species to promote NO oxidation performance via MvK mechanism. Due to the stronger ability of O2 (O2∗) dissociation along the ER route, Sr and La doped mullites are predicted to have greatly enhanced reaction activity in a wide temperature region. Our study gives insight into the NO oxidation ability of pristine and surface doped SmMn2O5 that are beneficial for further optimization of mullite based catalyst performance.

In this work, we demonstrate a synergistic approach to improve the thermoelectric performance of the InSb compound by introducing a replacement reaction of InSb and TiO2 during a hot pressing process. As a consequence of the replacement reaction, TiIn+ point defects, In2O3, stacking faults and InSb–Sb eutectic structures have been introduced into the InSb matrix. Accordingly, the electrical conductivity and the power factor (PF) have been significantly improved due to the electron donating nature of TiIn+ point defects, and the thermal conductivity has also been greatly reduced owing to the extra phonon scattering by dispersed In2O3 nanoparticles and stacking faults. More importantly, the melt of the introduced InSb–Sb eutectic structures plays an important role in filtering the transverse acoustic phonons, causing an abrupt reduction of lattice thermal conductivity at high temperature (753–773 K). Therefore, a relatively high ZT value ∼1.1 at 773 K has been obtained for the 0.1 wt% TiO2 added InSb sample. Moreover, the Vickers hardness of InSb also increases largely (∼210 Hv) deriving from the strengthening effects by introduced point defects and nanoinclusions, which is tougher than many well established mid-temperature TE materials.

Hematite (α-Fe2O3) is a promising photoanode candidate for photoelectrochemical water splitting under visible light irradiation. In-situ Co and ex-situ Sn are co-doped into α-Fe2O3 nanorods to improve the photoelectrochemical response of the photoanode. It is found that Sn mono-doping enhances the photocurrent density to 0.93 mA/cm2 under AM 1.5 G illumination. However, the onset potential of the photocurrent shifts positively by ∼100 mV. By introducing additional Co dopant, the photocurrent density can be further improved to 1.25 mA/cm2 at 1.23 V (vs. RHE), about four folds that of pristine Fe2O3 photoanode. Moreover, the onset potential of the (Co, Sn) co-doped Fe2O3 photoanode exhibits ∼ 140 mV cathodic shift comparing with that of Sn mono-doped one. Electrochemical analysis suggests that the Sn doping mainly contributes to the increased carriers density, while Co doping mostly improves the surface kinetics of oxygen evolution reaction on Fe2O3 nanorods. The cooperation of Co and Sn into Fe2O3 nanorods yields a high incident photon-to-current conversion efficiencies of 23% at 350 nm. Our work provides a facile co-doping method to improve both the photocurrent and onset potential of the Fe2O3 photoanode.

Ferritic steel is a widely used structural material for both nuclear fusion and advanced fission reactors, yet the presence of helium degrades the mechanical properties of materials. Molecular dynamics (MD) simulation is a commonly used approach to study the mechanism of helium effect in iron from the atomic scale. The accuracy and reliability of MD simulations depends critically on the empirical interatomic potentials. In this work, we develop a high-dimensional neural network potential (HDNNP) to the Fe-He system that incorporates an extensive dataset of 5205 atomic configurations from ab-initio electronic structure calculations. The developed potential not only well reproduces the bulk properties of bcc iron, but also predicts the binding properties and relative stabilities of helium clusters accurately in the iron matrix. Overall, the average error of the binding energies predicted by HDNNP is 0.04 eV per atom as compared to 0.18 eV per atom for previously reported empirical potentials (EPs). The present Fe-He HDNNP is used to perform MD simulations of helium migration in the iron matrix and it is found that migration energies of both interstitial and substitutional helium are highly consistent with ab-initio results.

Graphene oxide (GO) with various oxidation degrees were prepared through a modified Hummer’s method by varying the dosage of oxidizing agent. Styrene-butadiene rubber (SBR)/carboxylated acrylonitrile butadiene rubber (XNBR)/GO nanocomposites were fabricated by aqueous-phase mixing of GO colloidal dispersion with SBR latex and a small loading of XNBR latex, followed by co-coagulation. Effects of GO oxidation degree on the morphology, structure, mechanical and thermal properties of nanocomposites were thoroughly investigated. The results showed that the mechanical strength of nanocomposites were enhanced with the increase of oxidation degree of GO. Especially, when the weight ratio of KMnO 4 to graphite was 15/5, the tensile strength, tear strength and thermal conductivity of SBR/XNBR/GO filled with 3 phr (parts per hundred rubber) GO increased by 255.3%, 141.5% and 22.8%, respectively, compared to those of neat SBR/XNBR blend. In addition, the thermal stability and the solvent resistance of the nanocomposites were also improved significantly. This work suggested that GO with higher oxidation degree could effectively improve the properties of SBR/XNBR blend.

In this paper, graphene oxide (GO) with different oxidation degrees were prepared by a modified Hummers' method, and were filled into carboxylated acrylonitrile butadiene rubber (XNBR) by latex co-coagulation method. The impact of oxidation degrees on the structure of GO, the interaction between GO and XNBR, the mechanical properties and thermal conductivity of XNBR nanocomposites were investigated. The results indicated that interfacial interaction between XNBR and GO became stronger with the increase of oxidation degrees of GO due to more oxygen-containing groups forming on the GO sheets and hydrogen bonding in the XNBR/GO nanocomposites, which led to a better dispersion of GO in rubber matrix as well as improved mechanical properties and thermal conductivity of XNBR matrix. Especially, in comparison with those of neat XNBR, the tensile strength, tear strength and thermal conductivity of XNBR/GO nanocomposites with 4 phr (parts per hundred rubber) GO3 increased by 114.6%, 88.5% and 27.2%, respectively.

Tungsten disulfide (WS 2 ), as a representative layered transition metal dichalcogenides (TMDs), is expected as a promising candidate for high-performance NH 3 sensor at room temperature. Unfortunately, the common WS 2 based NH 3 sensors are difficult to recovery at room temperature, which severely limits its application. Hence, how to improve recovery has become an urgent problem to be solved. Herein, we prepare five types of WS 2 nanosheets with different layer numbers from bulk to monolayer, and find that the recovery time of NH 3 gas sensor is rapidly linear shorten as the number of layers decreasing. Through the first-principles calculation of the interaction between NH 3 and WS 2 substance, the different binding energy between ammonia and the surface (−0.179 eV) and interlayer (−0.356 eV) of layered WS 2 , as well as the different electron transfer way, should be responsible for the difficult recovery rate of various WS 2 samples. Therefore, reducing the number of layer of WS 2 is a promising approach to speed up recovery. Based on this conclusion, we successfully prepare a fast recoverable ammonia gas sensor based on single layer WS 2 , which exhibits exciting fast recovery within 271.9 s at room temperature without any condition. Moreover, our work also can act as a reference for other gas detection of TMDs based gas sensor to improve the gas performance at room-temperature.