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Photoelectrochemical (PEC) technology has been proved a promising approach to solve the problems of energy shortages and environmental pollution damages. It can convert unlimited solar energy resources into energy forms needed by mankind. The development of highly efficient photoanodes is a key step in realizing the large-scale practical application of PEC systems. However, the development of PEC photoanodes has been severely hindered by the issues of easy recombination of photo-generated charge carriers, low photon-to-electron conversion efficiency, poor photo-corrosion resistance, and low catalytic activity. Therefore, constructing high-performance and stable photoanodes is an urgent research field to promote the progress of PEC technology. The atomically thin molybdenum disulfide (AT-MoS2) with unique physical and chemical properties has been widely applied in the fabrication of PEC photoanodes. The AT-MoS2 based photoanodes have exhibited excellent PEC performance, which providing promising candidates for ideal PEC application. Here, we summarize the fundamental natures of MoS2 and present the research efforts in the preparation of AT-MoS2 based photoanodes. Strategies for the fabrication of high-efficient AT-MoS2 based photoanodes are emphasized to provide guidelines to advance emerging PEC photoanodes. Besides, perspectives for the development of more efficient AT-MoS2 based photoanodes are proposed.

Ion-irradiated FeCr alloys are useful for understanding and predicting neutron damage in the structural steels of future nuclear reactors. Previous studies have largely focused on the structure of irradiation induced defects, probed by transmission electron microscopy (TEM), as well as changes in mechanical properties. Across these studies, a wide range of irradiation conditions has been employed on samples with different processing histories, which complicates the analysis of the relationship between defect structures and material properties. Furthermore, key properties, such as irradiation-induced changes in thermal transport and lattice strain, are little explored. Here we present a systematic study of Fe3Cr, Fe5Cr and Fe10Cr binary alloys implanted with 20 MeV Fe3+ ions to nominal doses of 0.01 dpa and 0.1 dpa at room temperature. Nanoindentation, transient grating spectroscopy (TGS) and X-ray micro-beam Laue diffraction were used to study the changes in hardness, thermal diffusivity and strain in the material as a function of damage and Cr content. Our results suggest that Cr leads to an increased retention of irradiation-induced defects, causing substantial changes in hardness and lattice strain. However, thermal diffusivity varies little with increasing damage and instead degrades significantly with increasing Cr content in the material. We find significant lattice strains even in samples exposed to a nominal displacement damage of 0.01 dpa. The defect density predicted from the lattice strain measurements is significantly higher than that observed in previous TEM studies, suggesting that TEM may not fully capture the irradiation-induced defect population. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

It is well-known that steels always oxidize faster in the environments containing water vapour than in dry oxygen. Due to the difficulties in obtaining necessary experimental scale of observations, the mechanisms responsible for the steam-accelerated oxidation are still unclear. Through a combination of multiscale characterization techniques, the surface oxide film formed on an Fe-17Cr-9Ni stainless steel after exposure to high-temperature steam has been studied in detail. The characterization results obtained in this study reveal that the inner oxide layer actually consists of two phases Fe-Ni austenite and FeCr2O4 oxide, which formed due to internal oxidation. The classic internal oxidation model underestimates the thickness of the inner oxide layer by one order of magnitude. This difference can be explained by the existence of fast diffusion channels in the inner oxide layer. This study provides direct evidence of a high density of nanopores in the oxide phase of the internal oxide layer, which can act as fast-diffusion channels if interconnected, and proposes their mechanisms of formation, a consequence of water dissociation-induced protons promoting the formation, migration, and clustering of both cation and anion vacancies.

Furfural and 5-hydroxymethylfurfural (HMF) have been identified as promising bio-platform furans that have a wide range of potential applications as biofuels, bioplastics, and biochemicals. Furfural and HMF are typically synthesized from the substrates of C5 sugars and C6 sugars, respectively. Furfural can also be produced from C6 sugars, which is technically more challenging owing to the higher energy requirement for carbon&ndash, carbon bond cleavage. In this study, the simultaneous production of furfural and HMF from glucose was conducted over different binary catalyst systems of Br&oslash, nsted acids and Lewis acids using &gamma, valerolactone (GVL) as the solvent. A promising performance was achieved by a SnSO4-H2SO4 coupling catalyst, with an optimized furfural yield of 42% and an HMF yield of 34% at 443 K in GVL. In addition, a kinetics study was performed in order to understand the mechanism of the simultaneous formation of furfural and HMF from glucose at different temperatures and GVL/water ratios. The results showed that the ratio of furfural to HMF production rate at different temperatures (433 to 463 K) or GVL/water ratios (90 to 80%) was constant close to 1, suggesting that the production of furfural and HMF might follow similar reaction pathways. Finally, the reaction pathway of glucose conversion to furfural and HMF was proposed based on the experimental and kinetics studies.

A coupled electrochemical system (CES) for the electroreduction of CO2 to formate (ERCF) and simultaneous degradation of organic pollutants is a promising approach for CO2 conversion. Cathode material is a critical component of CES. However, the poor performance and complexity of synthesis limit its real application. Here, we report a Bi-based binder-free gas diffusion electrode (EBGDE) as a high-performance cathode for CES. The EBGDE was fabricated via direct electrodeposition of Bi nanosheets on a gas diffusion layer. By optimizing the deposition time of Bi nanosheets, a good Faraday efficiency (91.46 ± 6.58%) and formate production rate (1849.96 ± 127.69 μmol m−2 s−1) were obtained. Simultaneously, the methyl orange decolorization efficiency and chemical oxygen demand removal efficiency reached 100% and 55.25 ± 6.87%, respectively. This performance towards ERCF is better than recently reported ERCF electrodes. It probably results from the excellent performance of associated Bi-nanosheets catalysts, a high electroactive surface area, as well as fast electron transfer in the EBGDE. This work offers design rules to fabricate high-performance cathode materials for CES in industrial applications.

In-situ heavy ion (1 MeV Kr2+) irradiation was carried out to investigate the evolution of irradiation induced lattice defects at room temperature and the stability of β-Zr under irradiation at temperatures ranging from 150 to 350 °C. It was found that the irradiation induced defects started to appear at a dose between 0.5 dpa and 0.75 dpa, which is relatively high compared to the case for α-Zr. The number density of dislocation loops increased exponentially with fluence, with an exponential index ∼3.52. The statistical results show that the electron beam with which in-situ observation was carried out had an influence on the size of the dislocation loops. The g·b analysis shows that dislocation loops with Burgers vector ½ 1 ¯ 11> and are both present in the sample after irradiation to 1.5 dpa. ω phase particles precipitate out during irradiation at 250 and 350 °C, as a result of the combination of the thermal treatment and irradiation enhanced concentration of point defects.

This work aims to degrade a typical antibiotic Norfloxacin (NOR) in saline water with a novel green carbon black based Ti/SnO2-Sb electrochemical catalysis system (TSSC), with Ti/SnO2-Sb as anode (TSSA) and a novel carbon black air diffusion electrode as cathode (CBAC). An electrochemical system with TSSA and a platinum carbon (Pt/C) cathode was used as control (TSSP). The removal ratio, degradation condition and the biodegradability were evaluated, the degradation pathway and mechanism were investigated. The result showed an efficient removal performance in both TSSC and TSSP systems. The removal ratio dropped with the lower current densities and higher initial pollutant loading. A considerable better removal performance was found in TSSC system, compared to that in TSSP system, when the low current density and saline concentration were applied. Meanwhile, 25.7% and 23.0% of COD removal ratios were obtained in TSSP and TSSC systems, respectively, in a short reaction time (25 min) and a very slight current density (0.18 mA cm−2). However, the TSSC showed a much more significant improvement of NOR biodegradability than that in TSSP system, indicating a considerable potential of TSSC system for both individual application and synergistic working with traditional bio-degradation system for refractory antibiotics treatment.

A direct comparison between the microstructural evolution during the annealing of a TEM thin foil (thickness ~100 nm) and the bulk material of Zr-2.5Nb-0.5Cu alloy is presented. The results indicate that at an intermediate temperature, (550 °C), diffusion-controlled phenomena such as boundary migration and precipitate coarsening are retarded in the thin foil due to a thickness effect. At high temperature, (815 °C), the chain of transformations a) Widmanstatten → α + β, b) precipitate dissolution in the matrix and c) precipitation at the β phase is observed in the bulk material. In the thin foil, however, sufficient activation energy for the first transformation is not provided; consequently, growth of the initial precipitates with a smaller energy barrier progresses. Possible transformation retardation mechanisms in thin foils are discussed.

A series of solid electrolyte cells with La0.8Sr0.2MnO3 (LSM)-Ce0.8Sm0.2O1.9 (SDC) composite cathodes was fabricated for the electrochemical decomposition of nitric oxide (NO). The LSM and SDC powders were synthesized by a combined EDTA-citrate method. Thermogravimetry with differential scanning calorimetry, X-ray diffraction analysis, scanning and transmission electron microscope with electron diffraction were performed to characterize the synthesized powders. The NO conversions and power consumptions of the solid electrolyte cells with the cathodes sintered at 900–1200 °C were evaluated. The electrochemical properties, microstructures, and crystalline phases of the cathodes were further studied by electrochemical impedance spectrum, scanning electron microscope and X-ray diffraction, respectively. The NO conversions and electrochemical performances of the cells at different operating temperature were also investigated. It was concluded that the LSM and SDC powders calcined at 900 °C both showed good crystal structures with high purity. The cell with the cathode sintered at 1100 °C had the highest NO conversion of 65.4% and the lowest power consumption of 0.2024 W under 80 mA applied current. The total polarization resistances of the cells with the cathodes sintered at 900–1200 °C were 63.32, 41.75, 38.11 and 97.57 Ω cm2 in 800 ppm NO, respectively. The cathode sintered at 900 °C had an incompact structure and connected with the electrolyte loosely, thereby impeding the NO adsorption on the cathode surface and the transfer of O2− from three phase boundary (TPB) to electrolyte. The excess sintering temperature of 1200 °C resulted in a dense structure of cathode and La2Zr2O7 formation at the interface between the cathode and electrolyte, thereby leading to a poor NO decomposition performance. This study also found that the NO conversion increased with the rise of operating temperature and 600 °C was not suitable for operation because of the electrode degradation caused by the overvoltage.

NOx is a significant atmospheric pollutant triggering haze weather. The existing DeNOx technology has drawbacks of needing additional reducing agent and high working temperature. In order to overcome those defects, a novel La0.6Sr0.4Fe0.8Mn0.2O3 (LSFM)-modified gas diffusion electrode (GDE) was prepared to establish an in-situ electrochemical DeNOx process. The DeNOx efficiency was enhanced by increasing Nafion and polytetrafluoroethylene (PTFE) content in the GDE within an appropriate range. Nafion created the proton transport pathway of electrolyte-Nafion-three phase interfaces (TPIs) and PTFE improved the hydrophobic gas channels. The highest DeNOx efficiency of 71.1% was obtained with inlet NOx of 1000 ppm under ambient temperature (25 °C) when the mass ratio of LSFM:Nafion:PTFE was 1:0.117:0.23. In the electrochemical DeNOx process, i) NOx was absorbed by the gas diffusion layer and then transferred to the catalyst layer through the hydrophobic channels; ii) NOx was electrochemically decomposed to N2 and O2− under the catalysis of LSFM; iii) O2− was transformed to OH− on the TPIs by combining with H+ and oxidized to O2 in the anode. Simultaneously N2 was released. Its advantages of no reducing agent, mild operating condition and high energy-efficiency indicate great potential for practical application.

In this paper, 40 MeV Zr ion irradiation of Zr-2.5Nb pressure tube alloy was carried out, delivering a damage layer 6.5 μm deep. Uniaxial micropillar compression experiments along the tube axial (AD) and transverse directions (TD) were conducted. Irradiation was found to alter the deformation mechanisms and to increase the yield strength more in the AD oriented pillars than TD pillars for irradiation up to 0.6 dpa. This anisotropy in response is discussed in terms of the limitations of the micropillar compression method and the different deformation mechanisms which are activated in each orientation. The anisotropic hardening effect of -type dislocation loops on prismatic , basal , and pyramidal slip systems is also discussed. The micropillar compression results were also compared with nanoindentation results conducted on the same material.

Coupling of nano-indentation and crystal plasticity finite element (CPFE) simulations is widely used to quantitatively probe the small-scale mechanical behaviour of materials. Earlier studies showed that CPFE can successfully reproduce the load-displacement curves and surface morphology for different crystal orientations. Here, we report the orientation dependence of residual lattice strain patterns and dislocation structures in tungsten. For orientations with one or more Burgers vectors close to parallel to the sample surface, dislocation movement and residual lattice strains are confined to long, narrow channels. CPFE is unable to reproduce this behaviour, and our analysis reveals the responsible underlying mechanisms.

Using transient grating spectroscopy (TGS) we measure the thermal diffusivity of tungsten exposed to different levels of 20 MeV self-ion irradiation. Damage as low as 3.2 x 10^-4 displacements per atom (dpa) causes a measurable reduction in thermal diffusivity. Doses of 0.1 dpa and above, up to 10 dpa, give a degradation of around 55% from the pristine value at room temperature. Using a kinetic theory model, the density of irradiation-induced point defects is estimated based on the measured changes in thermal diffusivity as a function of dose. These predictions are compared with point defect and dislocation loop densities observed in transmission electron microscopy (TEM). Molecular dynamics (MD) predictions are combined with the TEM observations to estimate the density of point defects associated with defect clusters too small to be probed by TEM. When these "invisible" defects are accounted for, the total point defect density agrees well with that estimated from TGS for a range of doses spanning 3 orders of magnitude. Kinetic theory modelling is also used to estimate the thermal diffusivity degradation expected due to TEM-visible and invisible defects. Finely distributed invisible defects appear to play a much more important role in the thermal diffusivity reduction than larger TEM-visible dislocation loops. This work demonstrates the capability of TGS, in conjunction with kinetic theory models, to provide rapid, quantitative insight into defect densities and property evolution in irradiated materials., The following article has been revised and submitted to Acta Materialia. After it is published, it will be found at https://www.journals.elsevier.com/acta-materialia

Developing a comprehensive understanding of the modification of material properties by neutron irradiation is important for the design of future fission and fusion power reactors. Self-ion implantation is commonly used to mimic neutron irradiation damage, however an interesting question concerns the effect of ion energy on the resulting damage structures. The reduction in the thickness of the implanted layer as the implantation energy is reduced results in the significant quandary: Does one attempt to match the primary knock-on atom energy produced during neutron irradiation or implant at a much higher energy, such that a thicker damage layer is produced? Here we address this question by measuring the full strain tensor for two ion implantation energies, 2 MeV and 20 MeV in self-ion implanted tungsten, a critical material for the first wall and divertor of fusion reactors. A comparison of 2 MeV and 20 MeV implanted samples is shown to result in similar lattice swelling. Multi-reflection Bragg coherent diffractive imaging (MBCDI) shows that implantation induced strain is in fact heterogeneous at the nanoscale, suggesting that there is a non-uniform distribution of defects, an observation that is not fully captured by micro-beam Laue diffraction. At the surface, MBCDI and high-resolution electron back-scattered diffraction (HR-EBSD) strain measurements agree quite well in terms of this clustering/non-uniformity of the strain distribution. However, MBCDI reveals that the heterogeneity at greater depths in the sample is much larger than at the surface. This combination of techniques provides a powerful method for detailed investigation of the microstructural damage caused by ion bombardment, and more generally of strain related phenomena in microvolumes that are inaccessible via any other technique., Comment: Please refer to the supplementary information and movies SM1-3 for data visualisation

The microstructure of the surface oxide film formed on an Fe-9Cr Ferritic-Martensitic (F-M) steel after exposure to deaerated high-temperature steam at 600°C for 100 h has been analyzed in detail by advanced characterization techniques. The surface oxide film has been revealed to have a triplex structure, including an outer oxide layer, an inner oxide layer, and an internal oxide layer. Although the outer and inner oxide layers are continuous, the internal oxide layer has been proved to consist of interconnected metallic and chromite phases, which is a typical feature of internal oxidation. The formation mechanisms of each layer have been discussed, finding that, contrary to what the available space model suggests, an external oxidation is not the controlling oxidation mechanism of F-M steels in high-temperature steam. The higher resolution used in this study confirms that the controlling mechanism is internal oxidation.

Displacive transformations have been widely reported in metals, alloys and ceramics, but rarely reported to be important in the aqueous corrosion of alloys. We report here our analysis of the formation of the hexagonal-ZrO suboxide during the aqueous corrosion of α-Zr alloys and propose this to be a paraequilibrium displacive transformation with the rate controlled by oxygen diffusion. Two orientation relationships were identified between α-Zr and hexagonal-ZrO, ( 0002 ) α − Z r ∥ ( 1 ¯ 011 ) h − Z r O and [ 2 ¯ 110 ] α − Z r ∥ [ 10 1 ¯ 2 ] h − Z r O or ( 0002 ) α − Z r ∥ ( 22 4 ¯ 1 ¯ ) h − Z r O and [ 2 ¯ 110 ] α − Z r ∥ [ 1 1 ¯ 01 ] h − Z r O , with the first one more commonly observed. No specific orientation relationships between either hexagonal-ZrO and monoclinic-ZrO2 or α-Zr and monoclinic-ZrO2 were identified, which suggests that the formation of often-reported bulk oxide texture during aqueous corrosion is not related directly to the texture of the metallic substrate. These results provide a guideline for understanding the mechanisms of crystallographic evolution during oxide growth on commercial zirconium alloys, and also demonstrate the capability of transmission Kikuchi diffraction to investigate orientation relationships in nano-scale materials.

In-situ electrocatalytic flue gas desulfurization (FGD) using a carbon black (CB)-based gas diffusion electrode (GDE) is efficient with no secondary pollution. However, higher desulfurization efficiency and energy conservation are demanded. In this work, CB-based GDEs were modified with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate)-multi-walled carbon nanotubes (PEDOT: PSS-MWCNTs) for H2O2 production from two-electron oxygen reduction reaction (2e-ORR) during in-situ FGD. The results showed that the GDE modified with 100 mg 5% PEDOT: PSS-MWCNTs obtained the highest desulfurization efficiency (100.0%) and the lowest energy consumption (1.07 kW h kg−1), as 2e-ORR efficiency is improved from balancing ORR catalysis, pore structure, hydrophilicity, conductivity of the GDE, and the noncovalent interaction between MWCNTs and PEDOT: PSS. While excess PEDOT: PSS in the PEDOT: PSS-MWCNTs composite would cause reduced total pore area and porosity and excessive hydrophily which is harmful to O2 transfer for the GDE, hindering the 2e-ORR and desulfurization. This compact in-situ FGD system has advantages in desulfurization efficiency, energy consumption and durability, showing great potential in future industrial application.

Cr-coatings processed for different times were synthesized on the surface of AISI 5140 steel by double glow plasma surface alloying (DGPSA). The microstructures, microchemistry and phases of the coating were characterized by backscattering electron imaging (BSEI), energy dispersive spectrometry (EDS), and X-ray diffraction (XRD). The results show that the Cr-coating prepared by DGPSA consists of three layers: a deposited-layer, a diffusion-layer and an affected-layer. With increasing DGPSA processing time, the relative thickness, microstructure and phase composition of the three layers vary greatly. The deposited-layer is mainly composed of pure-Cr, the diffusion-layer consists of Cr-Fe solid solution (Cr-Fe SS) and/or Cr-Fe intermetallic compound (Cr-Fe IMs), while the affected-layer is composed of high-Cr pearlite. After depositing Cr by DGPSA, the corrosion potential is improved and the corrosion current is reduced. Subsequent annealing not only promotes the precipitation of the multiple carbides particles within the pure-Cr coating, but also promotes the transformation of Cr-Fe IMs into Cr-Fe SS. However, these changes have little effect on the hardness and corrosion resistance of the coatings. Keywords: Double glow plasma surface alloying, Chromizing, Hardness, Corrosion resistance, Annealing

Coupled electrochemical system (CES) for electroreduction of CO2 and simultaneous degradation of organic pollutants is a promising CO2 conversion method. However, its performance is severely restrained by insufficient reactants and low electroactive surface areas on the cathode material. Here, a series of novel Sn-based carbon nanotubes (CNTs)/carbon black hybrid gas diffusion electrodes (CNTx/ESGDEs) were fabricated and used as cathodes to enhance the performance of the CES with methyl orange (MO) as a target pollutant. The results show that at an appropriate content of CNTs, the CNTx/ESGDEs offered increased total pore area, porosity, electroactive surface area, and decreased charge transfer resistances. The current density, Faraday efficiency, formic acid production rate, MO removal efficiency, and COD removal efficiency were improved by 140%, 92%, 404%, 76%, and 131%, respectively, at 40 wt% CNTs probably due to enhancement in the electroactive surface area as well as reactant transfer. This study benefits the large-scale applications of CES.

Using bibliometric analysis combined with information visualization analysis, this paper aims at investigating the global characteristics and trends of research on ceramic membranes. According to the 3697 publications from 1998 to 2016 in Science Citation Index Expended, this study was conducted from five major aspects, including basic growth trends analysis, countries/ territories and institutions analysis, categories and journals analysis, keywords analysis, and citation bursts detection. This study revealed positive growth trends of the research on ceramic membranes. The most productive countries and institutions were both from Peoples R China, and the collaborations among countries and institutions were frequent worldwide. The result of categories analysis revealed that the major discipline groups of the research on ceramic membranes were distributed in chemistry, physics, material, and application. Water resource, energy, environmental science and food engineering were the main application fields of ceramic membranes according to the journals analysis. Furthermore, three keyword clusters were identified, indicating that the main research directions of the research on ceramic membranes included membrane filtration, oxygen permeation and the fabrication of ceramic membranes. Finally, the top 20 citation bursts with the maximum burst strength were detected, indicating that the research on oxygen separation and water treatment has been flourishing in recent years.

Converting austenite to martensite is a very effective and low-cost strategy for steel strengthening, but it results in a significant loss of ductility. In this study, we propose a novel method which simultaneously strengthens and toughens austenitic steels by introducing a gradient of martensite phase. We find that a gradient of deformation-induced martensite (α′-M) particles, with a volume fraction increasing from core to surface can be obtained in cylindrical AISI 304 stainless steel (304 SS) rods by applying free-end-torsion (FET). We compared the microstructures and tensile properties of gradient-structured 304 SS prepared by unidirectional-torsion (UT) and cyclic forward/reverse torsion (CFRT). It appears that piled-up dislocations formed near the core region during FET processing play a key role in the subsequent tensile deformation, and control the strain-hardening ability of the FET treated samples. The gradient α′-M enhances the strength of the surface layer and improves the tensile properties of the FET treated samples as a whole. Compared to UT, CFRT is more effective in inducing martensitic transformation, and enhances the gradient distribution of the α′-M. These findings provide a pathway for developing high strength and good ductility steels and other alloyed metals via gradient distributed second phase particles. Keywords: Gradient-structured metals, Gradient martensite, Torsion, Deformation-induced martensite, Mechanical properties

This article presents a novel quasi in-situ analysis, which allowed for examining the same microstructural area before and after irradiation, in two distinct facilities. One facility is used for the irradiation, and one for the energy dispersive X-ray spectroscopy (EDX) in a transmission electron microscope (TEM). The material studied is an austenitic oxide dispersion strengthened (ODS) stainless steel, modeled after commercial grade 310 L (25Cr 20Ni 2Mo-0.02C-0.4N-0.35Y2O3-0.5Ti-bal.Fe), which is synthesized from a powder metallurgy fabrication route using hot isostatic pressing. ODS materials are suitable for applications in: structural, highly corrosive, nuclear, and electromagnetic field environments. In fact, new generation fusion systems represent all four of these demands at the same time. The 310-ODS material is irradiated to ∼1.5dpa at 520OC with 1 MeV Kr2+ 7.5 × 1014 ions cm−2 (∼1.25 × 10−3 dpa/s). Quasi in-situ EDX line scans are presented, focusing on the interactions of: Fe, Cr, Ni, Y, Ti, and O. The examined particles are two Ti-rich structures, which present themselves as non-stoichiometric oxides (>200 nm) embedded within the iron matrix. The Y/Ti at% ratios in both observed particles decreased slightly from 0.34 ± 0.07 and 0.28 ± 0.04, to 0.26 ± 0.08 and 0.20 ± 0.06 respectively, suggesting a dissolution mechanism has initiated under this irradiation condition. It is often a question of dissolution vs. amorphization in these materials. Included is a detailed discussion of these two mechanisms as a function of temperature, fluence, and irradiating energy, with contrast to the current literature. Furthermore, attached is a data-in-brief (DiB), which includes the EDX spectrum and raw data captured from the experiment.

A novel kind of Z-scheme ternary heterojunctions phosphate-doped BiVO4/graphene quantum dots/P-doped g-C3N4 (BVP/GQDs/PCN) were fabricated for the visible light degradation of norfloxacin (NOR), a typical antibiotic. Compared with binary type-II heterojunction phosphate-doped BiVO4/PCN (BVP/PCN), Z-scheme BVP/GQDs/PCN exhibited promoted interfacial charge transfer efficiency and broadened visible light response range, endowing them with excellent photodegradation activity and mineralization ability in NOR degradation. A high NOR degradation rate of 86.3% with a removal rate of total organic carbon (TOC) of 55.8% can be achieved over BVP/GQDs/PCN for 120 min visible light irradiation, which is an excellent performance compared with ever reported similar photocatalysts. In particular, because of the enhanced redox ability of photogenerated charges and the generation of multiple active species (eg. OH and O2−) over Z-scheme photocatalytic system, the accumulation of highly toxic degradation intermediates was greatly inhibited, and a better detoxication performance was obtained compared to PCN and BVP/PCN. This work may shed light on the inhibition of highly toxic degradation intermediates of antibiotics by regulating the charge transfer mechanism, photocatalytic active species, and the degradation pathway of antibiotics.

In this study, induction heating chromizing (IHC) and box-type furnace heating chromizing (BFHC) were conducted on commercial AISI 5140 steels, respectively. Microstructure, microhardness and wear resistance of the chromized samples were characterized. The results show that the IHC samples have thicker Cr coating layer and stronger interface bond due to pre-compressive stress among the packed powders. Three kinds of microstructures including alloyed cementite (AC-layer), fine pearlite zone (FP-zone) and carbon-poor zone (CP-zone) are formed near the interface in the IHC samples. The main reason given for this is that different contents of Cr and C have different effects on pearlite phase and morphology. The IHC sample shows better wear properties due to its stronger interface bonding strength than that of the BFHC sample. The formation mechanism of CP-zone and its influences on microhardness and wear resistance are also discussed.

Graphene-doped (

In this paper, a dual phase Zr-Sn-Nb-Mb alloy was studied with TEM after thermal treatment and high-temperature tensile deformation. Plate and pressure tube material, manufactured through different processing routes, were used in this study. The overall average concentrations of Mo and Nb in the β phase are higher in the pressure tube than in the plate. It was revealed that these concentrations have significant effects on the subsequent stability of the β and ω phases as well as on the precipitation behavior of the α phase from the β phase. That is, the higher the concentrations, the more stable the β and ω phases are, and hence there is a reduced tendency for precipitation of α phase. Aging treatments cause the transformation of athermal ω to isothermal ω, as expected. The most striking finding is the product of the decomposition of the isothermal ω particles during aging treatment is determined as not being α phase, even though the structure of it is, as-yet, not fully determined. The non-uniform morphology of the β grains in the plate material provides us a unique opportunity to investigate the effects of morphology on the aging response of the β phase. It was found that thin β filaments suppress the precipitation of isothermal ω particles but enhance the precipitation of α phase at α/β interfaces. The effect of the Burgers orientation relationship between α and β grains on the precipitation of the α phase at the α/β interface is discussed. Applied high-temperature stress/strain has been found to enhance the decomposition of isothermal ω phase but suppress α precipitation inside the β grains. The suppression of α precipitation by applied stress/strain is discussed in terms of the ω assisted α precipitation. Implications of these findings for the in-service application of the alloy are discussed.

The thermodynamically equilibrium precipitates that form in the Zr-Excel alloy after long-term (2500 h) annealing at 550 °C were investigated with transmission electron microscopy and X-ray diffraction techniques. The equilibrium precipitates were found to be a form of cubic Zr(Mo,Nb,Fe) 2 with about 26.5 at.% Mo substituted by Nb. Differential scanning calorimetry (DSC) heating curves show that the phase transformation sequence is αZr + Zr(Mo,Nb,Fe) 2 → αZr + Zr(Mo,Nb,Fe) 2 + βZr → αZr + βZr → βZr upon heating the long-term annealing alloy. With the heating rate of 10 °C/min, the αZr is found to transform into βZr at 530 °C, and Zr(Mo,Nb,Fe) 2 completely dissolves at a temperature higher than 771 °C, while the αZr disappears at 969 °C.

In this study, hot-extruded copper rods were subjected to free-end-torsion and subsequent annealing. The microstructures and mechanical properties of the deformed samples and annealed samples were investigated. The results show that torsion can introduce gradient lamellar dislocation substructures (LDS) into the copper rods, suggesting a gradient distribution of stored energy from core to surface. Different degrees of recrystallization were formed in the same torsional rod after recrystallization annealing due to such gradient stored energy. Annealing can change the microstructure inversely from deformed gradient into annealed gradient distribution via fully recrystallization in the surface layer and incomplete recrystallization in the middle layer. Therefore, gradient structured copper rods with soft core and hard shell or hard core and soft shell could be obtained by torsion or the combination of torsion and subsequent annealing, respectively. The tensile yield strength of such gradient structured rods has a linear relationship with the volume fraction of hard and soft regions no matter where the hard region is located, core or surface. The incomplete recrystallization mechanisms of gradient structured copper rods induced by torsion were also discussed.

This study reportsin situobservations of the formation of the δ′-ZrO phase, occurring during the annealing of transmission electron microscopy (TEM) thin foils of both pure Zr and a Zr–Sn–Nb–Mo alloy at 973 K in a transmission electron microsope. The lattice parameters of δ′-ZrO were measured and determined to be similar to those of the ω-Zr phase. The orientation relationship between the δ′-ZrO and α-Zr phases has been identified as either {(11 \overline{2}0)}_{\rm ZrO}//{(0002)}_{\alpha} and {[0002]}_{\rm ZrO}//{[11 \overline{2}0]}_{\alpha} or {(\overline{1}011)}_{\rm ZrO}//{(0002)}_{\alpha} and {[01{\overline 1}1]_{{\rm{ZrO}}}}//{[11{\overline 2}0]_\alpha} depending on the orientation of the α grain relative to the TEM thin-foil normal. The nucleation and growth of δ′-ZrO were dynamically observed. This study suggests a new and convenient way to study oxidation mechanisms in Zr alloys and provides a deeper understanding of the properties of the newly reported δ′-ZrO. Since δ′-ZrO has a Zr sublattice which is identical to that of ω-Zr, the orientation relationships between the α and δ′-ZrO phases may also shed light on the orientation relations existing between α- and ω-Zr, and hence α- and ω-Ti.

The thermodynamically equilibrium state was achieved in a Zr-Sn-Nb-Mo alloy by long-term annealing at an intermediate temperature. The fcc intermetallic Zr(Mo, Nb) 2 enriched with Fe was observed at the equilibrium state. In-situ 1 MeV Kr 2+ heavy ion irradiation was performed in a TEM to study the stability of the intermetallic particles under irradiation and the effects of the intermetallic particle on the evolution of type dislocation loops at different temperatures from 80 to 550 °C. Chemi-STEM elemental maps were made at the same particles before and after irradiation up to 10 dpa. It was found that no elemental redistribution occurs at 200 °C and below. Selective depletion of Fe was observed from some precipitates under irradiation at higher temperatures. No change in the morphology of particles and no evidence showing a crystalline to amorphous transformation were observed at all irradiation temperatures. The formation of type dislocation loops was observed under irradiation at 80 and 200 °C, but not at 450 and 550 °C. The loops were non-uniformly distributed; a localized high density of type dislocation loops were observed near the second phase particles; we suggest that loop nucleation is favored as a result of the stress induced by the particles, rather than by elemental redistribution. The stability of the second phase particles and the formation of the type loops under heavy ion irradiation are discussed.

With the aim to remove NO x from the lean-burn engine exhaust, a novel in-situ electrochemical device was designed using carbon black-based gas diffusion electrode (GDE) as cathode. Taking advantage of the excessive O 2 from the exhaust, in-situ electro-generation of H 2 O 2 from oxygen reduction reaction (ORR) under catalysis of the GDE could oxidize NO x to NO 3 − . The highest NO x removal efficiency was 77.7% for 1000 ppm NO x with energy consumption of 1.327 W cm −2 cm −3 . The electrochemical NO x removal pathway was proposed that, as NO and O 2 were adsorbed on different sites in the catalyst layer (CL), electro-generated H 2 O 2 attacked the C―N adsorption bonds mostly in the nitro compounds to oxidize adsorbed NO to NO 3 − , while NO 2 was directly oxidized by the produced H 2 O 2 in the electrolyte. The NO x removal efficiency is mainly controlled by the NO adsorption rate as well as the H 2 O 2 oxidation rate, and the former is the dominant factor. This in-situ electrochemical NO x removal system exhibited properties of energy-saving, low–cost and environmental compatibility, indicating great potential for industrial application.

A feasible approach was developed for the co-production of 5-hydroxymethylfurfural (5-HMF) and furfural from corncob via a new porous polytriphenylamine–SO3H (SPTPA) solid acid catalyst in lactone solvents. XRD, SEM, XPS, N2 adsorption–desorption, elemental analysis, TG–DTA, acid–base titration and FTIR spectroscopy techniques were used to characterize the catalyst. This study demonstrates and optimizes the catalytic performance of SPTPA and solvent selection. SPTPA was found to exhibit superior catalytic ability in γ-valerolactone (GVL). Under the optimum reaction conditions, simultaneously encouraging yields of furfural (73.9%) and 5-HMF (32.3%) were achieved at 448 K. The main advantages of this process include reasonable yields of both 5-HMF and furfural in the same reaction system, practical simplicity for the raw biomass utilization, and the use of a safe and environmentally benign solvent.

Furfural is industrially produced from hemicellulose-derived pentoses, the production of furfural from hexoses is technologically challenging. In the present work, modified versions of zeolite beta containing iron, tin, or zirconium site were prepared from H-Beta via ion-exchanged route. XRD, TEM, SEM, N2 adsorption–desorption, ICP-AES and pyridine FTIR spectroscopy techniques were used to characterize these materials. All these catalysts possess high specific surface areas and adequate acidities, with both Bronsted and Lewis acid sites. The prepared modified beta zeolites were then used as catalysts for converting C6 carbohydrates to furfural in γ-valerolactone (GVL). The reactions were quite selective for furfural, with furfural as the predominant product and 5-HMF as the main by-product. Promising results were achieved for Sn-Beta, which could optimize the furfural yield from glucose up to 69.2% at 453 K for 33 min. The improved activity and selectivity of the catalysts were correlated with their suitable textural and acidic properties. Moreover, the results revealed that reaction solvent played a key role in mediating sugars conversion and product species. Finally, the stability and regeneration of the catalyst were also evaluated.

Electrochemical flue gas desulfurization technology has received much attention in recent years due to its good performance and environmental friendliness. However, there are still demands in energy efficiency enhancement and cost reduction. In this study, carbon black-based gas diffusion electrodes (GDEs) are used to produce H 2 O 2 via oxygen reduction reaction (ORR) for in-situ oxidation of SO 2 to SO 4 2 − in an electrolysis system. The effect of multi-walled carbon nanotubes (MWCNTs) and activated carbon (AC) as minor additive in the catalytic layers of GDEs is investigated. The results show that the MWCNTs play a positive role depending on its electrocatalysis for 2e-ORR, electron-bridge action and mesopore structure, giving the highest H 2 O 2 production (1002.4 mg L −1 ), SO 2 removal efficiency (98.0%) and reaction kinetics (0.52 mM min −1 ) and the lowest energy consumption (1.7 kW h kg −1 ) among the three GDEs. While the AC is adverse to the SO 2 removal due to its excessive porous structure and catalysis on H 2 O 2 reduction. The GDEs may be poisoned by SO 3 2− or SO 4 2− adsorption on active sites as sudden power failure and long-time running, but it can be restored by conducting only ORR, indicating great potential in industrial application.

Novel ternary nanocomposites with facet coupled structure were synthesized by using modified g-C 3 N 4 , TiO 2 nanosheets and nano-ZnO. Nanosheet/nanosheet heterojunction structure was investigated by TEM, XPS and XRD. FT–IR and Nitrogen adsorption were illustrated for chemical/physical structure analyses. Solution of p -Toluenesulfonic acid ( p -TSA) was chosen as target pollutant for visible light photodegradation and the excellent removal efficiency was achieved by this structurally modified g-C 3 N 4 /TiO 2 /ZnO hybrid. The visible light absorption improvement and quantum efficiency enhancement, which were testified by UV–vis DRS, PL and p -TSA photodegradation measurements, due to the facet coupled structure and appropriate quantity of modified g-C 3 N 4 in the nanocomposites.

Synchrotron X-ray diffraction, scanning electron microscopy, and transmission electron microscope bright field and high angle annular dark field were employed to investigate the microstructure and precipitates of a Zr-2.5Nb-0.5Cu alloy wire, with potential application as a spacer in the CANDU® reactor design. Results show that three types of microstructure co-exist in the alloy: Widmanstatten structure, α-Zr grains without precipitates and α-Zr grains with precipitates. In the meantime, three types of second phase particles are detected: β-Nb, Zr2Cu and Zr2Fe, which have different distributions within the microstructure. The β-Nb precipitates are observed to be extensively distributed among the α plate boundaries and twin interfaces in the Widmanstatten structure, whereas the Zr2Cu and Zr2Fe precipitates are only found in the α plate boundaries. The orientation relations of the Zr2Cu precipitates with respect to the α-Zr and β-Nb are found to be ( 013 ) Zr 2 Cu / / ( 0001 ) α ( 013 ) Zr 2 Cu / / ( 0001 ) α , [ 0 3 ¯ 1 ] Zr 2 Cu / / [ 1 ¯ 100 ] α and ( 013 ) Zr 2 Cu / / ( 011 ) β − Nb , [ 0 3 ¯ 1 ] Zr 2 Cu / / [ 2 ¯ 1 ¯ 1 ] β − Nb respectively.

With aim to develop an efficient heterogeneous metal-free cathodic electrochemical advance oxidation process (CEAOP) for persistent organic pollutants (POPs) removal from wastewater under mild conditions, electrochemically reduced graphene oxide (ERGO)-modified gas diffusion electrode (GDE) was prepared for oxygen-containing radicals production via electrochemical oxygen reduction reaction (ORR). A detailed physical characterization was carried out by SEM, Raman spectroscopy, XRD and XPS. The electrocatalytic behavior for ORR was investigated by electrochemical measurements and electrolysis experiments under constant current density. Bisphenol A (BPA) of 20 mg L −1 was used as a model of POPs to evaluate the performance of the CEAOP with ERGO-modified GDE. The results showed that the defects concentration and electrochemical active sites of the ERGO was increased as the reduction time (30 min, 60 min and 120 min), leading to different catalysis on ORR. O 2 generation via one-electron ORR was found under the electrocatalysis of ERGO (60 min and 120 min), contributing to a complete degradation of BPA within 20 min and a mineralization current efficiency (MCE) of 74.60%. An alternative metal-free CEAOP independent of Fenton reaction was established based on ERGO-modified GDE for POPs removal from wastewater under mild conditions.

Tungsten is the main candidate material for plasma-facing armour components in future fusion reactors. In service, bombardment with energetic neutrons will create collision cascades that leave behind lattice defects. Helium, injected from the plasma and produced by transmutation, strongly interacts with these defects, modifying their behaviour and retention. Helium-ion-implantation provides an effective tool for examining helium-defect interactions and their effect on the properties of tungsten armour. We use nano-indentation to probe the mechanical properties of the shallow helium-ion-implanted layer. Comparison of spherical indents in unimplanted and helium-implanted regions of the same single crystal shows a large increase in hardness and substantial pile-up in the implanted material. The complex lattice distortions beneath indents are probed non-destructively using 3D-resolved synchrotron X-ray micro-diffraction. Reduced lattice rotations and indentation-induced residual strains in the ion-implanted material indicate a more confined plastic zone. This is confirmed by HR-EBSD and TEM observations. Together our results suggest that dislocation motion is initially obstructed by helium-induced defects. The obstacle strength of these defects is reduced by the passage of dislocations, leading to a strain-softening and slip channel formation. A constitutive law for 3D crystal plasticity finite element simulations is developed based on this hypothesis. Simulations of the indentation process successfully capture the helium-implantation induced changes in deformation behaviour observed in experiments. Importantly, the effects we observe are markedly different from previous observations for self-ion-implanted tungsten, highlighting that the exact nature of the implantation damage plays a critical role in determining mechanical property change.

We observe large-scale surface terraces in tungsten oxidised at high temperature and in high vacuum. Their formation is highly dependent on crystal orientation, with only {111} grains showing prominent terraces. Terrace facets are aligned with {100} crystallographic planes, leading to an increase in total surface energy, making a diffusion-driven formation mechanism unlikely. Instead we hypothesize that preferential oxidation of {100} crystal planes controls terrace formation. Grain height profiles after oxidation and the morphology of samples heat treated with limited oxygen supply are consistent with this hypothesis. Our observations have important implications for the use of tungsten in extreme environments.

The real antibiotic industrial wastewater with the characteristics of complex compositions, biological toxic, and degradation-resistant, is still biologically toxic to the ecosystem and human health even if the discharge standards have been met after treatment by traditional methods. Therefore, the biological harmless treatment of real antibiotic industrial wastewater is a valuable and meaningful research field. For the first time, a novel Ti/SnO2-Sb anode/air diffusion cathode/UV dual photo-electro catalysis coupling system (T-A-PE) for real antibiotic industrial wastewater treatment was investigated. Non-significant degradation was found in raw wastewater with high TOC = 2.61 × 103 mg·L−1. However, the increasing TOC removal with more dilution times indicated adaptability of T-A-PE system with lower organic matter loading. The highest 95.6% removal of TOC was obtained at 120 min, with 7.06 mA·cm−2 of current density and 200 dilution times. The high mineralization efficiency of T-A-PE system surpassed those of pure photo and electro catalysis combined, suggesting a significant synergistic effect between photo and electro catalysis. Neutral condition and current density = 7.06 mA·cm−2 are prior for pollutants mineralization, while acidic/alkaline conditions and unproper current density may cause faster side reactions. The GC–MS results demonstrated that the number of pollutant category dropped from 26 to 6 after treatment, with the concentrations of remained ones also remarkably decreased. The acute toxicity analysis using a luminescent bacteria method indicated that the treated wastewater by T-A-PE system was biological harmless.

A co-electrolysis system of CO2 and organic pollutants (CES) is promising for CO2 conversion and organic pollutant removal. However, it is still challenging to achieve the simultaneous efficient CO2 conversion and organic pollutant removal by tuning the electrode potential. Herein, we report a novel electrolysis mode for the CES. The anode potential was controlled by a potentiostat, while the cathode potential was controlled by changing the cathode surface area. By controlling the anode potential at 1.8 V and the cathode surface area at 0.1 cm2 (i.e., the anode/cathode surface area ratio was 10), both the anode and cathode potential values in the CES could be maintained to where CO2 reduction to formate and organic pollutant (p-nitrophenol in this study) removal were favored. The efficiencies for formate production and p-nitrophenol removal were almost the same as their optimal values in the individual electrochemical processes. Moreover, compared to the conventional electrolysis mode, our proposed electrolysis mode increased the current efficiency 1.25–1.41 times. Overall, this study clearly demonstrated that our proposed electrolysis mode is a feasible strategy to obtain simultaneous efficient formate production and organic pollutant removal in the CES, which can accelerate the use of the CES in industrial applications.

Sn-based gas diffusion electrodes (GDEs) are promising for electroreduction of CO2 to formate (ERCF) as they can alleviate CO2 mass transfer limitations. However, current electrodes suffer from large catalyst size or poor electron and/or ion connections. This limits ERCF performance. Here, we report a Sn-based GDE (IE-Sn) for ERCF fabricated via deposition of Sn nanoparticles onto a gas diffusion layer by using an impregnation-electroreduction method. The characterization results showed that the IE-Sn has small Sn catalyst size (16 nm) and excellent electronic and ionic transfer properties. Moreover, the faradaic efficiency (87.12 ± 4.28%) and partial current density for formate (62.79 ± 5.33 mA cm−2) obtained from the IE-Sn is 2.45-fold and 4.86-fold, respectively, of those of the traditional electrode. This ERCF performance is one of the best among recently reported Sn-based GDEs under similar conditions. Further analyses reveal that the enhanced ERCF performance of the IE-Sn is linked to the large electroactive surface area, enhanced adsorption capacity and chemisorption ability of CO2, better stabilization of CO2.– intermediate, and excellent ion/electron transfer. This study offers design rules to fabricate high-performance electrode materials for ERCF.

Predicting the dramatic changes in mechanical and physical properties caused by irradiation damage is key for the design of future nuclear fission and fusion reactors. Self-ion irradiation provides an attractive tool for mimicking the effects of neutron irradiation. However, the damaged layer of self-ion implanted samples is only a few microns thick, making it difficult to estimate macroscopic properties. Here we address this challenge using a combination of experimental and modelling techniques. We concentrate on self-ion-implanted tungsten, the frontrunner for fusion reactor armour components and a prototypical bcc material. To capture dose-dependent evolution of properties, we experimentally characterise samples with damage levels from 0.01 to 1 dpa. Spherical nano-indentation of grains shows hardness increasing up to a dose of 0.032 dpa, beyond which it saturates. Atomic force microscopy (AFM) measurements show pile-up increasing up to the same dose, beyond which large pile-up and slip-steps are seen. Based on these observations we develop a simple crystal plasticity finite element (CPFE) model for the irradiated material. It captures irradiation-induced hardening followed by strain-softening through the interaction of irradiation-induced-defects and gliding dislocations. The shear resistance of irradiation-induced-defects is physically-based, estimated from transmission electron microscopy (TEM) observations of similarly irradiated samples. Nano-indentation of pristine tungsten and implanted tungsten of doses 0.01, 0.1, 0.32 and 1 dpa is simulated. Only two model parameters are fitted to the experimental results of the 0.01 dpa sample and are kept unchanged for all other doses. The peak indentation load, indent surface profiles and damage saturation predicted by the CPFE model closely match our experimental observations. Predicted lattice distortions and dislocation distributions around indents agree well with corresponding measurements from high-resolution electron backscatter diffraction (HR-EBSD). Finally, the CPFE model is used to predict the macroscopic stress-strain response of similarly irradiated bulk tungsten material. This macroscopic information is the key input required for design of fusion armour components.

Flue gas desulfurization (FGD) based on electro-chemical technologies is efficient and environment-friendly. However, the low dissolved oxygen concentration, insufficient active sites, and high cost of electrode materials are still three bottlenecks needed to be solved. In this work, a series of novel carbon black-based gas diffusion electrodes (GDEs) doped with different multi-walled carbon nanotube (MWCNT) amounts were developed to generate H2O2 via oxygen reduction reaction (ORR) for in situ FGD. The influence of current density and electrolyte concentration for desulfurization performance was investigated. As a result, the GDEs doped with 100 mg MWCNTs gave the highest desulfurization efficiency (98.0%) and the lowest energy consumption (1.7 kW h kg−1) owing to its good balance on the porous structure, conductivity, and ORR activity. An appropriate current density (3.54 mA cm−2) and electrolyte concentration (50 mM) are conducive to the two-electron ORR and desulfurization. While the excessive values would cause some side reactions and the occupations of active sites by the SO4 2−. This compact system exhibits advantages of high desulfurization efficiency and low-energy consumption with no secondary pollution, providing an alternative way for in situ FGD in industrial application.

Neutron diffraction line profile analysis (DLPA) and transmission electron microscopy were used to characterize the components of the bimodal microstructure of Zr-Excel (Zr–3.5Sn–0.8Mo–0.8Nb), a nuclear structural material. The dual microstructure, consisting of equiaxed primary grains and martensitic domains both having hexagonal close-packed (h.c.p.) α crystal structure, forms when the as-received Zr-Excel alloy is heat treated at a high temperature and subsequently quenched,i.e. is solution treated. Because both microstructure components have the same crystal structure the reflections from the two components overlap significantly. The article presents how the multi-phase analysis capability of modern DLPA methods can be used to model the measured neutron diffraction patterns as the sum of two sub-patterns corresponding to the components of such a bimodal microstructure, which can be found in many hexagonal alloys relevant for industrial applications. The results show that the large equiaxed primary h.c.p. α grains have a highly correlated low-density dislocation structure and large sub-grains (∼300 nm), while the large martensitic domains have a randomly arranged very high density dislocation structure and sub-grains the size of ∼30 nm. The significantly different defect structures of the primary and martensitic phases manifest as large differences in the hardness and ductility of the individual components. As a result of this duality of the mechanical properties, solution-treated Zr-Excel materials can be considered as analogous to metal matrix composites where a softer ductile matrix contains a harder brittle reinforcing phase.

Flow regimes of particles are predicted by means of discrete element method (DEM) in a horizontal rotating ellipsoidal drum (RED) at different rotation speeds and flattening. The macroscopic behavior of the particle flow is produced in a horizontal RED at specified rotation speed, and compared to the motion of particles in the horizontal rotating cylinder drums (RCD). Simulations indicate that there are two different flow regimes in one round with the rotating angles of the horizontal RED. The particle bed became more dilated with the increase of rotation speed. The evolution of resulting contact forces between particles and drum walls is predicted in the horizontal RED at different rotation speeds and flattening. Simulated mixing index indicates that the mixing of particles is improved at the low rotation speed and the segregation of particles is enhanced at the high rotation speed in the horizontal RED. The translational granular temperature and con temperature are calculated from simulated instantaneous velocity and displacement of particles. The predicted configurational and translational granular temperatures increase with the increase of rotation speeds and flattening in the horizontal RED. The rate of energy dissipation based on the generalized granular temperature is increased with the increase of rotation speeds in the horizontal RED.

Zr-Excel alloy (Zr-3.5Sn-0.8Nb-0.8Mo, wt.%) has been proposed as a candidate material of pressure tubes in the CANDU-SCWR design. It is a dual-phase alloy containing primary hcp α-Zr and metastable bcc β-Zr. Metastable hexagonal ω-Zr phase could form in β-Zr as a result of aging during the processing of the tube. A synchrotron X-ray study was employed to study the lattice properties of the metastable phases in as-received Zr-Excel pressure tube material. In situ heavy ion (1 MeV Kr 2+ ) irradiations were carried out at 200 °C and 450 °C to emulate the stability of the metastable phase under a reactor environment. Quantitative Chemi-STEM EDS analysis was conducted on both un-irradiated and irradiated samples to investigate alloying element redistribution induced by heavy ion irradiation. It was found that no decomposition of β-Zr was observed under irradiation at both 200 °C and 450 °C. However, ω-Zr particles experienced shape changes and shrinkage associated with enrichment of Fe at the β/ω interface during 200 °C irradiation but not at 450 °C. There is a noticeable increase in the level of Fe in the α matrix after irradiation at both 200 °C and 450 °C. The concentrations of Nb, Mo and Fe are increased in the ω phase but decreased in the β phase at 200 °C. The stability of metastable phases under heavy ion irradiation associated with elemental redistribution is discussed.

The influences of pre-torsion deformation on microstructure and tensile strength of commercial as-extruded Cu rods with cylindrical shape have been investigated in this study by twisting the rods to different numbers of revolutions. The results indicated that the pre-torsion can significantly enhance the tensile yield strength of the as-extruded Cu rods without changing their shape and size. The increase in tensile yield strength is mainly due to the gradient lamellar dislocation substructures (LDS) embedded in elongated fiber grains introduced by pre-torsion pure shear deformation. Keywords: Copper, Torsion, Deformation properties, Gradient microstructure

With a view to balancing light absorption and redox capabilities, narrowing band gap and adjusting bandgap structure, a novel tubular Bi12O17ClxBr2−x (BCxB2−x) solid solution structure was fabricated using a facile polyvinylpyrrolidone K30 assisted solvothermal strategy. Photocatalytic degradation experiments were conducted under visible light, utilizing tetrachlorobiphenyl A (TCBPA) as the target pollutant. Within 120 min of irradiation, the Bi12O17ClBr (BCB) solid solution nanotubes exhibited approximately 92.8 % TCBPA degradation efficiency. Moreover, the active radical trapping experiments and electron spin resonance measurements show that superoxide and hydroxyl radicals play important roles. Importantly, BCB solid solution photocatalysts have a stable crystal structure and good recycling ability after five cycles of photodegradation. The work presents a feasible synthesis method for the design of solid solution materials and introduction of oxygen vacancies to improve visible-light photocatalytic ability for the treatment of environmentally refractory organic pollutants.