Boron modification has been validated as an efficient strategy for boosting Fe-based Fenton catalysis. Nevertheless, it remains challenging to synchronously achieve boron doping and heterostructure modulation while steering ROS generation pathways. Herein, a novel B-FeS2 nanocatalyst with dual modification was synthesized via a wet mechanochemical-thermal method. Boron modification constructs a FeS2/boron sheet heterostructure that suppresses oxidation and agglomeration, while introducing electron-donating BB and FeB bonds. The B-FeS2 Fenton system achieves >90% BPA removal across a wide pH range (3-10), exhibits Kobs and mineralization efficiency 1.4 and 1.89 times higher than those of bare FeS2, respectively, and maintains stable performance over five cycles and 12 h continuous operation. Mechanistic studies reveal that B doping upshifts the Fe d-band center, which correlates with an altered H2O2 cleavage pathway characterized by enhanced ·O2- generation alongside sustained ·OH production, suggesting a possible shift in the relative contribution of homolytic versus heterolytic pathways. The generated ·O2- directly degrades BPA and sustains Fe2+/Fe3+ cycling via the Haber-Weiss reaction, a synergy particularly advantageous under alkaline or anoxic conditions. This work demonstrates that B modification serves as an effective electronic modulator for FeS2, providing mechanistic insights into designing iron-based Fenton system with tailored ROS pathways.

Titanium alloys have been extensively employed in the aerospace industry, and their service performance is largely governed by high-temperature low-cycle fatigue damage. However, investigations into the fatigue behavior of TC25 titanium alloy subjected to corrosion in a marine atmospheric environment remain limited. In this study, high-temperature low-cycle fatigue tests were conducted on TC25 titanium alloy before and after corrosion. It was found that, after corrosion, the proportion of the structural failure stage increased by approximately 10%. The corrosion pits on the surface led to local stress concentration, resulting in an increase in the number of fatigue crack sources and an acceleration of the fatigue crack growth rate, thus reducing the fatigue life of the material. These findings provide important theoretical and experimental support for the application of TC25 titanium alloy in marine environments.

The corrosion of DD32 alloy in a marine atmospheric environment was investigated through accelerated corrosion tests. The corrosion morphology and products of alloy were discussed by the SEM, XRD, and XPS characterization. Under marine atmospheric corrosion, corrosion pits formed on the alloy surface. As time progressed, these pits deepened and coalesced into elongated pits, resulting in a reduction of the alloy's corrosion resistance. The main corrosion products on the surface were in terms of Al2O3, Cr2O3, NiO, and NiCr2O4. In addition, the electrochemical behavior of DD32 alloy before and after corrosion was further analyzed with the polarization curve and the impedance spectrum. The results indicated that the corrosion resistance of the corroded alloy decreased and the thickness of the passive film decreased from 0.65 nm before corrosion to 0.38 nm. Under marine atmospheric environmental conditions, the corrosion of alloy was affected by active oxygen, and the corrosion process occurred cyclically, reducing the alloy's corrosion resistance. This study provides guidance for the application of nickel - based single crystal alloy in marine atmospheric environments.

The influence of the accelerated marine atmospheric environment on the corrosion and mechanical properties of the K4648 alloy was investigated with electrochemical and creep tests in this work. The results show that the K4648 alloy is covered by Al2O3, Cr2O3, NiO, NiCr2O4, and Fe2O3 in the marine atmospheric environment. After accelerated corrosion, corrosion pits emerged on the alloy surface, accompanied by a decrease in the alloy's corrosion potential from-154.23 mV to-401.75 mV, an increase in the corrosion current density from 0.0037 mu A/cm2 to 0.0733 mu A/cm2, an approximate 60 % reduction in the thickness of the passive film. The creep life drops substantially, and under a stress of 80 MPa, the steady-state creep rate increases by 73 times compared to that before corrosion. In addition, the creep mechanism changes from being jointly dominated by diffusion and dislocations before corrosion to being dominated by dislocations. This study reveals the relationship between the long-term marine atmospheric environment and both the corrosion and creep behaviors of the K4648 alloy, and highlights the corrosion in the marine atmospheric environment which should be regarded as a core challenge that must be overcome for superalloys under actual working conditions.

High-temperature titanium alloys are significant materials in the aerospace field, and their service life largely depends on creep aging. However, the creep behavior of the TC25 titanium alloy at high temperatures has not been reported. Here, the creep behavior of TC25 before and after heat treatment at 550 °C under different stresses was investigated. It was found that heat treatment significantly enhanced the creep resistance of the TC25 alloy. An increase in creep stress increased the steady-state creep rate and reduced creep life. The smooth αp/βtrans grain boundaries and refined αs improved creep resistance, and the creep mechanism changed from grain boundary sliding to dislocation climbing after heat treatment. This research provides theoretical data support for the application of the TC25 alloy at high temperatures.

Room-temperature photocatalytic carbon dioxide reduction reaction (CRR) is an essential method for reducing carbon footprint and achieving valuable fuels. The key challenge to accelerating the process is enhancing the catalytic rate and product selectivity. Herein, we investigate the conversion of carbon dioxide to formic acid on Bi-doped CeO2 in the presence of tensile and compressive strain by using density functional theory corrected for on-site coulombic interactions. As demonstrated, the dopant atom not only benefits the oxygen vacancy formed, but also transfers some electrons to the Ti3+ site, which is the main catalytic site for the CRR. The promising model has excellent product selectivity, offering the best catalytic performance for formic acid (Delta G(max) = 0.64 eV). Moreover, the catalytic performance is further improved by the compressive strain. The work provides novel insights into designing environment-friendly and low-cost CeO2-based photocatalysts for carbon reduction.

Environmentally friendly ammonia production is important for addressing the carbon emissions and substantial energy consumption that are currently associated with the chemical industry. In recent decades, many achievements are made in this area; however, low production yield, poor selectivity, and unsatisfactory Faradaic efficiency hinder large‐scale applications. 2D, metal‐free electrocatalysts stand out from other candidates because of their physical, electronic, and chemical properties. In this study, recent developments of 2D‐based electrochemical materials for converting dinitrogen into ammonia in ambient conditions are systematically reviewed. First, recent unique progress and challenges on novel 2D electrocatalysts for the nitrogen reduction reaction are summarized. Then, various synthetic strategies for electrochemical materials and the influence of these methods have on the intrinsic material performance are highlighted. Last, by comparing current engineering strategies, electrochemical tests, and computational calculations, the opportunities, critical issues, and scientific challenges for 2D nanomaterials as stable, efficient catalysts, are analyzed. On the basis of this comparison, technology solutions are provided and rational principles for future studies are proposed.

背景:在钛金属表面改性和涂层化修饰的方案中,表面纳米管改性及羟基磷灰石涂层修饰构建的药物缓释体系具有广阔的临床应用前景.目的:构建载盐酸万古霉素的二氧化钛纳米管/羟基磷灰石复合载药涂层,研究复合涂层的体外药物缓释性能及细胞毒性.方法:以两步阳极氧化法在钛表面制备二氧化钛纳米管涂层,再通过电泳沉积方法制备羟基磷灰石涂层,从而得到钛基表面纳米管/羟基磷灰石的复合涂层结构.随后以该复合涂层为药物承载平台,通过物理吸附方式进行盐酸万古霉素的装载,最终得到载药复合涂层.检测载药二氧化钛纳米管涂层、载药羟基磷灰石涂层、载药复合涂层的体外释药性能.利用不同浓度的载药复合涂层浸提液培养人成骨细胞,采用MTT法检测细胞毒性.将人成骨细胞分别接种于羟基磷灰石涂层、二氧化钛纳米管涂层、载药复合涂层表面,观察细胞形态变化.结果 与结论:①相较于载药二氧化钛纳米管涂层与载药羟基磷灰石涂层,载药复合涂层具有更长的药物缓释效能,药物释放时间超过了150 h;②在10％,50％,100％浓度的载药复合涂层浸提液中,成骨细胞的相对活性均＞70％,无明显细胞毒性;③3种涂层表面的成骨细胞生长良好,细胞骨架完整,细胞的核质比例正常,与单纯培养的细胞形态无明显无别;④结果表明,二氧化钛纳米管/羟基磷灰石/盐酸万古霉素涂层具有良好的体外药物缓释性能,无明显的细胞毒性.

通过前驱体水热法成功制备出不同镍掺杂比例的二氧化钛纳米管粉体,利用场发射扫描电镜(FESEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、紫外可见吸收光谱(UV-Vis)等对其进行检测表征.制备出的镍掺杂二氧化钛纳米管具备相对分离和独立的管状形貌,管径约10 nm,其对应的EDS谱图中出现了镍的特征峰.经500 ℃热处理后样品呈锐钛矿和晶红石的混晶结构.XPS检测表明掺杂样品中镍主要以Ni2+形式存在.样品的紫外可见吸收光谱表明镍掺杂样品的光吸收发生红移且镍掺杂明显提升了样品的光吸收能力.光催化测试表明适宜的镍掺杂能够有效降低二氧化钛光生电子和空穴的复合率,从而提升了纳米管样品对亚甲基蓝的降解率.其中2％镍掺杂纳米管对亚甲基蓝显示出最高的2h降解率,达到95.7％,而过量的镍掺杂则会对其催化性能产生抑制作用.

In recent years, the rapid development of the rare earth industry has had a serious impact on the environment. Some enterprises have taken measures to improve the production process. In order to explore the sustainability of this industry and these improvements’ environmental benefits, this paper combines emergy analysis and lifecycle assessment to evaluate and compare the production process of rare-earth oxides considering the three aspects of emergy flow, pollutant emissions, and emergy-based indicators. Changes in the emergy of pollutant emissions before and after improvement of the production process are discussed. The results show that the greatest inputs in the mining and beneficiation stage and smelting separation stage are labor force and service and non-renewable resources, respectively. These two production stages are highly dependent on external input and have weak competitiveness. Both stages place great pressure on the environment, so the bastnasite production process would be unsustainable in the long term. After the improvement, the environmental impact of the production process for bastnaesite changed significantly, indicating that the improvement effect of the wastewater treatment facilities and the change of fuel from coal to natural gas is remarkable.

Benefitting from a suitable band gap, ceria is an excellent material for UV shielding. By solid solution doping and specific micromorphology, its band gap can be effectively controlled. In this paper, ceria doped with lanthanum via oxalate precipitation is combined with a high-temperature roasting process. The properties of the prepared samples are characterized by UV–Vis diffuse reflectance spectroscopy (DRS), Raman, XRD, FESEM and XPS. The absorption threshold of materials is clearly red-shifted in the ultraviolet band, which originates from the electron-phonon generation. To further reveal the mechanism, the density function theory calculation (DFT) is implemented to study the influence of lanthanum concentrations on ceria’s band gap. It is demonstrated that the band gap can even be narrowed to 2.97 eV by optimizing the sintering temperature and lanthanum-doped concentration. To investigate its improved anti-aging properties under ultraviolet rays, different amounts of 5% lanthanum-doped ceria is mixed with an Al-based coating and then coated on the Q235 steel. Combined with an ultraviolet light irradiation experiment and electrochemical test technology, the corrosion resistance of the modified coatings is evaluated. The coating with 20% La-doped ceria provides the best corrosion resistance performance.

以循环流化床(CFB)粉煤灰为初始铝源,进行了高纯单分散球形纳米氧化铝的制备研究.对CFB粉煤灰的组成与结构进行分析及提取Al2O3的浸取条件进行优化;采用盐析及重结晶联合法对浸取铝盐进行除杂研究;除杂产物采用分散剂GUMA辅助均匀沉淀法制备球形单分散纳米α-Al2O3.结果表明,以CFB粉煤灰为初级铝源,可制备出纯度达99.99％,粒径为200nm,且分散性高、球形圆度好、粒径分布窄的α-Al2O3.

Nano-sized hydroxyapatite (nHA) particles have been demonstrated to exert anti-cancer effects on multiple cancer cell lines and animal models of cancer biology. However, the molecular mechanism underlying the effects of nHA particles on glioma cells remains unclear. The present study aimed to examine the effects of nHA on the behavior of glioma cells and investigate its underlying molecular mechanism. Rat glioma C6 cells and human glioma U87MG ATCC cells were exposed to nHA (20-100 µg/ml), and its effects on cell morphology, viability, apoptosis, cell cycle, invasion and nuclear factor (NF)-κB signaling were analyzed. Exposure of C6 and U87MG ATCC cells to 20 µg/ml nHA for 24 h caused cell detachment. Viability of C6 and U87MG ATCC cells were significantly reduced by nHA in a dose-dependent manner (P<0.05). Nuclear staining with Hoechst 33258 exhibited clear chromatin condensation in C6 cells following 24 h exposure to ≥25 µg/ml nHA. Flow cytometry revealed that nHA (20-100 µg/ml) significantly induced apoptosis and cell cycle G2/M arrest in C6 and U87MG ATCC cells (P<0.05). Transwell invasion assay demonstrated that nHA (20-60 µg/ml) significantly inhibited invasion of U87MG ATCC cells (P<0.05). Furthermore, western blotting and confocal immunofluorescence microscopy revealed that nHA (20-100 µg/ml) decreased NF-κB p65 protein expression and blocked NF-κB p65 nuclear translocation in C6 cells. The protein expression of NF-κB target molecules, such as B cell lymphoma 2, cyclooxygenase-2 and survivin, were also significantly reduced by nHA in a dose-dependent manner in both C6 and U87MG ATCC cells (P<0.05). In conclusion, it was demonstrated that the inhibitory effect of nHA on glioma cells is likely associated with the downregulation of NF-κB signaling.

重稀土热扩渗技术在制备高性能、低成本烧结NdFeB磁体领域有重要的应用前景.本研究利用涂覆工艺将DyF3粉末均匀涂覆在M档商业烧结NdFeB磁体表面,获得均匀DyF3涂层,然后进行热扩渗处理.对热扩渗后磁体的性能,微观组织结构及元素分布进行分析,讨论了NdFeB磁体热扩渗工艺对其性能的影响及热扩渗机制.结果 表明,本研究磁体的最佳渗Dy工艺为920℃×5h,磁体的矫顽力提高了428 A/m,达到1555 A/m,剩磁下降很小,磁体达到最佳的综合性能.在扩渗过程中,浓度差提供了扩渗的驱动力,在其驱动下,Dy元素从表面经由晶界向芯部扩散,距磁体表面约689μm范围内,Dy元素扩渗充分且均匀,超过该范围后Dy元素开始出现梯度分布,在本扩渗工艺Dy元素可渗透3mm厚度的磁体.

Perovskite-type oxides have become the hotspots of functional materials due to their various excellent performances. As a typical material with a perovskite structure, CaTiO3 (CTO) possesses a similar band gap to TiO2 with less defects and recombination centers, which makes it a promising alternative material to TiO2. In particular, the CTO nanotube structure has a large specific surface area and unique photochemical and electron-transport properties, and these advantages further expand its application range. In this paper, a highly ordered and vertically aligned CTO nanotube array was successfully synthesized by a simple hydrothermal method with TiO2 nanotube (TNT) arrays as the precursor. It was found that the CTO nanotube had a higher optical absorption ability (3.4 eV), photovoltage (500 mV) and photocurrent density (0.004 A cm-1) under ultraviolet irradiation, compared to the TNT (350 mV and 0.0036 A cm-1). At the same time, the electrochemical impedance spectroscopy, Mott-Schottky and stability tests indicate that the CTO nanotube might be a promising alternative choice as the photoelectric material for a TNT.

The heterogeneous Fenton system has become the hotspot in the decontamination field due to its effective degradation performance with a wide pH range. Based on the unstable chemical properties of pyrite, in this article, Fe2GeS4 nanoparticles with better thermodynamic stability were prepared by vacuum sintering and high energy ball milling and its potential as Fenton reagent was investigated for the first time. Three determinants of the heterogeneous Fenton system including the iron source, hydrogen peroxide, pH and the degradation mechanism were investigated. The catalyst dosage of 0.3 g/L, initial H2O2 concentration in the Fenton system of 50 m mol/L and pH of 7 were chosen as the best operational conditions. An almost complete degradation was achieved within 5 min for methylene blue and rhodamine b while 10 min for methyl orange. The total organic carbon removal efficiencies of Fe2GeS4 heterogeneous Fenton system for methylene blue, methyl orange and rhodamine b in 10 min were 56.3%, 66.2% and 74.2%, respectively. It's found that the degradation ability could be attributed to a heterogeneous catalysis occurring at the Fe2GeS4 surface together with a homogeneous catalysis in the aqueous phase by the dissolved iron ions.

The geometric structures, formation energies, electronic structures and magnetic properties of Ni-doped anatase, with different concentrations and doping methods, were studied by the first principle method under the framework of the spin density functional theory, combined with the crystal field theory. The results of formation energy calculation show that the oxygen environment, in the process of crystal growth, has an important influence on the structures of Ni-doping. Analysis of the state density and energy level track map showed that the valence states of Ni ion was different in different doping conditions. Impurity energy levels in the bandgap of all kinds of doping system are formed by the hybridization of Ni3d-02p. When a doping Ni ion substitute lattice Ti, that will make the unit cell volume and the crystal stability decrease, absorption spectrum red shift, the system is paramagnetic. Interstitial Ni doping makes the unit cell volume increase, the absorption spectrum blue shift, and enables the band to move in the direction of low energy. At this time, the carrier occur n type-degeneration, the ability, of some Ti ions, of losing electrons declined, resulting in the making of Ti3+ ions, the system has magnetism.

BACKGROUND: Both hydroxyapatite (HA) and large diameter TiO2 nanotubes have excellent biocompatibility, but bone-forming ability of nano-HA (nHA) deposited large diameter TiO2 nanotubes is rarely reported.OBJECTIVE: To evaluate the bone-forming ability of nHA/large-diameter TiO2 nanotube composite coating.METHODS: Large-diameter TiO2 nanotubes were prepared by anodic oxidation method, and then nHA was electrochemically deposited on the surface of TiO2 nanotubes. Preosteoblasts MC3T3-E1 were co-cultured with the nHA/large diameter TiO2 nanotube composite, pure titanium and TiO2 nanotube coatings, respectively. At 0.5, 1, 2 hours after culture, the initial cell adhesion was observed. At 1, 3, 5 day after culture, cell proliferation was assessed. At 2 days after culture, cell morphology was observed. At 3 and 7 days after osteogenic induction, intracellular alkaline phosphatase activity was detected. At 14 days after osteogenic induction, mineralization of extracellular matrix was detected.RESULTS AND CONCLUSION: (1) After 2 hours of culture, the number of adherent cells on the composite coating was significantly lower than that on the TiO2 nanotube coating (P < 0.05), but slightly higher than that on the pure titanium coating with no statistical difference. (2) After 1, 3, 5 days of culture, the cell proliferation on the composite coating was significantly lower than that on the TiO2 nanotube coating (P < 0.05), but slightly higher than that on the pure titanium with no statistical difference. (3) The cells on the pure titanium showed a spindle-shape, while those on the TiO2 nanotube coating processed filopodia. The cells on the composite coating showed polygonal shape with a larger number of filopodia. (4) The intracellular alkaline phosphatase activity of the composite coating group was significantly higher than that of the pure titanium group and TiO2 nanotube group. The trend of mineralization of extracellular matrix was ranked from high to low: the composite coating group > TiO2 nanotube group > pure titanium group. To conclude, the nHA/large diameter TiO2 nanotube composite coating not only has good biocompatibility, but also has the ideal ability to promote bone formation.

Ag-Ti nanotube array was prepared by simple anodic oxidation method and uniform hydroxyapatite were electrochemically deposited on the nanotubes, and then characterized by SEM, XRD, XPS and EIS. In order to investigate the influence of Ti3+ on the electrochemical deposition of hydroxyapatite on the nanotubes, the Ag-Ti nanotube array self-doped with Ti3+ was prepared by one step reduction method. The experiment results revealed that the Ti3+ can promote the grow rate of hydroxyapatite coatings on nanotube surface. The hydroxyapatite coated Ag-Ti nanotube arrays with Ti3+ exhibit excellent stability and higher corrosion resistance. Moreover, the compact and dense hydroxyapatite coating can also prevent the Ag atom erosion from the Ag-Ti nanotube. (C) 2017 Elsevier B.V. All rights reserved.

BACKGROUND:Implant-related infection is a major problem postsurgery. As an alternative to a localized antibiotic release system, we used Ag to fabricate Ti-Ag alloys with nanotubular coatings (TiAg-NTs). Ag has excellent antibacterial properties, but its biological toxicity is a concern. Therefore, we performed biological experiments both in vitro and in vivo to evaluate the biocompatibility of TiAg-NTs with different concentrations of Ag (1%, 2%, and 4%).METHODS:For in vitro experiments, cytocompatibility, including cell attachment, viability, and proliferation, was tested, and genes and proteins related to osteogenic differentiation were also evaluated. For in vivo assays, the rat femoral condylar insertion model was used, and micro-computed tomography (micro-CT) and histological analysis were conducted to analyze bone formation around implants at 1, 2, and 4 weeks after surgery.RESULTS:Both in vitro and in vivo results indicate that Ti2%Ag-NT showed comparable cytocompatibility with commercially pure Ti (cp-Ti), and it could achieve good osseointegration with the surrounding bone tissue.CONCLUSION:We thus believe that Ti2%Ag-NT is a potential biomaterial for orthopedics.