Surfaces and Interfaces最新文献

Nano-oxides are largely responsible for the excellent mechanical properties and irradiation tolerance of nano-structured ferritic alloys (NFAs) for nuclear reactor applications. In this work, the roles of perovskite YTiO₃ and its interface in trapping helium in NFAs were investigated from the first-principles. Similarly as other two Y-Ti-oxide phases (Y₂TiO₅ and Y₂Ti₂O₇), bulk YTiO₃ can trap insoluble helium at its interstitial sites, but with a lower trapping ability that is only comparable to matrix vacancies. The ferrite/YTiO₃ interface phase diagram was constructed based on the experimental orientation relationship and the calculated interface formation energy, and the lowest-energy interface structure was predicted as the ns-Ti or the stoichiometric. Helium always prefers to consume individual interfacial vacancies and interstitial sites to the extent possible, before forming higher-order helium-vacancy clusters at the interface. Similarly as Y₂Ti₂O₇, YTiO₃ preferably traps helium at its interface, followed by its bulk interior and the ferritic matrix. However, in view of all the bulk and interface results, perovskite YTiO₃ cannot compete with pyrochlore Y₂Ti₂O₇ in trapping helium in NFAs.

All over the world, there are stringent regulations in place concerning the acceptable amount of pesticide residues in various food commodities, including cereals. The majority of the water tainted with pesticides comes from agricultural drainage, making it imperative that this water be cleansed of any lingering traces of the chemicals. The presence of unacceptable levels of pesticides residues is another issue hindering India's ability to export Basmati rice and other commodities. Tricyclazole, a fungicide has been found in rice in recent years, leading to the rejection of a number of bulk consignments. Therefore, three metal organic frameworks (MOFs) viz., MIL-53(Al), Fe-BTC, and ZIF-8, based on three different metal ions (aluminium, iron, and zinc) and three different organic "struts" were investigated for the removal of TRCZ from water. Interestingly, TRCZ was found to be selective towards both metal ions and linkers. The maximum adsorption capacities of TRCZ onto MIL-53(Al), Fe-BTC and ZIF-8 were 980.0, 896.7 and 904.6 μg g⁻¹ (@1 ppm aqueous solution), respectively. Adsorption followed pseudo-second-order kinetics and best fit the Sips isotherm. The adsorption of TRCZ molecules onto the surface of the MOFs were confirmed using Fourier Transform infrared (FTIR) and X-Ray Diffraction (XRD) spectroscopy. MIL-53(Al) showed the best regeneration capacity (> 90 % efficiency after the 4th cycle). The adsorption of pesticide molecules onto MOF surfaces was studied (in vacuo and in aqueous) circumstances using Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) simulations revealing the prime competitive role of water molecules aided by π-π stacking and π-lone pair interactions during adsorption. Metal organic frameworks have the potential to replace costly commercial activated carbons in the future to treat pesticide-contaminated water.

In this study, utilizing density functional theory, the C₃N₁ monolayer modified by Ir, Pd, Pt, and Rh atoms (Ir/Pd/Pt/Rh-C₂N₁) was chosen for selective adsorption of C₂H₂ amidst multiple gases (H₂O, C₂H₂, and C₄H₁₀O₂). According to the results of cohesive energy and ab initio molecular dynamics simulations, it is indicated that precious metal atoms can be stably anchored on the monolayer while enhancing the conductivity of the material The analysis of the electrostatic potential and work function determined the highly active sites and electron release capacity. In addition, the adsorption energy and distance disclosed the gas-solid interface structure of multiple gases on the Ir/Pd/Pt/Rh-C₂N₁ monolayer. Importantly, C₂H₂ exhibits strong responses to p-type semiconductor Pt-C₂N₁ and n-type semiconductor Ir-C₂N₁, respectively. Crystal Orbital Hamilton Population reveals the difference in adsorption energy due to modifications involving four precious metals. Interestingly, for the first time, the density of states calculation reveals that under the coexistence of multiple gases, the Pt/Ir-C₂N₁ monolayer effectively eliminates the interference of other gases and has a unique response only to C₂H₂. In real situations, with the basis of Gibbs free energy and Einstein's law of diffusion, it was determined that Pt-C₂N₁ and Ir-C₂N₁ showed excellent hydrophobicity, a wider temperature range, and a low diffusion activation energy barrier. In summary, Pt-C₂N₁ and Ir-C₂N₁ detect C₂H₂ without interference, maintaining fundamental principles, responsiveness, stability, and versatility unaffected by external factors.

Titanium surface nanostructuring using alkali treatment gains significant attention in a wide range of fields, such as biomaterials, (photo)catalysis, (metal/ion) sorption, CO₂ capture, electrochromism and sodium-ion batteries. Even though the physicochemical properties and application potentials of the surface nanostructures are fairly well understood, there is still debate about their exact formation mechanism, limiting knowledge based structural control through altered synthesis conditions. Moreover, this knowledge is largely focused on hydrothermal synthesis conditions, whereas non-hydrothermal conditions might provide benefits towards industrial application. Also the impact of substrate properties, rather than chemical reaction conditions, on the nanostructure formation is only limitedly reported in literature. This work reveals new fundamental knowledge of non-hydrothermal alkali treatment of titanium, using microspheres by implementing, for the first time, in-situ hydrogen measurement during alkali treatment in combination with the ex-situ determination of the sodium and oxygen content in the recovered alkali treated samples, providing critical information on the role of dissolution apart from the precipitation process. The effect of surface area and surface curvature on the dissolution and precipitation process, and the resulting impact on the physicochemical properties of the obtained titanate layer is studied. This shows the much larger impact on dissolution in contrast to precipitation, knowledge that is lacking in literature, but important when implementing alkali surface nanostructuring on complex (e.g. 3D printed) substrates, and considering the prospective shift from lab-scale to industry. The Ti dissolution step was found to be mainly controlled by the total surface area, while the rate determining step was found to be the titanate precipitation, not influenced by either surface area or particle size.

The changes in oxygen content in the samples after transformation of titanate into TiO₂ provided a novel method for its quantification. The microspheres were analysed chemically (Raman), structurally (XRD) and morphologically (SEM, MIP), screening the effect of surface area, particle size and reaction time on the growth behaviour of the titanate layer. The porous layer structurally corresponds to Na₂Ti₂O₄(OH)₂ for all evaluated conditions, with pores in the range of 10–600 nm. Increasing surface area and particle size results in local and non-uniform titanate growth, while titanate nanowire and strut formation between the microspheres were enhanced by reduced microsphere size and prolonged reaction times.

Schottky contacts at the ferromagnet/ZnO interface are good candidates for the realization and control of several semiconductor emerging magnetic phenomena such spin injection and spin-controlled photonics. In this work, we demonstrate the epitaxial growth of single-phase and wurtzite-ZnO thin films on fcc Pt/Co_0.30Pt_0.70 (111) electrodes by molecular beam epitaxy technique. While the magnetic properties of the Pt/Co_0.30Pt_0.70 buffer remain unchanged after the ZnO growth, the electric measurements of back-to-back Schottky diodes reveal Schottky barrier heights at the metal/ZnO interfaces in the range of 590–690 meV using Cu, Pt and Co_0.30Pt_0.70 contacts. A pinning factor S and a charge neutrality level (CNL) Φ_CNL of 0.08 and 4.94 eV, respectively, are obtained indicating a strong Fermi-level pining with a CNL level that lies 0.64 eV bellow the conductance band of ZnO semiconductor. These experimental findings indicate that Co_0.30Pt_0.70/ZnO interface follows the metal-induced gap states model and can open a pathway for the realization of opto-spintronics applications such spin-LEDs.

Ice can lead to inconvenience and disasters in human activities, making it a widely concern for researchers to find solutions to prevent icing. Hydrophobic materials have been developed for passive anti-icing with a long time, but without active deicing effect. Recently, researchers have explored hydrophobic photothermal materials with passive anti-icing and active deicing ability, which are limited on cloudy days and the night. Consequently, developing materials with anti-icing/icephobic and deicing capabilities for all-weather use has emerged as an innovative strategy. This paper develops hydrophobic PDMS/Cu-Ni@PET with photo/electric thermal properties to support all-weather anti-icing/icephobic and deicing, which is synthesized using copper-nickel and hydrophobic polydimethylsiloxane (PDMS). The PDMS/Cu-Ni@PET exhibits an outstanding anti-icing performance with a delayed icing time of 1224 s at -10 °C, and achieves a surface equilibrium temperature of 68.9 °C under 1 sunlight intensity, enabling the melting of surface ice particles within 614 ± 118 s. When a voltage is applied to both sides of the fabric, the equilibrium temperature can be reached within 60 s, and attained 158 °C at 6 V, enabling the melting of surface ice within 97 s. It provides a novel approach for developing photo/electric thermal superhydrophobic coatings that can maintain all-weather deicing performance.

Solar-light driven organic pollutants degradation by the recyclable photocatalytic membrane materials emerges as a promising technology for sewage purification. However, low generation of reactive oxygen species severely constraints their photocatalytic activity. Herein, we introduce a novel hydrophilic PU/SF/GO/AgI composite photocatalytic membrane fabricated via adding silk fibroin (SF) and graphene oxide (GO) for TC removal. By visible light irradiation, the PU/SF/GO/AgI membrane with 66.7 wt% SF and 0.05 wt% GO degrades TC with 7-fold increase in comparison with the PU/AgI membrane. The enhance photocatalytic activity is primarily attributed to its efficient generation of reactive oxygen species facilitated by the improved hydrophilicity and boosted charge separation. FTIR and electrochemical results demonstrate that the SF and GO with rich surface oxygen-containing groups contribute to the formation of Ag-O bonds for accelerating charge migration and separation. Significantly, the improved hydrophilicity of PU/SF/GO membrane can not only provide rich binging sites for AgI loading, but also be benefitted to attract small molecules for facilitating to reactive oxygen species generation. As a result, ^•O₂⁻, ^•OH and H₂O₂ concentrations produced in PU/SF/GO/AgI membrane system reaches up to 53.20 μmol g⁻¹ h⁻¹, 7.89 μmol g⁻¹ h⁻¹ and 16.52 μmol, respectively, 6.7, 15.4 and 5.1-times higher than PU/AgI membrane system. Meanwhile, under LED irradiation of 12 h, TC degradation efficiency by the dynamic membrane reactor equipped with PU/SF/GO/AgI can reach up to 53 % and achieve 41 % TOC removal, exceeding the pure PU/AgI and those of reported membrane materials. This work proves that tuning hydrophilicity and charge migration of PU membrane can enhance their photocatalytic activity and recyclability, which offers an effective strategy for constructing sustained solar-light driven photocatalytic membrane system.

Novel brominated flame retardants (NBFRs) pose serious risks to aquatic organisms and human health due to their persistence and toxicity. Herein, sulfate ions (SO₄^2-) decorated C₃N₄ (SO₄^2-@CN) photocatalyst material was synthesized for the rapid degradation of NBFRs by a synergistic effect of photocatalytic oxidation and reduction reactions. Compared with bare C₃N₄, the SO₄^2-@CN exhibited efficient photocatalytic NBFRs removal performance. The degradation rates constant of hexabromobenzene and pentabromotoluene by SO₄^2-@CN were 0.177 and 0.0906 min^-1, respectively, which were 2.9 and 6.7 times higher than that by C₃N₄. It was confirmed that SO₄^2-@CN could generate more active substances (such as sulfate radicals, and hydroxyl radicals) and promote the oxidation of NBFRs. Meanwhile, SO₄^2- accelerated the separation of photogenerated electron-holes by promoting the formation of hydrogenated structures, allowing more photogenerated electrons to participate in the debromination reduction process. This work provides a new insight for the practical application of visible light driven photocatalytic technology in NBFRs residues degradation.

Hf₆Ta₂O₁₇, with low thermal conductivity, high thermal expansion coefficient, and excellent fracture toughness, was a promising candidate ceramic top coat material of thermal barrier coating (TBC). A novel Hf₆Ta₂O₁₇/YSZ double ceramic top coat prepared by atmospheric plasma spraying (APS) was applied to study the role of the microstructure and mechanical property on the thermal cycling property at 1200 °C. Results show that the rapid decomposition of Hf₆Ta₂O₁₇ occurred during the spraying process. As the increased spraying power, more HfO₂ phases were observed in the Hf₆Ta₂O₁₇/YSZ TBCs. Besides, the porosity of the Hf₆Ta₂O₁₇ ceramic top coat decreased with the increased spraying power, resulting in the elastic modulus of the Hf₆Ta₂O₁₇ ceramic top coat enhancement. The highest cycles at 1200 °C were obtained for the Hf₆Ta₂O₁₇/YSZ TBCs with the lowest elastic modulus and least HfO₂ phases, and were twice as long as the cycles of the single YSZ TBCs. The chemical reaction between HfO₂ and Hf₆Ta₂O₁₇ might have contributed to the cracking of the Hf₆Ta₂O₁₇/YSZ TBCs. This work provides a new option for the preparation and development of the ternary oxides by APS.

Pollution triggered by organic dyes is a prominent global concern. Thus, it is imperative to devise an effective preventative strategy to tackle this matter. Herein, using the chemical electroless deposition process, a novel SiNWs/MnO₂ photocatalyst was successfully manufactured for efficacious photocatalytic purification under visible lighting. Through a series of characterization techniques, the structural, morphological, compositional, and optical features of MnO₂-deposited silicon nanowires were thoroughly investigated. The photocatalytic ability of the resultant sample was reckoned by degrading Rhodamine B upon visible exposure. Following 180 min of brightness, the findings found that SiNWs/MnO₂ displayed remarkable effectiveness, with a lessening of 93.4 %. The findings demonstrated a significant enhancement in degradation performance linked to the rising surface area and enhanced electron-hole segregation efficiency provided by silicon nanowires. Also, the sample's recyclability was assessed, exhibiting an encouraging sustainability with a slight fall in effectiveness (∼10%) after 6 straight utilizes. Furthermore, scavenging tests have shown that •OH and •O₂⁻ were prevalent species accountable for the RhB degradation reaction. Eventually, founded on the results, a plausible mechanism for RhB decomposition was suggested. Altogether, given the straightforward manufacturing method and impressive performance, the study argues that the novel SiNWs/MnO₂ might be an intriguing photocatalyst for water contaminant remediation.