MATERIALS & DESIGN
·
2017
·
IF 4.364
Jie Zhang,Zhenxing Yue,Yu Luo,Xiaohua Zhang,Longtu Li
Relaxation phenomena in dielectrics are well known to be closely related to their defect chemistry. However, the relaxation behavior of microwave dielectrics has seldom been considered, despite these materials being an important member of the electroceramic family. Here, the relaxation behavior of the typical microwave dielectric ceramic barium tetratitanate (BaTi 4 O 9 ) was investigated. Significant thermally stimulated relaxation was observed in both dielectric spectroscopy and thermally stimulated depolarization current (TSDC) measurements, and the correlation between relaxation and defect behavior was addressed. TSDC characterization revealed that defect dipoles [(Ti Ti ' )−(V O •• )] with activation energies ( E a ) of 0.32–0.36 eV appeared at low temperature, while in-grain and across-grain boundary oxygen vacancies (V O •• ) appeared at higher temperature, yielding E a of 0.30–0.48 eV and 0.65–1.01 eV, respectively. It was further believed that these two types of defects, (Ti Ti ' )−(V O •• ) and V O •• , were correspondingly responsible for the dielectric relaxation observed at low and high temperature. The relaxation behavior of several typical Ti-containing microwave dielectrics, such as BaTi 4 O 9 , TiO 2 , MgTiO 3 and Ca 0.8 Sr 0.2 TiO 3 , was compared, which suggests that microwave dielectric performance and defect behavior are closely related to the connections of TiO 6 octahedra in the materials.
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Materials Science and Engineering B-Advanced Functional Solid-State Materials
·
2025
·
IF 4.6
Yiqing Wu,Xiangmei Ma,Bin Wang,Yanan Li,Shengtao Gao
The detrimental effects of ultraviolet (UV) and electromagnetic (EM) radiation on human health and physiological functions are well documented. The development of efficient shielding materials to mitigate these effects is therefore an urgent necessity. In this study, Zn/Ti-LDH@Ce/Fe-MOF@PPy composites were successfully prepared by hydrothermal synthesis and interfacial polymerisation. The properties of the composites were compared and analysed with those of pure Zn/Ti-LDH and Ce/Fe-MOF, and the results show that the prepared materials have excellent comprehensive properties, with a broad EAB of 5.2 GHz and a RL min of −46.2 dB at 14.8 GHz at the thickness of 3 mm, while exhibiting excellent UV shielding capability.The present study offers novel concepts and efficacious methodologies for the engineering of high-performance microwave absorbing and UV shielding materials.
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xiumei Wu,Yunping Li,Xiangming Chen,Shu Yu
Ti doping SiTiOC ceramics were prepared by sol-gel method with tetrabutyl titanate (TBT) as modifier. The thermal stability of SiTiOC ceramics with various Ti contents was studied. Meanwhile, the influence of Ti addition on the pyrolysis behavior of SiTiOC xerogel and the structure evolution of SiTiOC ceramics were investigated. The ceramic yield of SiTiOC xerogels were improved greatly by introducing TBT, while the improvement of ceramic yield had an upper limit, for the simultaneous increase of volatile CH 3 O(CH 2 ) 3 OH. At 900 °C pyrolysis, SiTiOC ceramics were amorphous, and Ti existed by oxides. At 1200 °C and 1400 °C pyrolysis, the crystallinity of SiTiOC ceramics increased, TiC phase appeared in ceramics due to the carbothermal reduction of titanium oxides. With increased Ti contents, TiC contents increased in ceramics attributed to the preferentially carbothermal reduction of titanium oxides. The addition of Ti improved the thermal stability of SiOC ceramic system, but such an improvement was sensitive to the Ti contents. 0.05Ti-1400 ceramic exhibited the highest thermal stability with the mass change of 6.51 %. Because the oxide scale of 0.05Ti-1400 ceramic was complete and dense, with lowest thermal stress and oxygen diffusion rate for the least TiO 2 formed in the oxide scale. Concurrently, the TiO 2 particles formed with long rod-like which distributed uniformly in oxide scale that can toughen the oxide scale. While for 0.1Ti-1400 and 0.2Ti-1400 ceramics, the increase of Ti outward diffusion degree damaged the oxide scale and accelerated the oxidation of free carbon.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
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IF 6.3
Changyan Guo,Cheng Guo,Shuai Yang,Naeem Akram,Yonghong Zhang,Jide Wang
Controlling the excessive oxidation of 1,4-Benzenedimethanol (1,4-BDM) to selectively produce high-value-added 4-hydroxybenzaldehyde (4-HB) under mild conditions while simultaneously generating H 2 is a challenging problem. In this study, it was found that incorporating Ni into cadmium sulfide (CdS) significantly reduces the bandgap of CdS and adjusts its conduction band position, yet still leads to over-oxidation of 1,4-BDM. To enhance selectivity, we designed and synthesized a bifunctional photocatalyst, CdS-Ti/Ni, with a petal-like structure by integrating both Ni and Ti with CdS. This composite exhibits a bandgap of 2.3 eV, and the synergistic effects of Ti and Ni result in more favorable valence and conduction band positions, thereby demonstrating superior photocatalytic efficiency and selectivity. Within the first 30 minutes, the bifunctional CdS-Ti/Ni achieved a 73 % selectivity for 4-HB. The H 2 evolution rate reached 20.2 mmol·g −1 ·h −1 , which is 13 times higher than that of pure CdS. This study demonstrates that bimetal doping can adjust the energy band structure, photocatalytic H 2 production efficiency and oxidation selectivity of semiconductor materials, offering valuable insights for the design of efficient bifunctional photocatalysts.
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JOURNAL OF CATALYSIS
·
2025
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IF 6.5
Yuexia Wang,Jiaqi Xu,Xuan Lin,Chaosi Liu,Xinqing Lu,Yijing Gao,Francesco Pepe,Domenico Caputo,Weidong Zhu
Ti-MWW zeotypes, characterized by their unique dual pore architecture consisting of intralayer 10-membered ring (MR) pore channels and additional interlayer 10-MR pore channels that are interconnected to intracrystalline 12-MR supercages, exhibit a remarkably catalytic superiority in the selective oxidation of small and/or linear alkenes with hydrogen peroxide (H 2 O 2 ), surpassing other titanosilicate zeotypes in performance. However, a further improvement on their catalytic performance is still needed for the industrialization of alkene epoxidation over Ti-MWW. In the present work, the introduction of NH 4 + species into Ti-MWW was conducted via a facile but effective treatment of the as-synthesized zeotypes with NH 4 Cl, named N-Ti-MWW. The comprehensive characterization of N-Ti-MWW, derived from NH 4 + -exchanged Ti-MWW, coupled with Density Functional Theory (DFT) calculations, conclusively demonstrates that the integration of NH 4 + into Ti-MWW promotes the generation of -Ti-OOH hydroperoxo intermediates, resulting in a higher catalytic activity in alkene epoxidation in comparison to the parent one. Moreover, the solvolysis of epoxides is significantly suppressed on N-Ti-MWW, enabling the catalyst to display a superior selectivity towards the targeted epoxide, thereby improving its overall catalytic performance. Additionally, N-Ti-MWW is reusable, after the regeneration of the deactivated catalyst simply treated with NH 4 Cl. As a result, it is anticipated that N-Ti-MWW would be applicable in the industrial epoxidation of alkenes with H 2 O 2 .
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Processes
·
2024
·Vol. 12
·期 9
·1879
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IF 2.8
Huiying Yang,Xiangchao Meng
The conversion of nitrogen (N2) and water (H2O) into NH3by photocatalysis under ambient conditions has been considered an environmentally friendly strategy. However, developing effective catalysts for N2fixation is still challenging. Herein, we report a bimetallic JH Fe, Co/TiO2derived from NH2-MIL-125(Ti) by the fast Joule heating (FJH) method for visible–light–driven catalytic N2fixation. It was found that the photocatalytic N2reduction efficiency of bimetallic FC@TiO2-JH was improved, enabling an NH3yield rate of 110.14 µmol g−1h−1without any sacrificial agents. Furthermore, the rate was higher than those of Fe@TiO2-JH and Co@TiO2-JH, suggesting that the synergistic effect between Fe and Co broke the electronic equilibrium and increased the center of its d-band, enhancing electronic feedback to the antibonding π* orbitals of N2while weakening the bonding energy of N≡N. Meanwhile, the rate was about 2.75 times higher than that of FC@TiO2-TF, which was calcined in a tube furnace. It is assumed that FJH might lead to the formation of lattice defects, leading to localized charge deficiency, enhanced carrier separation, and transport. Thus, doping of Fe and Co synergistically interacted with the defects produced from FJH, facilitating the photocatalytic reduction process. As detected, it had a greater ability to separate hole–electron pairs and transferred electrons to adsorbed N2at faster rates. Our work demonstrates a prospective strategy for designing bimetallic catalysts derived from NH2-MIL-125(Ti) for N2fixation.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Zhuofan Han,Dengjie Zhong,Yunlan Xu,Haixing Chang,Lin Dong,Yi Liu
In this study, based on Ag@AgCl/tubular g-C 3 N 4 (Ag@AgCl/TCN) composite, Ag nanoparticles were deposited on its surface to form Ag nanofilm enhanced composite through photoreduction of excessive silver nitrate solution to obtain Ag nanofilm Ag@AgCl/TCN photocatalyst . Finally, Ag nanofilm Ag@AgCl/TCN/Ti photoanode was successfully prepared by silica-sol drop-coating method, and assembled with Cu 2 O/Cu cathode to construct a photocatalytic fuel cell (PFC). Ag nanofilm can not only enhance the light absorption and utilization of Ag@AgCl/TCN/Ti, but also extend its light response wavelength to visible light , and be used as an electron transfer medium to reduce internal resistance. The photocurrent density and the photoconversion efficiency of the Ag nanofilm/Ag@AgCl/TCN/Ti are 8.01 mA·cm −2 and 1.24%, respectively, which are 2.49 and 2.54 times those of the Ag@AgCl/TCN/Ti photoanode, respectively. The first-order kinetic constant and the maximum power density of the Ag nanofilm-coated Ag@AgCl/TCN/Ti-Cu 2 O/Cu PFC system are 0.064 min −1 and 46.37 μW·cm −2 , respectively, which are 1.39 and 1.94 times those of the Ag@AgCl/TCN-Cu 2 O/Cu PFC system, respectively. In addition, it degraded more than 95% of rhodamine B, 72.68% of tetracycline and 54.25% of bisphenol A within 60 min. The excellent performance of Ag nanofilm/Ag@AgCl/TCN/Ti-Cu 2 O/Cu is due to the strengthening of Ag nanofilm and the formation of S-type heterojunctions between AgCl and TCN. Free radicals (•Cl, h + , •OH, •O 2 - ) and non-radicals ( 1 O 2 ) are involved in the degradation reaction of RhB degradation. It is worth noting that 6% Ag nanofilm/Ag@AgCl/TCN/Ti-Cu 2 O/Cu has a positive effect on the production of •O 2 - , and its output is approximately 1.89 times that of the Ag@AgCl/TCN/Ti-Cu 2 O/Cu. A series of material characterization experiments have been completed and possible mechanisms of operation have been proposed. This study provides a new scheme for the design and preparation of high-efficiency photoanode of PFC.
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THIN-WALLED STRUCTURES
·
2025
·
IF 6.6
Meng Cao,Yewei Zhang,Mingyu Liu,Xuefeng Sun,Shuo Wang,Jian Zang
The insufficient bond strength at the fiber/metal interface of fiber metal laminates (FMLs) is a primary obstacle to their widespread application. To address this issue, a strategy is proposed to introduce graphene nanoplatelets (GNPs) to enhance the bond strength at the carbon fiber/polyether ether ketone (CF/PEEK)-titanium interface. This approach comprises two main components. First, GNPs were deposited onto the surface of the titanium layer to form a micro-nanolayer using electrophoretic deposition (EPD). The effects of varying voltages, deposition times, and GNPs concentrations on the EPD results were investigated. Second, the PEEK matrix was modified with GNPs to further enhance the interfacial bond strength of CF/PEEK-titanium. The results indicated that optimal EPD parameters-30 V, 90 s, and a GNP concentration of 0.75 mg/mL-yielded the best outcomes. Under these conditions, the flexural strength, interfacial shear strength, and shear adhesion strength of FMLs improved by 201.9 %, 133.9 %, and 91.4 %, respectively, compared to unmodified FMLs. When combining GNPs-modified PEEK with EPD, these properties increased further, with flexural strength, interfacial shear strength, and shear adhesion strength enhanced by 281.7 %, 238.7 %, and 112.4 %, respectively, compared to unmodified FMLs. Molecular dynamics simulations were performed to further investigate the role and mechanism of GNPs in the GNPs/PEEK/titanium ternary system. The simulations revealed that combining a GNPs-modified matrix with EPD significantly enhances the system's interfacial energy. Moreover, GNPs substantially influence the torsional behaviour of the PEEK main chain. These combined experimental and simulation results offer new insights into applying GNPs in composite materials.
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JOURNAL OF ELECTRONIC MATERIALS
·
2025
·
IF 2.5
Li Lingyu,Ma Qian,Zhao Dongheng,Zhang Huayushuo,Li Bolong
Recently, the development of an n-pentane-sensing product has always been plagued by the lack of suitable inorganic material with good gas-sensing response and selectivity at low operating temperatures. In this work, Ti-MIL-125-induced one-dimensional tubular In 2 O 3 /TiO 2 heterostructures have been fabricated by a facile electrospinning method and a subsequent heat-treatment process. Obvious morphological evolution from a fibrous to a tubular shape with the presence of In 2 O 3 -TiO 2 heterojunctions can be adjusted by varying the added amount of the Ti-ML-125 component. Compared with pure In 2 O 3 , the optimal In 2 O 3 /TiO 2 composites exhibit a blue-shifted energy band (2.52 eV) and an increased specific surface area (227.70 m 2 /g), as well as the enhanced gas-sensing performance on various concentrations of n-pentane. For example, In 2 O 3 /TiO 2 -3% can not only display excellent long-term stability and humidity stability but also has a high response of 670–100 ppm n-pentanol at 50°C, much larger than that of pure In 2 O 3 (50) at 150°C. Significantly, In 2 O 3 /TiO 2 -3% can still reach the high response of 197–100 ppm n-pentanol at room temperature. According to density functional theory (DFT) calculations, the enhanced gas-sensing mechanism is mainly attributed to the combination of the distinctly increased surface active sites through the regulation of morphology and the introduction of effective In 2 O 3 -TiO 2 heterojunctions, which can be beneficial to improving the surface adsorption/desorption characteristics and the electron transport between n-pentanol and the sensing material interface. Graphical
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Alexandria Engineering Journal
·
2025
·
IF 6.8
Wenliang Fan,Qinliang Gao,Yingying Yang,Ligang Wang,Yanlai Wang,Haiyan Yao
In order to discuss the intermediate band (IB) formation mechanism, influence on photoelectric conversion, electron transition process and other photovoltaic properties of Ti-doped p-CuGaS 2 light absorption material, p-CuGaS 2 and Ti-doped p-CuGaS 2 were synthesized through low-cost heat injection and annealing. Structural characterization results indicate that Ti 3 + partially replaced Ga 3+ in the Ti-doped p-CuGaS 2 . Two additional sub-band absorption peaks of Ti-doped p-CuGaS 2 confirm the formation of an IB. The band structures are confirmed by optical analysis and ultraviolet photoelectron spectroscopy, and the electron transition processes—from the valence band (VB) to the conduction band (CB), the valence band (VB) to the IB, and the IB to the conduction band (CB)—are analyzed. The IB formation mechanism is discussed using the band structure and theoretical calculations derived from density functional theory. A thin-film solar-cell model with Ti-doped p-CuGaS 2 as the absorbing layer is created. Numerical simulations based on experimental data show that the photoelectric conversion efficiency increase from 15.06 % for CuGaS 2 to 25.46 % for Ti-doped p-CuGaS 2 because of the IB effect, which enhances the optical absorption and extends the spectral response range. In conclusion, the research findings will establish a fundamental basis for the exploration of intermediate-band solar cells based on copper gallium sulfide.
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Nanoscale
·
2024
·Vol. 16
·期 22
·10727-10736
·
IF 5.8
Peijiao Chen,Zhijun Li,Pengze Wang,Yuxin Yao,Tianwei Dou,Yang Qu,Liqiang Jing
The photocatalytic water-mediated CO2 reduction reaction, which holds great promise for the conversion of CO2 into valuable chemicals, is often hindered by inefficient separation of photogenerated charges and a lack of suitable catalytic sites. Herein, we have developed a glycerol coordination assembly approach to precisely control the distribution of atomically dispersed Cu species by occupying Ti-defects and adjusting the ratio between Cu species and Ti-defects in a hierarchical TiO2. The optimal sample demonstrates a ∼4-fold improvement in CO2-to-CO conversion compared to normal TiO2 nanoparticles. The high activity could be attributed to the Ti defects, which enhance the photogenerated charge separation and simultaneously facilitate the adsorption of water molecules, thereby promoting the water oxidation reaction. Moreover, by means of in situ EPR and FTIR spectra, we have demonstrated that Cu species can effectively capture photogenerated electrons and facilitate the adsorption of CO2, so as to catalyze the reduction of CO2. This work provides a strategy for the construction of atomic-level synergistic catalytic sites and the utilization of in situ techniques to reveal the underlying mechanism.
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PubMed
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MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Chao Zhao,Jiayi Zhu,Xingye Ma,Jiaqi Sun,Ning Wang,Xi Chen,Xiaohan Chen,Yihao Wang,Chuanquan Wang,Xinyue Jing
Rapid and accurate pathogen detection is critical for optimizing clinical decision-making within precision medicine frameworks, specifically for identifying Staphylococcus aureus (S. aureus) in wound infections. Most of conventional detection methods suffer from procedural complexity, protracted analysis times, and insufficient sensitivity, thereby constraining their clinical deployment. In this work, an optical fiber surface plasmon resonance (SPR) sensor enhanced by Ti 3 C 2 T x MXene was developed for detecting S. aureus , biofunctionalized with goat anti-human immunoglobulin G (IgG). The optimal thickness of Ti 3 C 2 T x MXene layer, determined to be approximately 94 nm based on maximizing figure of merit (FOM) of 17.88 RIU −1 , yielded high sensitivity and low full width at half maximum (FWHM). By monitoring SPR wavelength shifts in the transmission spectra, the sensor was employed to detect S. aureus with a low limit of detection (LOD) of 1.14 CFU/mL and a high sensitivity of 3.063 nm/log (CFU/mL). It exhibited excellent linearity across the concentration range of 10 2 –10 8 CFU/mL, alongside high stability and selectivity. Validation using S. aureus -infected wound tissue from diabetic murine models exhibited a precision exceeding 97 %. This technology represents a promising avenue for developing next-generation, high-performance biosensing platforms with significant translational potential in precision medicine diagnostics.
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