查找使用阿拉丁产品的科研文献

PVDF-based energetic films with high output performance: Synergistic effect based on Al/Ti

Lejian Chen,Xianghong Xiao,Haofang Yuan,Hongyu Chen,Yuxuan Zhou,Yinghua Ye,RuiQi Shen,Lizhi Wu

With the ongoing advancement of miniaturization and microfabrication, Micro-Electro-Mechanical Systems (MEMS) energetic devices are increasingly demanding higher output capabilities from energetic materials. This study investigates the incorporation of Titanium (Ti) into PVDF-based energetic films to improve their performance. We fabricated five Al/Ti/CuO/PVDF energetic composite films with varying Ti contents by direct ink writing (DIW). The results indicate that the Al/Ti/CuO/PVDF films demonstrate superior performance compared to Al/CuO/PVDF(AT-0). Notably, the 50 wt% Al/50 wt% Ti/CuO/PVDF (AT-50) film achieved optimal performance, exhibiting a 68% increase in combustion rate compared to the AT-0 film. Additionally, it showed a reduction in ignition delay time by 6 ms, an increase in flame temperature of 160.9 K, a 24% rise in maximum pressure, a pressurization rate enhancement of 117%, and an overall increase in heat release of 26.8%. This is attributed to the synergistic effect of the Al/Ti bimetallic fuels, where their close contact creates an alloying reaction that releases a large amount of heat and avoids the detrimental effects of Al sintering. This Al/Ti/CuO/PVDF energetic composite film, characterized by its exceptional synergistic mechanism and high energy output, holds significant promise for integration with MEMS devices, paving the way for innovative applications in micro-ignition, micro-propulsion, and micro-startup technologies. Highlights Ti was added to the PVDF-based energetic films to form the dual-fuel system. The Al/Ti dual-fuel has a synergistic effect to improve output performance. The 50wt%Al/50wt%Ti/CuO/PVDF film can achieve optimal output performance.

Characterization and properties of polypyrrole modified ZnIn2S4/TiO2/Ti photoanode in photocatalytic fuel cell

Yunlan Xu,Jiaxin Mou,Lin Dong,Qingmei Qiao,Dengjie Zhong

The performance of photocatalytic fuel cell (PFC) depends on photoanode, which is the key to generate photoexcited carriers and degrade organic wastes. In this study, ZnIn 2 S 4 nano-bandgap semiconductor and polypyrrole were used to modify TiO 2 to prepare polypyrrole/ZnIn 2 S 4 /TiO 2 /Ti photoanode to increase its photo-response range and the separation of photoexcited carriers. The PFC with polypyrrole/ZnIn 2 S 4 /TiO 2 /Ti photoanode and copper cathode was built to degrade RhB and generate electricity. The RhB removal rate, open-circuit voltage, short-circuit current density, and maximum power density of the photocatalytic fuel cell were 94.6 % (1 h), 0.47 V, 0.23 mA cm −2 and 21.11 μW cm −2 , respectively. The improvement of PFC performance is attributed to the good visible-light responsive properties of polypyrrole/ZnIn 2 S 4 .The presence of polypyrrole acts as both an electron donor and a hole acceptor, which provides an ideal pathway for the separation and transmission of photogenerated carriers. The synergistic effect of polypyrrole, ZnIn 2 S 4 and TiO 2 eventually increases the photocatalytic ability of the PFC. This research can offer reference for the study of TiO 2 -based efficient visible light responsive PFC.

Decomposition Behavior and Strengthening Mechanism of Ti-TiO2 Material in Selective Laser Melting Process

Xiang Hongliang,Chen Xiaoyu,Huang Ye,Wu Chaochao,Mou Gang,Zheng Kaikui

This study investigated the fabrication of a strengthened Ti-TiO 2 material with adding 0.5 wt.% TiO 2 nanoparticles via selective laser melting process in comparison with CP-Ti. Through the process parameters optimized by response surface methodology, the Ti-TiO 2 material fabricated by SLM showed remarkable tensile strength of 800.6 MPa and elongation of 14%, as compared to the fabricated CP-Ti with tensile strength of 594.0 MPa and elongation of 21%. The x-ray diffraction patterns of fabricated specimens showed the expansion of the hcp -Ti lattice along the c -axis due to dissolved oxygen atoms from the decomposition of TiO 2 nanoparticles. The microstructure analysis observed remains of incompletely decomposed TiO 2 and TiO phases in SLMed Ti-TiO 2 material, which was distinguished from former studies. Consequently, the decomposition behavior of added TiO 2 nanoparticles associated with the dissolved oxygen in the Ti-matrix during the SLM process was discussed. Based on the evaluation of both the solution effect of oxygen atoms and the reinforcing effect of undecomposed nanoparticles, the dissolved oxygen from decomposed TiO 2 was considered the primary factor in the intensified strength of SLMed Ti-TiO 2 material. These results could offer novel insights into the additive manufacturing of high-strength and biocompatible titanium alloy via the SLM process.

Molecular Hydrogen Chemisorbed on Unsaturated Coordinate Ti: A New Designed Materials for Hydrogen Storage

Chengguang Lang,Lei Zhang,Cheng-Jie Yang,Hanwu Dong,Hao Zhong,Chung-Li Dong,Jun Chen,Aijun Du,Yi Jia,Liuzhang Ouyang,Xiangdong Yao

Solid-state hydrogen storage materials with optimal binding energy are essential for hydrogen storage and transportation applications and pose long-standing challenges. Current technologies, including molecular physisorption materials (e.g., metal–organic frameworks (MOFs), carbon nanotubes (CNTs), activated carbons (ACs)) and atomic chemisorption materials (e.g., MgH 2 , LiBH 4 , NH 4 BH 4 ), fall short of meeting practical application requirements. Therefore, designing and constructing new solid-state hydrogen storage materials at the atomic level is critically important. In this study, the use of defect engineering is explored to modulate hydrogen adsorption sites on TiO 2 surfaces. The results demonstrate that low-coordinated titanium (Ti) atoms on TiO 2 can serve as effective hydrogen adsorption sites, storing hydrogen through molecular chemisorption with significantly enhanced adsorption energy compared to Ti atoms in high coordination states. Moreover, the adsorbed hydrogen remains in molecular form, facilitating easy desorption at room temperature, unlike titanium hydride, which requires high temperatures for desorption. This approach provides a promising pathway for developing efficient hydrogen storage materials by leveraging the unique properties of low-coordinated Ti atoms on TiO 2 surfaces.

The enhanced photocatalytic activity of TiO2(B)/MIL-100(Fe) composite via Fe–O clusters

Tao Wang,Xiqing Liu,Mei Liu,Runhua Liao,Hongquan Zhan,Xiaoxue Qi,Yongqing Wang,Yanju Huang

Black TiO2 and metal–organic frameworks (MOF) are great materials with light-harvesting ability, redox power and consequently catalytic activity. Here, the integration of MIL-100(Fe) with TiO2(B) composite was designed for photocatalytic application, which greatly promoted light-harvesting and charge transfer. As expected, the integrated TiO2(B)/MIL-100(Fe) composite showed high photocatalytic activity due to unique Fe–O–Ti bonds that were constructed, which acted as an electronic tunnel to reduce electronic transfer resistance between MIL-100(Fe) and TiO2(B). In addition, the presence of Fe–O clusters in MIL-100(Fe) can also promote the charge dissociation and improve catalytic activity via the Fe3+/Fe2+ redox cycle. This achievement would help us to understand and design charge transfer pathways in the integration of MOF/semiconductor photocatalysts.

Active Site Regulation on Mo/Ti Catalysts for the Direct Dehydrogenation of Fluoroalkanes to Fluoroalkenes

Wucan Liu,Junxing Wang,Xiang Sun,Ming Cheng,Jiamin Jin,Dang-Guo Cheng,Fengqiu Chen

Vinylidene fluoride (VDF) is a fundamental fluorinated olefin in the fluorochemical industry, and innovation in its production holds significant importance for sustainable development. Traditional routes involving the dehydrohalogenation or dehalogenation of halogenated alkanes suffer from issues such as substantial waste emissions and severe equipment corrosion. The one-step catalytic dehydrogenation of 1,1-difluoroethane (HFC-152a) to produce VDF offers notable advantages. To accomplish this goal, this work innovatively aims to construct an oxidative dehydrogenation system with a highly dispersed Mo/Ti catalyst for HFC-152a. Through systematic characterization techniques, such as XPS, XRD, Raman spectroscopy, and TPD, the reaction mechanism is thoroughly investigated. These results prove that more abundant O2– species are related to improved activity, achieving 21.1% VDF selectivity and modest stability for at least 20 h.

Highly Sensitive Surface Plasmon Resonance Sensor Modified With 2D Ti₂C MXene for Solution Detection

Shuaiwen Gan,Banxian Ruan,Yuanjiang Xiang,Xiaoyu Dai

Pd-Ni/Cd loaded PPy/Ti composite electrode: Synthesis, characterization, and application for hydrogen storage

Xiaoyang Wan,Xuefeng Wei,Juan Miao,Ruichang Zhang,Jun Zhang,Qingshan Jason Niu

Summary A wide compositional range of Pd-Ni/Cd on polypyrrole (PPy)-modified Ti plates (Pd-Ni/Cd/PPy/Ti) was fabricated via electrochemical deposition. The hydrogen absorption properties of the prepared Pd-Ni/Cd/PPy/Ti electrodes were evaluated using cyclic voltammetry and chronoamperometry in acidic media. The optimal Pd 36 -Ni 7 /Cd 57 /PPy/Ti electrode achieved a hydrogen storage capacity of 331.3 mC cm −2 mg −1 and an H/Pd ratio of 0.77. The enhancement of the hydrogen storage was attributed to a synergistic effect between the Pd-Ni/Cd catalysts. The surface morphology, crystallinity, and chemical composition of the Pd-Ni/Cd/PPy/Ti electrode were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. Hydrogen spillover occurred on the trimetallic catalysts, and secondary hydrogen spillover occurred on the PPy/Ti support. The enhanced hydrogen sorption capacity was due to both the synergistic effect of the trimetallic catalysts and the assistance of PPy, making Pd-Ni/Cd/PPy/Ti a promising hydrogen storage material.

Preparation of NCh-B and NCh-B-Ti nanocomposites and their ignition and combustion performances

Yu-shu Xiong,Yong-qi Wang,Chong Wan,Wen-zhen Zhang,Zhao Qin,Su-hang Chen,Kang-zhen Xu

To overcome the agglomeration and insufficient combustion of nano-boron (n-B) powders, this study successfully prepared two novel types of boron-based nanocomposites using the acoustic resonance technology, namely high-substitute nitrochitosan/nano-boron (NCh-B) with ratios of 1:3, 1:5, 1:7 and 1:9, and nitrochitosan/nano-boron powder/nano-titanium (NCh-B-Ti) with Ti contents of 5 wt%, 10 wt%, 15 wt% and 20 wt%. The structural morphologies, laser ignition and combustion properties of the composites were systematically investigated. The results suggest that the addition of NCh can significantly improve the dispersion of n-B. NCh-B exhibited a higher combustion performance than n-B, as evidenced by their ignition delay and flame areas. When the laser power density was 81 W, NCh-B 5 -Ti 15% exhibited a combustion time and an ignition delay of 240 ms and 5.5 ms respectively, which were higher and lower than those of NCh-B 5 (199 ms and 17 ms, respectively). Furthermore, NCh-B 5 -Ti 15% displayed a lower ignition delay than both n-B powders (12 ms) and NCh-B (11 ms), as well as brighter flames and a larger combustion area. Therefore, the addition of n-Ti can promote the combustion of n-B powders, with the combustion products of NCh-B-Ti including H 3 BO 3 , B 2 O 3 , TiB 2 , and TiO. This study provides a new method for improving the ignition performance and combustion efficiency of n-B powders.

Electron impact excitation of allowed and forbidden transitions between fine-structure levels in Ti III

Yang Wang,Qiuyao Cao,Xi-Ming Zhu,Chun-Meng Du,Klaus Bartschat

Abstract. Introduction: We present an extensive theoretical investigation of the electron impact excitation of doubly-ionized titanium (Ti III) to meet the needs of spectral analysis and plasma modeling. OBJECTIVES: The main objective of this work is to extend the currently scarce database of both structure and collision data for Ti III. METHODS: The calculation was performed in the close-coupling approximation using the B-spline R-matrix method. The multi-configuration Hartree–Fock method in combination with B-spline configuration interaction expansions and the non-orthogonal orbitals technique is employed for accurate descriptions of the target wave functions and adequate accounts of the various interactions between the target states. Relativistic effects are treated at the semi-relativistic Breit-Pauli approximation level. RESULTS: The present close-coupling expansion includes 138 fine-structure levels of Ti III belonging to the 3d2, 4s2, 4s4p, 3d4l (l=0-3), 3d5l (l=0-3), 3d6s, and 3d6p configurations. Comprehensive sets of radiative and electron collisional data are reported for all of the possible transitions between the 138 fine-structure levels. Thermally averaged collision strengths are determined using a Maxwellian distribution for a wide range of temperatures from 102 K to 105 K. The accuracy of the calculated radiative parameters is validated by comparing with available values from the NIST database and previous literature. CONCLUSION: Given the lack of sufficient currently available experimental and theoretical data, the electron impact excitation cross sections of the Ti III fine-structure levels presented here are systematic, extensive, and internally consistent, thus making them suitable for many modeling applications.

Fabrication of highly dispersed Ti/ZnO–Cr2O3 composite as highly efficient photocatalyst for naphthalene degradation

Shengjie Xia,Lianyang Zhang,Xiaobo Zhou,Mengmeng Shao,Guoxiang Pan,Zheming Ni

In this paper, Ti-contained Schiff base complex was intercalated into the interlayer of the ZnCr layered double hydroxides (LDHs) to form a novel layered organic–inorganic nanoscale material. And then, the hybrid material was further calcined to make metal oxides composite contained Zn, Cr and Ti (Ti/ZnO–Cr 2 O 3 ). This composite was used to study the performance and mechanism for naphthalene ( l -acid) photodegradation under visible light. The characterization results showed that Ti/ZnO–Cr 2 O 3 composite has higher specific area, more uniform pores size distribution and narrower band gap than that of original ZnCr–LDHs. Both physico-chemical property and photocatalytic performance for l -acid degradation by Ti/ZnO–Cr 2 O 3 were greatly improved with the increasing of calcination temperature, due to the highly crystalline structures with appearance of spinel ingredients of Zn, Cr and Ti. In addition, the molar ratio of Ti/Cr would also influence the photocatalytic property of the materials. Ti/ZnO–Cr 2 O 3 composite with Ti/Cr   =   1 and calcined at 800   °C not only has narrow bang gap (2.11   eV) and high surface area (227   m 2 ), but also shows highest photocatalytic performance for l -acid degradation (90.2% within 240   min). Furthermore, the types and amounts of active radicals of photo oxidation reaction were also tested. The photocatalytic mechanism of the Ti/ZnO–Cr 2 O 3 composite was also discussed. Moreover, based on the results from HPLC–MS, GC–MS, FT–IT and DFT analysis, the decomposition intermediates and reaction pathway for l -acid were investigated in detail.

Biofunctionalization of carbon nanotubes/chitosan hybrids on Ti implants by atom layer deposited ZnO nanostructures

Yizhou Zhu,Xiangmei Liu,Kelvin W.K. Yeung,Paul K. Chu,Shuilin Wu

One-dimensional (1D) nanostructures of ZnO using atomic layer deposition (ALD) on chitosan (CS) modified carbon nanotubes (CNTs) were first introduced onto the surfaces of biomedical implants. When the content of ZnO is not sufficient, CNTs can strengthen the antibacterial activity against E. coli and S. aureus by 8% and 39%, respectively. CS can improve the cytocompatibility of CNTs and ZnO. The amount of Zn content can be controlled by changing the cycling numbers of ALD processes. This hybrid coating can not only endow medical implants with high self-antibacterial efficacy against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) of over 73% and 98%, respectively, but also regulate the proliferation and osteogenic differentiation of osteoblasts by controlling the amount of ZnO.