Journal of Manufacturing Processes
·
2023
·
IF 6.2
Shuye Zhang,Jincheng Lin,Ce Wang,Peng He,Wei Wang,Xinfei Zhang,Tong Wu,Han Mei,Yue Liu,Panpan Lin,Tiesong Lin
The brazed joint of sapphire transparent ceramic and Kovar alloy was prepared using AgCuTi and AgCuTiB composite filler, and the main focus was the effect of B element on the wetting behavior, interface composition and joint mechanical performance. The reliable joint of sapphire transparent ceramic and Kovar alloy was obtained by vacuum brazing with AgCu28-6Ti-0.45B (wt%) composite filler. The typical interfacial structure of the joint brazed at 825 °C for 10 min was determined as sapphire/Ti 3 Cu 3 O/Ag(s,s) + Cu(s,s) + disperse TiB/TiFe 2 + TiNi 3 /Kovar. The results showed that the addition of B could contributed to an optimized interfacial structure via (i) in-situ forming fine TiB whisker reinforcement phase and refining the interface structure and (ii) reducing the diffusion degree of alloy side elements to inhibit the generation of brittle phase, and the maximum shear strength of the joint with AgCu28-6Ti-0.45B (wt%) reached 125 MPa more than twice the joint without B additive. On the other hand, the wetting experiment showed that the addition of B as a solid particle decreased the fluidity of the composite filler, and when the addition of B was excessive, no dense TiB whiskers were produced in the interface. This study provides ideas for the optimization and improvement of sapphire composite connection, and points out that the generation of reinforcing phase is accompanied by the reduction of fluidity, so it is necessary to reasonably control the proportion of reinforcing phase.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 15
·43702-43713
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IF 5.8
Guo Jin,Sun Yihua,Luo Qiuzi,Zhang Jiangyu,Fang Liang
Innovative solar-driven heterostructure photocatalysts are promising for removing the organic contaminants in the water environment. In this work, a sequence of well-defined Z-scheme Ti-Ga co-doped ZnO/g-C 3 N 4 (TGZ/CN) heterostructure photocatalysts were developed via a simple sol–gel method and the single-phase dispersion method in order to realize the cooperative improvement from the Ti/Ga co-doping and construction of heterostructure. The synthesized samples were analyzed by a variety of characterization techniques, and the photocatalytic activity was assessed by photodegradation of methylene blue (MB) under visible light irradiation. Compared to the ZnO and g-C 3 N 4 , the TGZ/CN composite demonstrated higher photocatalytic performance for the degradation of MB indicating an efficient photocatalytic degradation rate of 95.4% in 105 min under visible light. Moreover, the TGZ/CN photocatalyst exhibited excellent stability after five cycles of MB photodegradation. Furthermore, the as-prepared composites’ possible photocatalytic mechanism was discussed in detail. The improved photocatalytic performance primarily resulted from the effectively reduced band gap of ZnO after Ti/Ga co-doping and the facilitated separation of photoexcited e − /h + pairs caused by the construction of Z-scheme heterojunction. This work offers novel insights in developing hybrids with highly efficient photocatalytic activity towards future environmental applications. Graphical abstract
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高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2023
·Vol. 40
·期 12
·3059-3067
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IF 2.7
Yin Zihang,He Ruibo,Nie Fei,Wei Zhen,Jia Bo,Feng Qing,Fu Xiaolong,Zhang Wenyan
The oxygen evolution kinetics of industrial copper electrodeposition is slow, resulting in low electrocatalytic activity and high energy consumption. In this work, a quaternary composite of carbon coated active particles containing Mn, Co and Ce were prepared (Mn-Co 3 O 4 /CeO 2 @C), and Ti/Sb-SnO 2 /PbO 2 electrode doped with these active particles was prepared by co-electrodeposition. The microstructure and chemical composition of the electrode was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and Tafel polarization curve (Tafel) were used to study the electrochemical properties of anode materials. The results showed that the doping of Mn-Co 3 O 4 /CeO 2 @C active particles promoted the crystal transition of PbO 2 , decreased the average grain size, and the doping of Ce increases the average valence state of Co. The modified titanium electrode showed excellent catalytic activity of the oxygen evolution reaction (OER) characteristics. The overpotential of the doped Ti/Sb-SnO 2 /PbO 2 anode was only 453 mV when the current density was 20 mA cm −2 in 0.5 M H 2 SO 4 solution, which is 508 mV lower than that of the undoped Ti/Sb-SnO 2 /PbO 2 anode. In simulated copper electro-deposition experiments, the cell voltage was reduced by about 400 mV, compared to the undoped Ti/Sb-SnO 2 /PbO 2 electrode.
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Tao Xiang,Jie Chen,Weizong Bao,Shuyan Zhong,Peng Du,Guoqiang Xie
Stress shielding is caused by the mismatch of stiffness between bone and implant materials, which may give rise to bone resorption and loosening, thereby causing implantation failure. There is a huge gap between Young's modulus of human bone and low Young's modulus β Ti alloys. A porous structure design can achieve the target of low Young's modulus, and thus achieve the matching between human bone and implant materials. However, a suitable space holder (SH) that can be applied at high temperatures and sintering pressure has not been reported. In this study, the TiZrNbTa/Ti titanium matrix composite (TMC) with high strength and large ductility was used as scaffold materials and combined the SH technique with the spark plasma sintering (SPS) technique to obtain a porous structure. A novel space holder, i.e., MgO particles was adopted, which can withstand high-temperature sintering accompanied by a sintering pressure. The porous TiZrNbTa/Ti with 40 vol.% MgO added exhibits a maximum strength of 345.9 ± 10.4 MPa and Young's modulus of 24.72 ± 0.20 GPa, respectively. It possesses higher strength compared with human bone and matches Young's modulus of human bone, which exhibits great potential for clinical application.
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NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 31
·14828-14839
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IF 3.3
Lin Dong,Yunlan Xu,Dengjie Zhong,Nianbing Zhong,Zhuofan Han,Yi Liu,Haixing Chang
The low electron–hole separation in the photoanode generally restricts the visible light response of photocatalytic fuel cell (PFCs). In this study, 5% NH2-MIL-125/g-C3N4/Bi2O3/Ti photoanode was synthesized and assembled with a PFC with Cu cathode to degrade rhodamine B and generate electricity. With visible light irritation, the maximum photocurrent density, maximum power density, and degradation rate of the PFC were 0.59 mA cm−2, 29.88 μW cm−2, and 97.48% (1 h), respectively. The major active species in the PFC were h+, ˙O2−, and ˙OH. The good performance of the PFC was ascribed to the formation of a double Z-type heterojunction in the 5% NH2-MIL-125/g-C3N4/Bi2O3/Ti photoanode so that the photoelectrons of NH2-MIL-125 and Bi2O3 directly combine with the photoholes of g-C3N4, making the photoholes of NH2-MIL-125 and Bi2O3 and the photoelectrons of g-C3N4 directly or indirectly involved in the RhB degradation process and generating electricity. Thus, the separation rate of the e−–h+ pairs in the photoanode and the capability of the PFC are greatly improved.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2022
·
IF 4.804
Chen Chao,Mo Peicheng,Chen Jiarong,Hu Xixi,Hu Qiaofan,Lin Feng,Wu Yi
Using TiN-Ti-AlN as the binder, polycrystalline cubic boron nitride (PCBN) composites containing Y 2 O 3 and not containing Y 2 O 3 were prepared under high temperature and ultra-high pressure conditions, respectively. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to analyze the phase composition, microstructure and surface crack morphology of the composite material. At the same time, the compactness, microhardness and bending strength of the composite material were tested. The research results show that the phase composition of PCBN sample is mainly composed of BN, TiB 2 , TiN, AlN and Y 2 O 3 at an ultra-high pressure of 5.5 GPa and a temperature of 1500 °C. With the increase of Y 2 O 3 content, the relative density of PCBN first increases and then decreases, and the changes in mechanical properties also tend to be similar. As the content of Y 2 O 3 increases, it can be seen that the peak intensity of the main peak of TiB 2 also increases, indicating that the addition of Y 2 O 3 promotes the reaction between cBN and Ti. When the Y 2 O 3 content is 3.6%, PCBN has the best comprehensive mechanical properties, with a microhardness of 34.56 GPa and a bending strength of 890 MPa.
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JOURNAL OF ELECTRONIC MATERIALS
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2022
·Vol. 51
·期 11
·6121-6133
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IF 2.047
Mou Jiaxin,Xu Yunlan,Zhong Dengjie,Chang Haixing,Xu Chunzi,Wang Hui,Shen Hongyu
In order to enhance the photoelectric conversion efficiency of a photoanode and broaden its light absorption range, a ZnIn 2 S 4 /UiO-66/TiO 2 /Ti composite photoanode was developed. The maximum photocurrent density of the prepared photoanode is 2.56 mA cm −2 at 1.2 V (versus SCE), which is 1.79 times higher than that of ZnIn 2 S 4 /TiO 2 /Ti. The rhodamine B (RhB) removal rate, short-circuit current density and maximum power density of a photocatalytic fuel cell (PFC) constructed with the ZnIn 2 S 4 /UiO-66/TiO 2 /Ti photoanode and a Cu cathode are 98.01%, 0.22 mA cm −2 and 16.97 μW cm −2 respectively. The enhancement of the PFC performance is mainly attributed to the extremely good energy band matching and nano-size interface contact between ZnIn 2 S 4 and UiO-66. The existence of UiO-66 can be as an electronic transmission bridge, which not only facilitates the rapid transfer and utilization of photogenerated electrons, but also improves the adsorption ability of the photoanode for RhB molecules. Graphical Abstract
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JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Wen Xu,Xiaoshu Wang,Weilong Hou,Kang Tang,Xinqing Lu,Yijing Gao,Rui Ma,Yanghe Fu,Weidong Zhu
Although the titanosilicate zeolite catalyzed one-pot oxidative hydration of ethylene with hydrogen peroxide (H 2 O 2 ) to ethylene glycol (EG) takes advantages of step-saving and facile operation, both H 2 O 2 utilization efficiency and EG yield are relatively low. In the present work, Sn-doped Ti-MWW zeolites, named Sn-Ti-MWW, were developed for this oxidative hydration, showing the much higher H 2 O 2 utilization efficiency and EG yield, compared to Ti-MWW. The extensive characterizations of Sn-Ti-MWW zeolites, in combination with Density Functional Theory (DFT) calculations, verify that the doping of Sn into Ti-MWW leads to the higher electropositivity of the Ti species, resulting in the stronger acidity of the zeolite, which is helpful to the H 2 O 2 utilization and EG production. In addition, although the catalyst deactivation is observed due to the deposition of the bulky byproducts onto the active sites and/or into the zeolite micropores, the simple calcination of the used catalyst readily restores its catalytic activity. Therefore, it is anticipated that the developed Sn-Ti-MWW catalyst might be applicable in the one-pot oxidative hydration of ethylene with H 2 O 2 to EG industrially.
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CHEMOSPHERE
·
2023
·
IF 8.8
Hoang Nguyen Tien,Fredrick M. Mwazighe
In this work, a novel La-doped βPbO 2 (Ti/SnO 2 –Sb/La-βPbO 2 ) was prepared using electrodeposition method and applied to the degradation of prednisolone (PRD), 8-Hydroxyquinoline (8-HQ), and other typical organic pollutants. Compared with the conventional electrode Ti/SnO 2 –Sb/βPbO 2 , La 2 O 3 doping enhanced oxygen evolution potential (OEP), reactive surface area, stability and repeatability of the electrode. The 10 g L −1 of La 2 O 3 doping exhibited the highest electrochemical oxidation capability of the electrode with [•OH]ss being determined at 5.6 × 10 −13 M. The quenching experiments were conducted to confirm the main oxidizing species (here: •OH) in the electrochemical process. The study showed that the pollutants were removed in the electrochemical (EC) process with different degradation rates and indicated that the second-order rate constant of organic pollutants towards •OH ( k OP,•OH ) has a linear relationship with the degradation rate of organic pollutants ( k OP ) in the electrochemical process. Another new finding in this work is that a regression line of k OP,•OH and k OP can be used to estimate k OP,•OH of an organic chemical, which cannot be determined using the competition method. k PRD,•OH and k 8-HQ,•OH were determined to be 7.4 × 10 9 M −1 s −1 and (4.6–5.5) × 10 9 M −1 s −1 , respectively. Compared with conventional supporting electrolyte (like SO 4 2− ), H 2 PO 4 − and HPO 4 2− improved k PRD and k 8-HQ by 1.3–1.6-fold, while SO 3 2− and HCO 3 − inhibited k PRD and k 8-HQ significantly, down to 80%. Additionally, the degradation pathway of 8-HQ was proposed based on the detection of intermediates from GC-MS.
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高影响因子
Crystals
·
2023
·Vol. 14
·期 1
·14
·
IF 2.7
Yufei Zu,Zi Wang,Hongliang Tian,Fan Wu,Lianshen Fu,Jixiang Dai,Jianjun Sha
High-entropy diboride-based (MeB2-based) ceramics are promising high-temperature structural materials because of their excellent mechanical properties, high-temperature stability, and oxidation resistance. In order to achieve low-temperature sintering of the high-entropy ceramics, a novel preparation method of high-entropy (Ti,Zr,Nb,Mo,W)B2-SiC ceramics based on reactive sintering of pre-alloyed solid-solution metals and nonmetals of Si, C, B4C was conducted in the current work. Mechanical alloying behavior of the mixed metal powders, as well as the phase composition, microstructure, mechanical properties, and oxidation behavior of the as-sintered MeB2-SiC ceramic were investigated. The XRD, SEM, and EPMA results indicated that the primary MeB2solid-solution and SiC phases could be successfully formed during reactive sintering at a relatively low temperature of 1650 °C. The as-sintered MeB2-SiC ceramics had a high relative density of 97.8% and high mechanical properties (hardness of 19.74 ± 0.8 GPa, flexure strength of 533 ± 38 MPa, and fracture toughness of 6.01 ± 0.77 MPa·m1/2). Combining the oxidation behavior and microstructure evolution of the oxidation layer, a continuous and relatively dense MeOx-SiO2oxidation layer was gradually formed and covered on the external surface, leading to decelerating oxidation behavior after an oxidation exposure time of 10 min.
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OPTICAL MATERIALS
·
2023
·
IF 3.9
Yuwei Sun,Xin Qi,Chou Chen,Wenyu Liu,Qian Tang,Honghui Teng,Baixiang Ren
In this work, AgI nanoparticles were anchored on decahedron-like MIL-125(Ti) through wet precipitation method, and the photocatalytic activities were analyzed by tetracycline (TC) degradation rates under simulated sunlight. The structures, morphologies, valence bonds, optical absorption properties, charge separation efficiencies of the prepared samples were tested by XRD , SEM, EDS , XPS, UV–Vis DRS and PL spectroscopy. Compared with pure MIL-125(Ti), AgI@MIL-125(Ti) displayed excellent photocatalytic performance on TC degradation. When the mass fraction of AgI in AgI@MIL-125(Ti) was 10 %, AgI@MIL-125(Ti)-10 % displayed the best photocatalytic efficiency, which 96.9 % of TC was removed under simulated sunlight for 30 min. The results of active species trapping experiments and ESR tests showed that the Z-Scheme heterojunction between AgI and MIL-125(Ti) promoted the separation of photogenerated charges. Furthermore, a part of Ag + were reduced to Ag NPs in the process of photocatalytic reaction, which constructed a cross-linking bridge for the charges at the interface of AgI and MIL-125(Ti) and further accelerated the electron transmission. The intermediate toxicity experiments proved that the toxic structures are destroyed in TC solution after MIL-125(Ti)-10 % photocatalytic degradation, and the toxicity of the reaction system was reduced effectively.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Yue Wei,Gang Li,Cong Wang,Hongchen Guo
For solvent-free catalytic oxidations , low efficiency resulted from poor mass transfer and insufficient utilization of active centers remains a tough problem. Herein, we demonstrate a novel hybrid core-shell catalyst (TS@PMO) with an amphiphilic shell and a Ti-surface-enriched mesoporous TiO 2 -SiO 2 (TS) core to address this challenge. Such TS@PMO realizes its amphiphilicity via an ex situ formed periodic mesoporous organosilica (PMO) shell. Simultaneously, by a unique etching effect induced by organic precursor growth on [SiO 4 ] tetrahedra in TS core, active Ti sites are facilely enriched in near-surface layer of core and extra mesoporous cavities are introduced for substrate reservation. When applied for solvent-free epoxidation of methyl oleate (MO) with H 2 O 2 , TS@PMO exhibits remarkably boosted catalytic activity (X = 90.2%) and epoxide selectivity (S = 70.2%), overwhelming the unmodified titanosilicate (X = 63.7%, S = 49.2%) and Ti-containing organosilica (X = 39.8%, S = 25.0%). Such result benefits from an evidently enhanced interphase mass transfer and sufficiently accessible active Ti sites in TS@PMO. On the one hand, amphiphilic PMO shell can efficiently collect hydrophobic substrate and H 2 O 2 , while abundant mesopores in the shell offer open-path for them to access active sites in the core; on the other hand, an increased framework Ti (IV) density and their surface-enrichment in TS core greatly improve the utilization of active Ti sites. This study effectively makes up for the deficiencies of slow mass transfer and insufficient utilization of conventional titanosilicates in biphasic reactions, which paves a new avenue to exploit other hybrid catalysts for high-efficiency solvent-free catalysis.
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