CATALYSIS TODAY
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2022
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IF 6.562
Xinchao Liu,Huan Liu,Lihua Chen,Baolian Su,Xinhuan Lu,Qinghua Xia,Dan Zhou
Herein, highly efficient Ti-containing zeolite catalyst (Ti/Al-HSZ) has been prepared by an active catalysis species surface implanting strategy (ACS-SIS) through the combination of precedent acid treatment and subsequent recrystallization. Compared with commercial titanosilicate zeolite catalysts and Ti-HSZ catalyst synthesized by one-step method, Ti/Al-HSZ- c - 3.5d-AT catalyst presents highly enhanced catalytic activity and turnover number values in the epoxidation of linear and cycloalkenes by using 30% H 2 O 2 as oxygen agent under mild reaction conditions. Particularly for the conversion of bulky linear alkene and cycloalkene (1-dodecene and cycloheptene), the catalytic activity of Ti/Al-HSZ- 4M‐3.5d‐AT can attained more than three times than that over Ti-HSZ- 3.5d-AT . Based on systematical comparison and analysis, on one hand, the excellent catalytic performance of Ti/Al-HSZ is ascribed to its unique hollownest morphology that acts as ideal reaction space by providing with plenty of hierarchical porous structure and high external surface, which is beneficial for the diffusion and mass transfer of bulky substrate. On the other hand, the high content of active open Ti species locating on the surface of catalyst is particularly beneficial for the formation of transition state to accelerate the epoxidation reaction. Not only the Ti source utilization rate but also the Ti open incorporated rate of Ti/Al-HSZ- 4M‐3.5d‐AT prepared by ACS-SIS is much higher than that of Ti-HSZ prepared by one-step hydrothermal synthesis route. The effects of acid treatment and recrystallization on the zeolite framework, morphology, chemical composition, and Ti coordination states have been thoroughly discussed. The ACS-SIS is believed to be an effective route to construct excellent solid heterogeneous catalyst to meet the urgent need of green chemistry for sustainable development.
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TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
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2022
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IF 3.752
Xue-yi GUO,Zhao-wang DONG,Yang XIA,Pei-dong LIU,Han-ning LIU,Qing-hua TIAN
A high-purity Ti–48Al–2Nb–2Cr alloy powder with an oxygen content as low as 0.0572 wt.% and a particle size of <150 μm was produced from a mixture of TiO 2 , Al 2 O 3 , Nb 2 O 5 , and Cr 2 O 3 powders through reduction with magnesium and deoxidation with calcium. The phase and composition of the products were analyzed. The final product mainly included γ -TiAl and minor α 2 -Ti 3 Al phases, and Ti, Al, Cr, and Nb were homogenously distributed in the powder with a mole ratio of 49.73:43.51:2.05:1.98. The reduction and deoxidation mechanisms were investigated by thermodynamic modeling using the HSC Chemistry software and Pandat software based on the Ti alloy database.
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Materials
·
2022
·Vol. 15
·期 3
·793
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IF 3.748
Hai Tang,Yuhao Zhou,Wenjie Yuan
To investigate the action mechanism of titanium, the effects of different Ti-bearing compounds, including CaTiO3, MgTiO3, and nano-TiO2, on the properties of alumina–magnesia castables were studied. By analyzing the phase compositions, microstructures, and physical and mechanical properties of the castables, it was demonstrated that an intermediate product, CaTiO3, was first generated. This was then consumed by solid-solution reactions, and titanium was involved in the liquid formation as the temperature increased. The solid-solution reaction of CA6(CaAl12O19) was more prominent due to the incorporation of more titanium in the crystal lattice of CA6instead of spinel (MgAl2O4). Moreover, the liquid formation was strongly promoted when more titanium accompanied the calcium, which finally accelerated the densification and improved the strengths of alumina–magnesia castables. On the whole, castables with CaTiO3addition presented higher bulk density and excellent strength after the heat treatment. Besides, the castables with 2 wt.% CaTiO3contents were estimated to possess greater thermal shock resistance.Keywords:Ti-bearing compounds;CA6;spinel;castables
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PubMed
高影响因子
Catalysts
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2023
·Vol. 13
·期 5
·915
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IF 3.9
Xiaofeng Yu,Chunjie Shi,Yueling Cheng,Yejing Zhu,Renyuan Song,Shengfei Hu
Methyl benzoate (MB) compounds are prepared by reacting various benzoic acids with methanol using an acidic catalyst. In this study, the solid acids of zirconium metal solids fixed with various substances were studied. We determined that zirconium metal catalysts with fixed Ti had the best activity. The catalytic synthesis of a series of MB compounds using titanium zirconium solid acids was studied. The direct condensation of benzoic acid and methanol using a metallic Lewis acid without other auxiliary Bronsted acids is reported for the first time.Keywords:methyl benzoate;solid acid;catalysis
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JOURNAL OF ALLOYS AND COMPOUNDS
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2023
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IF 6.2
Hao Tu,Huihu Wang,Huang Xu,Ziguan Zhang,Guode Chen,Chenhuinan Wei,Xing Xiang,Zhixiong Xie
In this work, a series of ZnIn 2 S 4 nanosheets encapsulated NH 2 -MIL-125(Ti) heterostructures (NM-125(Ti)@ZIS) have been rationally designed and established through a facile oil bath method. The photocatalytic Cr(VI) reduction and H 2 evolution performance on NM-125(Ti)@ZIS were elaborately modulated by adjusting the mass ratio of two components, introducing S vacancy and loading cocatalysts. The experimental results demonstrate that the optimized NM-125(Ti)@ZIS heterostructure with mass ratio 3:1 of NM-125(Ti) to ZIS has an excellent Cr(VI) reduction performance in neutral solution, giving 98% reduction efficiency within 60 min. Moreover, the NM-125(Ti)@ZIS heterostructure, following the introduction of sulfur vacancies and the incorporation of Pt nanoclusters , demonstrates an optimal visible light (λ > 420 nm) hydrogen evolution rate of 4.708 mmol/g/h, which is 5.82 times greater than that of pristine ZIS. A thorough investigation of the microstructures and photoelectrochemical properties of the NM-125(Ti)@ZIS heterostructures reveals that the intimate contact interface, sulfur vacancy, and Pt nanocluster serve to effectively enhance charge separation efficiency, thereby improving the photocatalytic performance. Further analysis on the charges behavior at the interface verifies that a novel Z-scheme heterojunction has been constructed between ZnIn 2 S 4 and NH 2 -MIL-125(Ti).
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Haiying Xu,Zhaoliang Wang,Hehua Liao,Dongmiao Li,Jinni Shen,Jinlin Long,Wenxin Dai,Xuxu Wang,Zizhong Zhang
Photocatalytic converting CO 2 into C 2 products is highly desirable but is extremely sensitive to catalyst structure. In this work, Ti-H species and oxygen vacancies are simultaneously integrated on hydrogenated SrTiO 3 surface by thermally treating with NaBH 4 , which promotes the activation of CO 2 into HCOO - and CO* intermediates. The proximity of oxygen vacancies and Ti-H species contributes to the C-C coupling of intermediates into acetylene (C 2 H 2 ) products. To the best of our knowledge, this is the first example for the photocatalytic CO 2 reduction into C 2 H 2 main products. The optimal hydrogenated SrTiO 3 has the C 2 H 2 yield of 39.0 μmol·g −1 with a 76.0 % selectivity among C 2 products. Therefore, this work provides an approach of designing the adjacent active sites for photocatalytic CO 2 conversion into C 2+ products.
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CHEMICAL ENGINEERING JOURNAL
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2023
·
IF 15.1
Ming Zhou,Xiao Ma,Cuiyue Ji,Lekai Zhao,Jiahao Chen,Yongdong Shi,Delong Liu,Zhaoxiang Zhong,Ze-Xian Low,Weihong Xing
Creating adsorbents that exhibit high selectivity towards pollutants, can be readily regenerated, and maintain high stability, remains a crucial challenge in water treatment technology. Herein, we present a magnetically and chemically recoverable absorbent based on Ti and Co co-substituted LaFeO 3 (La 0.9 Fe 0.55 Ti 0.3 Co 0.15 O 3 , LFTCO) with significantly enhanced adsorption properties. Notably, LFTCO exhibits a methyl blue adsorption capacity (q max ) of 2131 mg/g, setting a new record among perovskite oxides, due to the increased surface oxygen vacancy with the dual doping strategy. The selected dual-dopant consists of Fenton active Co and spin-state interactive Ti, which allows creating more oxygen vacancy and simultaneously facilitating pragmatic regeneration of the adsorbent. The new LFTCO exhibits significantly enhanced ferromagnetism (M = 7.27 emu/g), enabling rapid magnetic separation from water and subsequent Fenton-based regeneration step. We also reveal that the anchored configuration of SO 3 -defect site, through density functional theory (DFT) calculation, as the most favorable site for the adsorption process. These findings provide a pathway to creating high-performance adsorbents and shed light on the mechanistic understanding of LFTCO's enhanced adsorption properties.
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Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Zi-Ying Zeng,Dong-Dong Zhou,Shu-Tong Yang,Miao-Miao Su,Zhong-Hua Yang
This work synthesized a novel adsorbent by doping COF and MIL-125(Ti) in the nanoparticles Fe 3 O 4 . The obtained results showed that the doping of COF and MIL-125(Ti) had a positive effect on enhancing the specific surface area and adsorption capacity. Moreover, the adsorption process has been confirmed to follow the Langmuir model and pseudo-second-order kinetic, and the maximum adsorption capacity for tetracycline and tebuconazole was 138.1 mg/g and 87.73 mg/g, respectively. Finally, the adsorbent displayed an excellent adsorption performance in three kinds of actual environmental water samples. The mechanics of the adsorption process mainly involved π-π stacking interaction, hydrogen-bonding interaction, electrostatic interaction, and complexation interaction. In short, the synthesized magnetic adsorbent displayed a good application potential for removing tetracycline and tebuconazole from wastewater.
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JOURNAL OF MATERIALS SCIENCE
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2023
·Vol. 58
·期 38
·15035-15046
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IF 4.5
Wang Xiongwei,Ma Rui-Juan,Guo Tingyu,Zhang Xuewei,Wang Hui,Zhao Xu
Abstract The hydrogen iodide decomposition reaction of the sulfur-iodine (SI) cycle is realized by electrolysis at room temperature to achieve efficient hydrogen production, while iodine is recycled throughout the SI reaction. In this work, we report a facile hydrothermal method for the synthesis of sulfur-doped titanium dioxide (S- \(\hbox {TiO}_2\) ) nanosheets with evenly distributed on the Ti foil (S- \(\hbox {TiO}_2\) /Ti). The noble metal-free S- \(\hbox {TiO}_2\) /Ti electrode demonstrates excellent electrochemical catalytic performance for iodine evolution reaction. It can deliver a high current density of 100 mA/ \(\hbox {cm}^2\) with a potential of 1.05 V, which is close to 90% of that of precious metal platinum and 5.6 times of bare Ti foil. Furthermore, the S- \(\hbox {TiO}_2\) /Ti electrode is stable in a mixed acid solution of HI and \(\hbox {H}_2\hbox {SO}_4\) . Compared to \(\hbox {TiO}_2\) /Ti, diffuse reflectance spectroscopy and ultraviolet photoelectron spectroscopy analysis evidence a reduction in the band gap and work function of S- \(\hbox {TiO}_2\) /Ti due to the doping of sulfur. Correspondingly, the current efficiency approaches to 100% under the electrolysis constant voltage 1.30 V. Eventually, the detailed mechanism to describe the improvement of the electrocatalytic performance was suggested. Graphical abstract
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Catalysis Science & Technology
·
2023
·Vol. 13
·期 22
·6561-6569
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IF 5
Songlei Mo,Yong Guo,Xiaohui Liu,Yanqin Wang
The glycolysis of polyethylene terephthalate (PET) is considered as the most promising PET recycling strategy due to its mild reaction conditions and circularity. Herein, several metal-doped SBA-15 (M/SBA-15) as heterogeneous Lewis acid catalysts were investigated to screen the best catalyst and to understand the essence for their differences in PET glycolysis. It is found that the catalytic activity is positively correlated with the acid amount in different metal-doped SBA-15 and Ti/SBA-15 with different Ti loadings, with the exception of Nb/SBA-15. 4Ti/SBA-15 with abundant Lewis acid sites shows excellent PET glycolysis ability, with the yield of bis(2-hydroxyethyl) terephthalate (BHET) reaching 87.2% within 45 min at 190 °C (isolated yield 73%). While 4Nb/SBA-15 has a similar acid amount as that in 4Ti/SBA-15, but it has very low catalytic activity probably due to its strong oxygen affinity. Acetone–methanol-adsorption DRIFTS confirms its strong oxygen affinity, which would poison the acid sites by ethylene glycol (EG) and result in very low activity. This study demonstrates that PET glycolysis activity is really correlated with the amount of Lewis acid sites, but species with very strong oxygen affinity would lower its activity. Further diffuse reflection ultraviolet-visible (DR UV-vis) spectra analysis confirms that tetrahedral Ti4+ species in Ti/SBA-15 is the real active center. In addition, 4Ti/SBA-15 has good reusability and can be used in common real PET (dyed polyester fabric, PET bottles) glycolysis. These results indicate that increasing the amount of Lewis acid sites is a promising way to enhance PET glycolysis and 4Ti/SBA-15 with high activity and stability is a potential catalyst for industrial application.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhangyi Huang,Zhengwei Zhu,Mingyu Su,Yang Shi,Mao Deng,Ruichong Chen,Zhijun Wang,Zhi Zhou,Jianqi Qi,Haomin Wang
This study investigated the high-temperature oxidation behaviors of TMC ceramics. The results indicate that the high-temperature oxidation curves of the four TMC ceramics follow a parabolic law, suggesting a diffusion-controlled process. The activation energies for the oxidation of TaC, NbC, TiC, and ZrC ceramics are 105.4, 124.3, 169.3, and 78.7 kJ/mol, respectively, with oxidation rate constants at 1000 °C of 16.84, 40.45, 0.18, and 14.43 mg 2 /cm 4 ·h for each ceramic, respectively. The temperatures at which the ceramics disintegrate into fragments in high-temperature air are 800, 800, >1000, and 600 °C, respectively. The anti-oxidation performance of the four TMC ceramics ranks as follows: TiC > TaC > NbC > ZrC. In comparison to the reported high-entropy carbide ceramics, the TiC ceramic in this study demonstrates superior anti-oxidation performance due to dense TiO 2 layer formation, characterized by significantly low oxidation rates and excellent structural stability.
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高影响因子
POLYHEDRON
·
2020
·
IF 2.343
Zhongmin Liu,Cong Wang,Yongchuan Wu,Longlong Geng,Xiuling Zhang,Dashuai Zhang,Hui Hu,Yongzheng Zhang,Xin Li,Wei Liu,Ping Na
The adsorption behavior of arsenic on adsorbent have been researched widely, but chemical adsorption of arsenic is uncommon. In this work, a kind of microporous metal-organic framework (MIL-125(Ti)) with columnar morphology and uniform size was solvothermally synthesized, and its chemical adsorption behavior and mechanism of arsenic were firstly investigated by experimental and simulation study. Remarkably, ultra-fast adsorption behavior and excellent arsenic removal capability was achieved. It takes only 20 min to rapidly remove 5 mg L −1 arsenic with 0.2 g L −1 MIL-125(Ti), which is far superior to the previously reported materials. Both experimental and simulation study results show that the adsorption of arsenic obeys a new chemical adsorption mechanism. Both As(III) and As(V) can easily replace the terephthalic acid ligand via competitive coordination and bind to the Ti active site of MIL-125(Ti). In addition, the reaction energy barriers for ligand substitution by H 2 O, As(III) and As(V) are 0.46, 0.33 and 0.15 eV, respectively, which further confirming that structure reforming of MIL-125(Ti) plays a key role for chemical adsorption. The study solves the difficulty of removing low concentration of arsenic and provides molecular-level understanding of the chemical adsorption mechanism of arsenic on MIL-125(Ti).
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