JOURNAL OF RARE EARTHS
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2023
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IF 4.9
Falin Zhang,Xiaoying Liang,Rongfei Wei,Hai Guo,Fangfang Hu
In this work, a group of Bi 3+ /Eu 3+ -doped SiO 2 –Al 2 O 3 -MCO 3 (M = Ca, Sr, Ba) glasses were fabricated through melt-quenching method. Their structure and photoluminescence characters were studied via X-ray diffraction (XRD), UV–Vis transmission spectra (TRS), excitation spectra, emission spectra and decay lifetimes. The XRD results show that no nano-crystal phase forms in glass matrix with different doping concentrations of Bi 3+ and Eu 3+ ions. Through regulating optical alkalinity value, the intensity of Bi 3+ ions increases and the peak position shifts to red wavelength. The Bi 3+ /Eu 3+ co-doped glasses show a blue-white-yellow-red luminescence by changing concentration of Eu 3+ ions. Energy transfer efficiency from Bi 3+ to Eu 3+ can reach as high as 10.54%. At 423 K, the emission intensity of 55SiO 2 –10Al 2 O 3 –35BaO-0.25Bi 2 O 3 (GBE0.5) is 31.1% of that at 308 K. Meanwhile, the activation energy of the glass matrix is 0.251 eV. All results suggest that these Bi 3+ /Eu 3+ co-doped glass samples possess potential application in LED field.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
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IF 4.326
Yuxi Gao,Baofang Jin,Zhenyu Xi,Zhenguo Li,Xiaodong Wu,Rui Ran,Zhichun Si,Duan Weng
Silver-based catalysts are promising candidates for soot oxidation because of their good catalytic performances and low costs compared with platinum catalysts. NO2 acts as a strong agent for the oxidation of soot over Pt/Al2O3. However, an abnormal inhibition effect of NOx was observed over the Ag/Al2O3 catalyst during the processes of soot temperature-programmed oxidation and transient reaction analysis. The formation of silver nitrates was confirmed by temperature-programmed decomposition of NOx, ultraviolet–visible spectroscopy, and temperature-programmed reduction with H2. The intrinsic reactivity of silver nitrate was found to be much lower than that of metallic silver in ″loose″ and ″tight″ contacts between soot and catalyst. Moreover, the formed silver nitrate was relatively thermally stable, with the decomposition completed at around 450 °C. At higher temperatures, the catalyst recovered and the nitrate poisoning effect no longer worked.
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Journal of Water Process Engineering
·
2023
·
IF 7
Longxiang Xia,Jing Shen,Dengfeng Wu
Herein, Al 2 O 3 supported ultra-small Mn-CeOx nanoparticles (Mn-CeOx/Al 2 O 3 ) are prepared by a facile impregnation method for removal of phenolic compounds via catalytic ozonation . Mn and Ce species are in the form of polyvalent oxide nanoparticles with an average size of 0.9 nm. The removal efficiency of total organic carbon for phenol-containing model wastewater by Mn-CeOx/Al 2 O 3 shows a volcano relationship by changing the mass ratio of Mn and Ce, and reaches up to the peak value when the mass ratio is 5:5. The cycle stability tests suggest the removal efficiency of Mn-CeOx/Al 2 O 3 could maintain at 90.16 % after 5 circles. The enhanced performance should be attributed to the optimized magnetism and accelerated charge transfer by composition regulation. The magnetic strength changing affects the adsorption mode of O 3 , while the redox cycle of Mn(IV)/Mn(III) and Ce(IV)/Ce(III) could enhance the activation of O 3 to produce more ·OH and 1 O 2 for the organic molecules mineralization.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
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IF 5.7
Weichao Wang,Liuying Wang,Gu Liu,Chaoqun Ge,Long Wang,Bin Wang,Jie Huang
Ti 3 SiC 2 exhibits considerable potential for high-temperature microwave absorption due to its relatively high melting point and conductivity. In this study, we successfully prepared Ti 3 SiC 2 /Al 2 O 3 -13%TiO 2 heterogeneous coatings through granulation and plasma spraying techniques. This investigation covered composition, microstructure, oxidation resistance, and a focused analysis of the temperature-dependent permittivity of the coatings. The augmentation in Ti 3 SiC 2 content leads to an escalation in the polarized component, consequently elevating susceptibility to dielectric dispersion. With rising temperature, polarization within the coatings gradually establishes, prompting a transition from polarization relaxation loss to conduction loss as the dominant dielectric loss mechanism. At 5 wt% Ti 3 SiC 2 content, the coating achieves an effective bandwidth of 2.2 GHz at 873 K, with a mere 1.4 mm thickness. Moreover, the coating maintains exceptional oxidation resistance below 700 °C. Ti 3 SiC 2 /Al 2 O 3 -13%TiO 2 coatings manifest as strong contenders for high-temperature microwave absorption applications, and plasma spraying emerges as a promising technique for fabricating high-performance microwave absorption coatings.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Weichao Wang,Gu Liu,Liuying Wang,Chaoqun Ge,Long Wang,Bin Wang,Jie Huang
The advancement of absorption materials and coating preparation technology is crucial to address the challenges posed by electromagnetic interference and pollution in high-temperature extreme environments. Here, by using a granulation and plasma spraying strategy, we successfully fabricated a series of La 0.8 Sr 0.2 MnO 3 /Al 2 O 3 –13%TiO 2 (LSMO/AT13) high-temperature microwave absorption coatings that have excellent dielectric properties and extremely thermal stability. The results showed that the LSMO/AT13 coatings exhibited remarkable oxidation resistance , withstanding high-temperature aerobic environments of up to 1000 °C. Based on the temperature-dependent permittivity of the coatings, the establishment process of polarization and the transformation of loss mechanism were observed and explained. With the increase of temperature, the main dielectric loss mechanism of the coatings transitions from polarization loss to conductive loss. Thanks to the coordinated effects of impedance and loss, the coatings are capable of effectively absorbing microwave over a wide temperature range. When the LSMO content was 30 wt% and the thickness was 1.9 mm, the effective bandwidth ranged from 1.7 GHz to 2.4 GHz at temperatures below 773 K. This study demonstrates the promising application of LSMO/AT13 microwave absorption coatings for ultra-high temperature environment, and provides a reference for the design and optimization of high-temperature microwave absorption coatings.
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Surfaces and Interfaces
·
2023
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IF 6.2
Zixuan Zhao,Can Zou,E Zhou,Qing Liu,Kai Chen,Xingfu Wang,Longfei He,Fangliang Gao,Shuti Li
Interface engineering is an effective way to improve the performance of graphene-based photodetectors . Here, a graphene/GaAs heterojunction photodetector is fabricated, and when inserting an Al 2 O 3 tunneling layer, its performance is improved through direct tunneling (DT) and Fowler-Nordheim tunneling (FNT). According to the experimental results, it is found that the thickness of the tunneling layer has a great influence on the performance of the photodetector. Compared with graphene/GaAs photodetector, the performance of graphene/Al 2 O 3 (2 nm)/GaAs photodetector is significantly improved with the responsivity, detectivity, and external quantum efficiency value of 0.80 A/W, 3.02 × 10 11 Jones and 306% under 1 mW/cm 2 light intensity at 2 V bias. Meanwhile, fast response is also observed (rise/decay time of 3 ms/8.6 ms). The improvement of the photodetector's performance in this work is mainly attributed to the effective modification of the interface state by the Al 2 O 3 tunneling layer and the effect of the two tunneling mechanisms based on DT and FNT.
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JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
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2023
·Vol. 34
·期 7
·987-991
·
IF 1.4
Su Xiao-Ping,Zhao Le,Wang Xiang-Tong,Wang Zhao,Wang Zhi-Chao,Shen Tao,Zhang Ping
Different Al2O3 carriers were synthesized by co-precipitation and sol-gel method. From them, 4%NiO-20%MoO3/Al2O3 catalysts were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction analysis (XRD), N2 adsorption-desorption, NH3 temperature programmed desorption (TPD) and H2-temperature programmed reduction (TPR) and subsequently used for selective hydrogenation of naphthalene to high-value tetralin. The results showed that Ni-Mo/so-ge Al2O3 (900) exhibited better catalytic performance than Ni Mo/commercial Al2O3, achieving 99.56% naphthalene conversion and 99.43% tetralin selectivity.
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ACS Sustainable Chemistry & Engineering
·
2023
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IF 8.4
Sijie Li,Yuan Xue,Yixi Lin,Bing Wang,Xi Gao
Plastic recycling through thermochemical conversion for the production of fuels and chemicals is a promising way for simultaneous waste processing and utilization. In the current study, high-density polyethylene (HDPE) was subjected to pyrolysis and then catalytic upgrading to produce hydrogen in the presence of a novel Fe2O3/Al2O3 catalyst with a grain boundary. To understand the catalyst–support interaction as well as the resulting synergistic catalytic effects, catalytic pyrolysis of HDPE with supported Fe2O3/Al2O3 was compared with those over Fe2O3, Al2O3, and a cascade combination of both. It was found that the performance of Fe2O3/Al2O3 was superior to that of other catalysts in terms of chain cracking and C–C/C–H bond cleavage. The hydrogen yield with Fe2O3/Al2O3 was 50.53 mmol·gplastic–1, equivalent to more than 70% of hydrogen in plastic. Besides, alkanes/alkenes ranging from C2 to C9 dominated the hydrocarbon products. The analysis of the cycle performance revealed that the reduction pathway of Fe2O3/Al2O3 was different from those of other Fe2O3-containing catalysts, which was also confirmed by temperature-programmed reduction. To investigate the essential role and reaction mechanism with Fe2O3/Al2O3, characterizations of Fe2O3/Al2O3 before and after the reaction were conducted. The grain boundary between Fe2O3 and Al2O3 enhanced the adsorption of gaseous products. More importantly, the catalyst–support interaction to form FeAl2O4 during the pyrolysis reaction, determined by X-ray photoelectron spectroscopy, was responsible for effective proton adsorption and C–H bond cleavage. This study provides an insightful understanding of catalyst transformation during plastic catalytic pyrolysis for hydrogen production.
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FUEL PROCESSING TECHNOLOGY
·
2023
·
IF 7.5
Fa-Peng Wu,Yun-Peng Zhao,Zong-Pin Fu,Le-Le Qiu,Jian Xiao,Jian Li,Fang-Jing Liu,Jing-Pei Cao
Efficient transfer hydrogenolysis of benzyl phenyl ether (BPE) was accomplished over Ni 1.5 Cu 1.5 /Al 2 O 3 using isopropanol as hydrogen source . The characterization results demonstrated that the formation of NiCu alloy and electron transfer between Ni and Cu were responsible for the excellent catalytic performance. Isopropanol displayed better hydrogen-donating ability than other low-carbon alcohols because of its unique dehydrogenation pathway and small steric hindrance . The results of isotopic experiments elucidated that active hydrogen species for the C O bond cleavage originated from isopropanol rather than H 2 , while both isopropanol and H 2 were responsible for hydrogenation of phenol to cyclohexanol when reaction was conducted with mixed hydrogen sources. A mechanism study illustrated that transfer hydrogenolysis of BPE proceeded through direct cleavage of C O bond followed by phenol hydrogenation, in which the active hydrogen species were in the form of H + and H − .
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JOURNAL OF ALLOYS AND COMPOUNDS
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2023
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IF 6.2
Xiaolei Sun,Meiyi Jing,Hong Dong,Wenhe Xie,Feng Luo
Transition metal oxides are said to have the ability to enhance the gravimetric capacity of lithium-ion batteries by two or three times that of current state-of-the-art graphite anodes. Recent reports have demonstrated that the combined utilization of structural architecture and surface modification is an attractive strategy to improve lithium storage capability. In this study, novel CuO-ZnO@Al 2 O 3 submicroflakes were prepared by magnetron sputtering deposition of Cu-Zn alloy films on a removable sacrificial substrate, followed by a facile thermal oxidation treatment and Al 2 O 3 coating procedure by particle atomic layer deposition. They combine the advantages of CuO-ZnO submicroflakes, such as high lithium storage capability and fast lithium ion transportation, and Al 2 O 3 nano-coating with effective protection of the electrode interface during cycling. When utilized as anode materials for LIBs, the CuO-ZnO@Al 2 O 3 submicroflakes exhibit superior specific capacity, enhanced cycling stability, and outstanding rate capability compared with pristine CuO-ZnO submicroflakes, commercial CuO and ZnO powders. The CuO-ZnO@Al 2 O 3 submicroflakes electrodes deliver a high reversible capacity of 814 mAh g −1 at a current density of 50 mA g −1 , and still maintain a moderate capacity of 447 mAh g −1 at a high current density of 1000 mA g −1 . Pairing with a commercial LiFePO 4 cathode, full cell shows high capacity retention and stable cycling performance, suggesting the feasibility of the CuO-ZnO@Al 2 O 3 submicroflakes in practical energy storage applications. In addition, our findings also provide a clear proof-of-concept of the surface coating technique, which might be applied widely to other materials and devices where nano-coating produces desirable properties.
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Small
·
2023
·Vol. 19
·期 31
·2207046
·
IF 13.3
Dong Lu,Ke Lu,Hong-Tao Wen,Zhan Wei,Alberto Bianco,Gui-Gen Wang,Hua-Yu Zhang
The preparation of room temperature phosphorescent carbon dots still faces great challenges, especially in the case of carbon dots endowed of visible-light excitable room temperature phosphorescence (RTP). To date, a limited number of substrates have been exploited to synthesize room temperature phosphorescent carbon dots, and most of them can emit RTP only in solid state. Here, the synthesis of a composite obtained from the calcination of green carbon dots (g-CDs) blended with aluminum hydroxide (Al(OH) 3 ) is reported. The resultant hybrid material g-CDs@Al 2 O 3 exhibits blue fluorescence and green RTP emissions in an on/off switch process at 365 nm. Notably, this composite manifests strong resistance to extreme acid and basic conditions up to 30 days of treatment. The dense structure of Al 2 O 3 formed by calcination contributes to the phosphorescent emission of g-CDs. Surprisingly, g-CDs@Al 2 O 3 can also emit yellow RTP under irradiation with white light. The multicolor emissions can be employed for anti-counterfeiting and information encryption. This work provides a straightforward approach to produce room temperature phosphorescent carbon dots for a wide range of applications.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xueqin Zhang,Qiaoyu Meng,Keqiang Zhang,Rongqi Zhu,Zhaoliang Qu,Ying Li,Rujie He
Ceramics are attractive for structural components because of their excellent load-bearing capacity. Nevertheless, inferior energy-absorbing ability and poor reliability under common quasi-static and dynamic environments, especially under cyclic loading, extremely limit the popularization of ceramic components. The coupling between cellular structures inspired by the light but strong porous trabeculae and core–shell structure in strong and tough natural materials provides a solution for strengthening the load-bearing capacity, energy absorption ability, and cyclic life of ceramic components. Here, we proposed a bioinspired cellular ceramic structure/polyurea (CCS/polyurea) dual-phase architecture via additive manufacturing and simple infiltration technologies. It was demonstrated that the specific load-bearing capacity and energy-absorbing ability of bioinspired CCS/polyurea dual-phase architecture under quasi-static compressive loading were 2.22 and 50.34 times of CCS, respectively. Significantly, it could be repeatedly loaded at 40.28 and 48.82 MPa for over 120 and 8 cycles, respectively. Furthermore, CCS/polyurea dual-phase architecture performed extraordinary cyclic life under dynamic loading. The cyclic lives of CCS/polyurea dual-phase architecture at impact speeds of ∼ 6 and ∼ 12 m/s reached as high as 11 and 2, respectively. This research provides a credible approach to building ceramic-based materials with extraordinary load-bearing capacity, energy absorption ability, and especially remarkable cyclic life.
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