Crystals
·
2023
·Vol. 13
·期 7
·1005
·
IF 2.7
Zhiwei Liu,Guanlong Li,Yan Zhao,Xiangbao Chen
The rapid development of electronic technology has brought convenience and efficiency to the lives of modern people, while emphasizing the need for novel materials with designability and excellent dielectric properties at the same time. In this work, Ti3C2TxMXene nanosheets (MNSs) underwent NH3·H2O solvothermal treatment at temperatures of 40 °C, 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 160 °C, and 180 °C. The changes in the surface groups and dielectric properties after the solvothermal treatment were studied. The solvothermal treatment increased the proportion of surface -OH groups, which was beneficial to the permittivity of the MNSs. However, as the treating temperature increased, the amount of -OH on the surface of the MNSs showed a reducing trend, according to XPS spectra. As the treating temperature rose from 40 °C to 80 °C, the real part of the permittivity of MNS sample showed a significant decrease, eventually remaining approximately stable in the 80 °C to 180 °C samples. The results of electromagnetic characterization were in line with the group proportion, as determined via the XPS O1s spectra, supporting the previous conclusion that the -OH group played an important role in the permittivity.Keywords:NH3·H2O solvothermal;end groups;dielectric property;2D nanosheets
研究领域:
材料科学
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纳米技术
·
电子学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Refrigeration
·
2021
·
IF 3.629
Zhenghao Jin,Shuhong Li,Runfa Zhou,Mengkai Xu,Weixue Jiang,Kai Du
The newly NH 3 – H 2 O – LiBr working fluid can decrease the power wasted in the generator, thus improves the COP of the ammonia absorption refrigeration system. But the applying of NH 3 – H 2 O – LiBr working fluid decreases the ammonia absorption efficiency, so the COP of the system is still unsatisfactory. To further enhance the COP of the NH 3 – H 2 O - LiBr absorption refrigeration system, TiO 2 nanoparticles are added to the NH 3 – H 2 O - LiBr working fluid in this study. And the effects of TiO 2 nanoparticles concentration on the performances of the generator, absorber, evaporator, condenser, and solution heat exchanger are tested in an ARS experimental system. The experimental results indicate that the addition of TiO 2 nanoparticles increases the P g , P e , P a , and P c , meaning that the value of ammonia produced in the generator increases. Therefore, the COP and iCOP of the system are improved by adding TiO 2 nanoparticles, and the COP is maximum improved by 18.96% compared with the ammonia-water absorption refrigeration system. When the x TiO2 is increased from 0.3% to 0.5%, the increase rate of the COP decreases because the newly added nanoparticles do not disperse well. So 0.3% is a better choice for the TiO 2 nanoparticles concentration when comprehensively considering the dispersion stability of nanoparticles and the COP.
研究领域:
工程热物理
·
制冷技术
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2024
·
IF 4.5
Yu Zhu,Bihe Yuan,Zhezhe Tan,Zeyang Gao,Man Yang,Sining Chen
NH 3 ·H 2 O can result in severe accidents when leaking in a confined space. In this work, a novel powder-water mist synergistic strategy for decontaminating NH 3 ·H 2 O in a confined space is proposed. Initially, FeCl 3 /AlCl 3 was employed to modify diatomite, decorating its pore structure and augmenting the number of acidic adsorption sites. The modified diatomite achieves a notable efficiency of 74.6%, surpassing that of the raw diatomite (43.8%). Subsequently, surfactants were introduced to increase the contact area between the water mist and NH 3 , while a thickening agent was employed to suppress the fluidity of NH 3 ·H 2 O. Ultimately, the powder-water mist synergistic decontamination system was constructed by integrating the diatomite with a thickening agent and water mist containing surfactants. The synergistic system exhibits a superior decontamination efficiency of approximately 80%. This work generates fresh insight into decontaminating NH 3 ·H 2 O in a confined space and offers a crucial avenue for future advancements in decontamination technology.
研究领域:
环境科学
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2025
·
IF 4.7
Lei-ting SHEN,Yu LIU,Juan-lang GUO,Qiu-sheng ZHOU,Tian-gui QI,Zhi-hong PENG,Gui-hua LIU,Xiao-bin LI
The leaching of sulfuric acid converted product of scheelite in NH 3 ·H 2 O−NH 4 HCO 3 solution was systemically studied to improve sulfuric acid conversion−ammonium salts leaching technology route for ammonium paratungstate production. The results showed that the WO 3 leaching efficiency was about 99% under optimal conditions of 350 r/min, liquid-to-solid ratio of 3 mL/g, 1 mol/L NH 4 HCO 3 , 4 mol/L NH 3 ·H 2 O, 25 °C, and 15 min. During the leaching, CaSO 4 almost had no change and was still in a banding or rod-like shape in short leaching time, while conglobate CaCO 3 was gradually formed on the CaSO 4 surface. A secondary reaction might occur between CaSO 4 and WO 4 2− , which could be restrained by a certain amount of CO 3 2− in the solution. There was no CaCO 3 phase determined by XRD in leaching residue of converted product for scheelite concentrate under optimal conditions, which was different from that for synthetic scheelite. The leaching process could be explained by neutralization reaction of H 2 WO 4 and solid transformation of CaSO 4 in NH 3 ·H 2 O−NH 4 HCO 3 solution.
研究领域:
冶金化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2022
·
IF 6.465
Zhenghao Jin,Shuhong Li,Runfa Zhou,Mengkai Xu,Weixue Jiang,Kai Du
Adding nanoparticles can enhance the mass and heat transfer of basic fluid, improving the coefficient of performance(COP) of the absorption refrigeration system(ARS). However, there are few experimental studies on the effects of absorption pressure and temperature on the absorption performance of nanofluid in an actual ARS. Therefore, the TiO 2 nanoparticles are added to the NH 3 - H 2 O – LiBr working fluid. The difference in ammonia mass fraction between the inlet and outlet solution of the absorber (Δ ε ' a ) is compared with when the solution is absorbed saturated (Δ ε a ). The results indicate that the Δ ε ' a and system COP increase when the absorption temperature decreases, the absorption pressure increases, or the TiO 2 mass fraction increases. The ratio Δ ε ' a /Δ ε a is used to evaluate the absorption efficiency of the nanofluid. The positive effects of nanofluid on the absorption efficiency and COP slightly increase when absorption temperature increases, but decrease when the absorption pressure is greater than 0.31 MPa. For all of our test groups, the greatest improvement in absorption efficiency is 85 %, and the largest improvement in COP is 13.7 %.
研究领域:
热力学
·
制冷工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2020
·
IF 7.635
Beibei Ma,Rijia Lin,Hui He,Qinghua Wu,Shuixia Chen
Hydrothermal is common process for synthesizing well-ordered mesoporous silica, however, it costs time and energy simultaneously. To improve the efficiency of synthesis process, it is necessary to propose a facile synthesis strategy with less time and energy requirement. In this study, an innovative non-hydrothermal method using NH 3 ∙H 2 O as catalyst after ripening step is developed to prepare SBA-15 with short mesochannels (SSBA-15) for the first time. The synthesis period of SSBA-15 framework was extremely shortened within 40 min under the optimized conditions (30 min of ripening step and 25% of NH 3 ∙H 2 O concentration), while obtained material exhibits well-ordered hexagonal pore structure and fine particle morphology of SSBA-15 (pore length of 250 ± 50 nm and mesopore size of 9.8 nm). This method can also be employed to synthesize conventional SBA-15 successfully. Moreover, the application of SSBA-15 as support of solid amine adsorbents on CO 2 adsorption and well-fitting of experimental CO 2 adsorption data with Avrami and intraparticle diffusion models reveal that the adsorbents combine the advantages of micro-mesoporous structure, short mesochannel and amine reagents (high affinity of CO 2 ), resulting in enhanced molecular diffusion, fast adsorption kinetics and high CO 2 adsorption capacity . Notably, the solid amine adsorbents exhibited excellent regeneration ability during ten adsorption-desorption cycles. This work opens up new opportunities in efficient preparation of materials that require hydrothermal process.
研究领域:
材料科学
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环境工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2026
·
IF 9.1
Kunlin Li,Wei Guo,Yu Tian,Kai Li,Ping Ning,Xueyan Chen,Fei Wang,Changbin Zhang
Carbon-based materials are widely used for H 2 S oxidation, yet their performance under ambient conditions requires further improvement via precise structural engineering. In particular, existing MgO-modified carbon materials still suffer from suboptimal H 2 S removal capacity, limited regenerability, and/or complicated synthesis processes, which restrict their practical application in room-temperature desulfurization. In this work, we report MgO/N-doped carbon catalysts synthesized by an NH 3 ·H 2 O-modulated citric acid complexation method, which demonstrated superior activity for ambient H 2 S oxidation. It was shown that the introduction of NH 3 ·H 2 O induced the formation of NH 4 NO 3 in pyrolysis precursors, and the decomposition of NH 4 NO 3 during pyrolysis created abundant carbon defects and also incorporated pyridinic/pyrrolic N species. These defects anchor Mg ions, leading to the formation of well-dispersed MgO nanosheets that enhanced surface basicity and facilitated H 2 S dissociation. Meanwhile, the defect-rich structure significantly improved O 2 activation to generate reactive 1 O 2 species for efficient H 2 S oxidation. The optimized MNC-3 delivered an exceptional H₂S capacity of 2.41 g/g cat. with 55 h breakthrough time at room temperature, and retained 0.78 g/g cat. after three regeneration cycles. This work provides a rational design strategy for high-performance, cost-effective room-temperature desulfurization materials through integrated modulation of active phase morphology, nitrogen doping, and carbon defects.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Yue Yin,Xian Luo,Benjun Xu
Li 4 Ti 5 O 12 (LTO) is the most promising anode material for lithium-ion batteries owing to its excellent cycle stability and safety. However, the electrochemical performance of LTO at high rates is limited by its low conductivity. Generally, LTO preparation requires organic titanium sources, which are expensive. In this study, inexpensive H 2 TiO 3 was used as the titanium source, LiOH‧H 2 O served as the lithium source, and NH 3 ‧H 2 O was added to control the pH of the solution. Simple one-step liquid-phase deposition and calcination were performed for obtaining in situ self-assembled LTO submicron spheres with stable morphology and excellent electrochemical performance. According to electrochemical performance tests, the sample calcined with 4 mL of 25% NH 3 ‧H 2 O at 700 °C (LTO-4–700) exhibited the best performance. Its discharge capacity remained at 176.4 mAh g −1 over 100 cycles at 87.5 mA g −1 and retained at 136.7 mAh g −1 over 500 cycles at 875 mA g −1 , and its specific capacity was 105.6 mAh g −1 over 1000 cycles, even at a current of 1750 mA g −1 with a retention rate of 96.7%. Furthermore, LTO-4–700 exhibited excellent rate performance at 3500 mA g −1 compared to other samples. Cyclic voltammetry and electrochemical impedance spectroscopy confirmed that submicron spherical LTO-4–700 had a high Li + migration rate and low electrochemical impedance.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2019
·Vol. 15
·期 17
·1805478
·
IF 10.856
Kai Jia,Jiahua Ye,Guoxin Zhuang,Zanyong Zhuang,Yan Yu
Fabrication of low-dimensional nano-MOFs as well as nanoparticles/metal-organic frameworks (MOFs) hybrids has sparked new scientific interests but remains a challenging task. Taking Cu 3 (BTC) 2 as a proof of concept, it is demonstrated thats NH 3 ⋅H 2 O solution of a confined pH value can readily shape the bulk Cu 3 (BTC) 2 into nanoscale Cu 3 (BTC) 2 , beyond the need to control the crystal growth kinetics of MOFs. Adjusting the pH of NH 3 ⋅H 2 O within a much small range (10–11) allows fine tuning over the size and shape of nanoscale Cu 3 (BTC) 2 . Particularly at pH = 11, NH 3 ⋅H 2 O exhibits weak reducibility that triggers a reduction of part of Cu 3 (BTC) 2 into Cu 2 O, while shaping the other into Cu 3 (BTC) 2 nanowires. Benefiting from the coincidence of reduction and etching effects, the newly generated Cu 2 O dots can in situ anchor onto adjacent Cu 3 (BTC) 2 nanowires at highly dispersive state, forming a well-defined sponge-like architecture built of Cu 2 O dots and nano-Cu 3 (BTC) 2 . The CuO x derived from annealing of the Cu 2 O dots/nano-Cu 3 (BTC) 2 hybrid preserves the sophisticated sponge architecture and high porosity, and exhibits promising applications in phenol scavenging, with efficiency outperforming its counterparts and many other Cu-based catalysts reported in literature. It is anticipated that the findings here pave the way for the rational design of intricate nano-MOFs in a more efficient way.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）