Journal of Electrochemical Science and Technology
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2024
·Vol. 15
·期 3
·353-364
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IF 2.2
Baikai Zhang,Xiaohui Li,Maochang Liu
Through component regulation and morphological construction, it is of considerable significance to develop high-activity and high-stability electrocatalyst for hydrogen evolution in electrolytic water. In the hydrothermal process, Mo-doped nickel-based sulfide catalysts (Mo-NiS-Fx) with a variety of morphologies (prisms, rods, flakes, and cones) were created by adding NH4F with varying masses. Among these, the flaky Mo-NiS-F1.2 exhibited exceptional performance towards electrochemical hydrogen evolution reaction, surpassing most similar catalysts with an overpotential of 79 mV at 10 mA cm-2 and a Tafel slope of 49.8 mV dec-1. Significantly, Mo-NiS-F1.2 maintained its high activity for hydrogen evolution over 60 h at a current density of 10 mA cm-2, making it suitable for widespread commercial application. According to the experimental findings, an electrocatalyst with a high surface area and a porous structure is better suited to exposing more gas transfer routes and active sites, which would encourage the hydrogen evolution reaction. This study presents a straightforward procedure for creating electrocatalysts with a range of morphologies, which can serve as a model for the creation of catalysts for use in industrial manufacturing.
研究领域:
材料科学
·
电化学
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DOI
高影响因子
Silicon
·
2026
·
IF 3.3
Idowu Peter Babatunde,Wang Xiaohui,Ma Shuhua,Oduye Temitope Gabriel
A new process for the controlled-synthesis of large surface area mesoporous silica nanoparticles (MSNs) from the unique (NH 4 ) 2 SiF 6 -NH 4 F solution produced from coal fly ash was developed using template assisted rapid chemical precipitation method. This work achieved the synthesis of MSNs with specific surface area (SSA) (~ 500 m 2 /g—1064 m 2 /g), small particle size (~ 90 nm- 133 nm) with narrow pore size distribution ranging between (7.56 nm- 20.11 nm) and reduced agglomeration condition by proposing a unique reactant’s feeding pattern and studying other parameters aiding the controlled synthesis process. The effect of high concentration fluoride ion on cationic cetyltrimethylammonium bromide (CTAB) template was also investigated. A novel CTAB removal method from the highly porous cavities of the silica nanoparticles under mild conditions was proposed. At 50 °C and atmospheric pressure, the foam fractionation technique showed 61% efficiency of CTAB removal while maintaining the porous structure and surface silanol of the particles compared with the traditional calcination method, providing green, economic and sustainable method for surfactant removal in MSNs.
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DOI
高影响因子
PHOSPHORUS SULFUR AND SILICON AND THE RELATED ELEMENTS
·
2026
·
IF 1.3
Wei Li,Bangfu Huang,Yihang Shi,Kui Zheng
To investigate the effects of NH4F and NH4Cl on the crystallization process of ammonium sulfate, experiments were designed using response surface methodology. Combined with the evaporation crystallization method, the study explored the combined effects of NH4F and NH4Cl, stirring rate, and pH on crystallization. The results indicate that the synergistic ratio of NH4F to NH4Cl and stirring rate significantly influence the crystallization yield of ammonium sulfate, with the order of effect intensity being synergistic ratio of NH4F to NH4Cl > stirring rate > pH value. The interaction between the synergistic ratio and stirring rate significantly affects the crystallization yield. All three factors significantly influence the average particle size, with their effects following the same pattern as crystallization quantity. Furthermore, the synergistic interaction between crystallization quantity and pH value significantly impacts particle size. The model predicted optimal process parameters as follows: NH4F:NH4Cl = 3:1, stirring speed = 200 rpm, pH = 4.74. Under these conditions, the theoretical crystallization yield was 57.39 g with an average particle size of 1.25 mm. Validation experiments showed that the actual crystallization yield under these conditions was 58.47 g with an average particle size of 1.23 mm, indicating a small error margin.
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高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Shaoxiang Xu,Meihua Zhu,Pengming Huang,Shengao Zheng,Yujie Qiao,Yuan Liang,Xiangshu Chen,Hidetoshi Kita
Nano-size titanium silicalites is difficult to be separate from the reaction solution, lamellar and homogeneous Ti-MWW zeolites are successfully formed a dense zeolite layers on α-Al 2 O 3 pellets by secondary hydrothermal synthesis in this study. Seeded crystals concentration and titanium source have significantly influences on the morphology, thickness and titanium active sites of Ti-MWW zeolites. Doping NH 4 F in the precursor synthesis solution could conducive to prepare macroscopically and anatase-free Ti-MWW zeolites layer on the outside of α-Al 2 O 3 pellets, and the thickness of the Ti-MWW zeolites layer is ca. 1 mm. Besides, catalytic performance of the supported Ti-MWW zeolites are significantly improved by NH 4 F. A fixed-bed reactor with the supported Ti-MWW zeolites are applied to catalyze phenol hydroxylation with hydrogen peroxide efficiently, and reaction time and temperature, amount of the supported Ti-MWW zeolites have obvious effects on the phenol conversion and dihydroxybenzene selectivity. When the actual mass of Ti-MWW zeolites to volume of reaction solution is only 10 g/L, the relative phenol conversion and dihydroxybenzene selectivity are 46.45% and 92.72% at 65 °C after 3 h, respectively.
研究领域:
催化
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材料科学
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化学工程
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DOI
高影响因子
ChemSusChem
·
2019
·Vol. 12
·期 16
·3871-3877
·
IF 7.804
Dan Wu,Xing Yu,Xinqing Chen,Gan Yu,Kun Zhang,Minghuang Qiu,Wenjie Xue,Chengguang Yang,Ziyu Liu,Yuhan Sun
Graphical Stacks on ! H-type MFI zeolite catalysts with a unique stacked structure are synthesized in a one-pot procedure in the presence of NH 4 F with the help of zeolite confinement through a solvent-free route without further ion-exchange procedures. The catalysts display excellent catalytic performance in methanol-to-gasoline reactions. H-type aluminosilicate zeolites are extensively used as solid-acid catalysts and support materials in industrial catalysis. However, the conventional synthesis methods involving hydrothermal syntheses and ion-exchange processes suffer from severe water pollution and toxic gas emissions. Herein, H-type MFI zeolite catalysts with a unique stacked structure were directly synthesized in the presence of NH 4 F and with the help of zeolite confinement through a solvent-free route without further ion-exchange procedures. A range of ex situ and in situ characterization procedures were used to provide evidence of the simultaneous use of pre-made ZSM-5 and NH 4 F as a confined Al source and mineralizer, respectively. The confined zeolite framework of ZSM-5 prevented the formation of AlF x species between NH 4 F and Al atoms, ensuring that the prepared samples had desirable acidic properties. Moreover, the resulting morphology could be controlled by using different silica substrates. The obtained H-type MFI zeolites showed excellent catalytic performance in methanol-to-gasoline reactions owing to their unique structure and directly exposed acidic sites. The developed one-pot strategy provides an alternative method for the facile synthesis of H-type zeolites with defined morphology.
研究领域:
材料科学
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催化
·
化学工程
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DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Ying Qi,Huaming Yang,Chunli Li,Hao Li
During the storage/transportation of fruits and vegetables, ethylene-induced over-maturation and spoilage is a serious problem. Currently developed ethylene adsorbents exhibit great potentials due to their low cost and high efficiency, but always lack of water resistance. Herein, we developed Ag/F-Z5(X) adsorbents via the modification of ZSM-5 with different amounts of NH 4 F followed by silver loading, which exhibits enhanced ethylene adsorption and water resistance. Among the samples, Ag/F-Z5(25) featured with the largest capacity (6.44 mg·g −1 ) and the best water resistance, achieving near-complete removal of trace ethylene (100 ppm) at room temperature. Based on the characterizations, NH 4 F modification induced a hierarchical structure within the ZSM-5 framework, concurrently enhancing surface acidity, increasing the proportion of Ag + , and improving the dispersion of metals in the adsorbents. These enhancements collectively contribute to enhanced adsorption and water resistance. Further, banana storage experiments confirmed the actual preservation ability of Ag/F-Z5(25) thanks to the better adsorption and water resistance than unmodified Ag/Z5. These findings offer meaningful insights for developing high-efficient and water-resistant adsorbents to remove trace ethylene, consequently mitigating food aste and enlarging the commercial value of agricultural products.
研究领域:
农业工程
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食品科学
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
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IF 4.1
Yi Liu,Kaishi Ding,Xiao Fan,Sixing Chen,Shengyan Meng,Jiahui Yan,Yunlei Gao,Jinming Lu,Yi Liu
Despite that oriented MFI zeolite films exhibit significant prospects for a wide range of applications due to microstructural superiority, their precise orientation control entails rigorous demands on reaction conditions (e.g., reaction temperature). In this work, we achieved facile synthesis of continuous b -oriented MFI zeolite films with few twins over a wide crystallization temperature range of 30–210 °C through adopting NH 4 F-mediated gel as nutrient during epitaxial growth. Both ammonium ions and fluorine ions were found crucial for enhancing the gel reactivity, endowing epitaxial growth with higher crystallization rates; moreover, the above morphology could be maintained even under fluctuating temperature conditions during film processing, thereby showing great potential for their bath production in a facile and reproducible manner.
研究领域:
材料科学
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化学工程
·
催化
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 1
·122-135
·
IF 3.094
Jingkun Xu,Zunlan Hu,Yao Han,Di An,Zhipeng Xie
In the present work, high-quality MgSiN 2 powders were prepared by a combustion synthesis method, based on Mg-Si 3 N 4 -N 2 system. The effects of additive content (NH 4 Cl or NH 4 F) and N 2 pressure on phase composition and crystal morphology of products were investigated. The results suggested that both NH 4 Cl and NH 4 F additives alleviated agglomeration and decreased the grain size of MgSiN 2 . In addition, NH 4 Cl did not result in the formation of an extra impurity, while MgF 2 residue was found when NH 4 F was introduced. Therefore, NH 4 Cl additive was considered as a better choice for the preparation of MgSiN 2 powders in comparison with NH 4 F additive. According to the observation of some MgSiN 2 whiskers and notably increased Si content under low N 2 pressure, the pressure of N 2 over 0.5 MPa was essential to have a complete reaction in the present work. Finally, MgSiN 2 -Si 3 N 4 composite powders with quasi-spherical morphology were prepared by adding excessive Si 3 N 4 and NH 4 Cl additive in reactant. The formation and growth mechanism of MgSiN 2 grains was reasonably speculated based on the experimental results. Because of the remarkable merits, the as-prepared Si 3 N 4 -MgSiN 2 composite powders showed great potential for alternative sintering aid in the sintering of Si 3 N 4 -based ceramics.
研究领域:
材料科学
·
陶瓷
·
合成方法
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）