Solar RRL
·
2022
·Vol. 6
·期 7
·2101103
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IF 9.173
Yao Li,Siqi Li,Yan Li,Xiangnan Sun,Xinding Lv,Yan-Zhen Zheng,Meilan Huang,Xia Tao
The substitution of a portion of methylammonium (MA) for guanidinium (GA) has been verified to be able to enhance the stability of MA-based devices. However, high-dose guanidinium cation will introduce localized distortions to the perovskite lattice structure and destroy the microstructure of the perovskite films, impairing the stability and reproducibility of perovskite solar cells (PSCs) eventually. Herein, for the first time, the NH 4 Br-assisted all-atmospheric two-step process is adopted to fabricate GA-rich (20%) perovskite films. The NH 4 Br induces the formation of the intermediate phase NH 4 PbI 3 and alleviates the disorder of the octahedron caused by the big GA. Consequently, the modified perovskite film shows increased tolerance for the roughness fluctuation and reduced risk of forming voids and pinholes. The fabricated compact GA-rich perovskite films behave extremely well in photovoltaic performance when assembled as carbon-based perovskite solar cells, delivering a high power conversion efficiency (PCE) of 16.19% and stability against moisture and sunlight. Especially, the unencapsulated devices in ambient air sustain 95.1%, 91.8%, and 95.7% of their initial PCEs after 2400 h of storage, after 1000 h of 65 °C heat environment, and after 800 h of sunlight illumination, respectively.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2022
·Vol. 33
·期 19
·15894-15903
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IF 2.779
Hu Zeqing,Xu Huihong,Lin Yangjian,Liu Yu,Xu Junsheng,Li Zhou,Song Jiming
Currently, Cu 2 GeS 3 has been obtained through solid-state reaction. However, the pure phase Cu 2 GeS 3 synthesized still faces challenges due to the low boiling point of the sulfur element. Herein, we have prepared pristine Cu 2 GeS 3 by a two-step method. Firstly, the pure phase GeS 2 was synthesized by solvothermal method and then used the freshly as-synthesized GeS 2 as raw material to react with copper powder to fabricate pure phase Cu 2 GeS 3 . Further, the thermoelectric properties of Cu 2 GeS 3 crystal have been explored. At room temperature, the electric resistance value measured by multimeter was ~ 2634 Ω for intrinsic Cu 2 GeS 3 crystal, which exceeded the instrument (electrical conductivity/Seebeck coefficient) test range of 0–2000 Ω, so there is no relevant report in the thermoelectric field about Cu 2 GeS 3 crystal. In order to improve its conductivity, Cu 2 GeS 3 crystal is alloyed with a small amount of Te powder to obtainable Cu 2 GeS 3− x Te x samples, which have obvious thermoelectric properties. By adjusting the content of Te, finally, the electrical conductivity of the Cu 3 GeS 2.6 Te 0.4 sample reached 364.20 S m −1 and the figure-of-merit ZT max value of ~ 0.12 were obtained at 816 K.
研究领域:
材料科学
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能源科学
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产品关联
DOI
高影响因子
Results in Chemistry
·
2023
·
IF 2.3
Hengwei Yan,Ye Kuang,Yonghui Yang,Jiyan Gao,Zhanwei Liu
Because direct roasting of aluminum fluoride hydrate will hydrolysis, resulting in higher alumina content in aluminum fluoride products. To solve this problem, a two-step process for the preparation of anhydrous AlF 3 from AlF 3 ·3H 2 O and NH 4 HF is described in this paper. First, AlF 3 ·3H 2 O was dried at 220 ℃ for 9–12 h, and then NH 4 HF (the mass ratio of AlF 3 ·3H 2 O to NH 4 HF was 1:20) was added, and the mixture was roasted from room temperature to 650 ℃. The results showed that the hydrolysis of aluminum fluoride can be avoided effectively by the two-step roasting method with NH 4 HF, the purity of the anhydrous AlF 3 was 99.8 wt%, and the concentration of alumina, the main impurity, was less than 0.1 wt%.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Environmental Science and Technology
·
2024
·
IF 3
Dou W.,Song Y.,Zhang Y.,Liu T.,Kong L.,Hu X.,Li D.
Removal of chloride (Cl(− I)) and fluoride (F(− I)) ions is a major issue in metallurgical waste acid recycling. This study explored the synchronous and two-step precipitation approaches using bismuth oxide (Bi 2 O 3 ) to remove Cl(− I) and F(− I). Under the mole ratio of Bi 2 O 3 and halide ions at respectively 0.3 and 0.7 for the first and second steps, residual concentrations of Cl(− I) and F(− I) below 100 and 50 mg/L, respectively, were obtained, where the removal proportions of Cl(− I) and F(− I) in the first and second steps were respectively 1:1.1 and 1:3.3. During the treatment, Bi 2 O 3 was dissolved to produce Bi 3+ , which reacted with Cl(− I) first and then F(− I), leading to the precipitation of bismuth oxychloride and bismuth oxyfluoride. After the removal of Cl(− I) and F(− I), residual Bi 3+ was removed to a final concentration of 1.3 mg/L through introduction of hydrogen sulfide (H 2 S) and recovered as bismuth sulfide (Bi 2 S 3 ). In this method, approximately 97.6% of Bi 2 O 3 was regenerated, additionally, Cl(− I) and F(− I) were transferred to a NaOH/NaCl/NaF concentrate with minimal volume. This two-step approach for the removal of Cl(− I) and F(− I) using Bi 2 O 3 exhibited excellent performance in terms of high efficiency, high reagent recovery rate and low secondary pollution risk.
研究领域:
环境科学
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冶金工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2017
·Vol. 7
·期 8
·237
·
IF 3.082
Guo Qiu,Xincheng Wang,Chongpin Huang,Yingxia Li,Biaohua Chen
The production of bio-diesel fuels from carbohydrates is a promising alternative to fossil fuels with regard to the growing severity of the environmental problem and energy crisis. Potential bio-diesel candidates or additives, such as 5-(hydroxymethyl)-2-(dimethoxymethyl) furan (HDMF), 2-(dimethoxymethyl)-5-(methoxymethyl) furan (DMMF), and 5-(methoxymethyl)-2-furaldehyde (MMF) could be produced from the alcoholic solutions of both 5-HMF and fructose in the presence of solid acid catalysts. In the present study, a readily prepared, silica, gel-supported nitric acid (SiO2-HNO3) catalyst was found to be exceptionally reactive for the production of HDMF from fructose. A DMSO-methanol biphasic solvent system was developed and HDMF, DMMF, and MMF were observed at 150 °C, with maximum yields of 34%, 34%, and 25%, respectively. Meanwhile, a maximum HDMF yield of 77% was obtained from 5-HMF in methanol. Moreover, a sequential, one-pot, two-step dehydration/acetalization process, involving the dehydration of fructose to 5-HMF in dimethylsulfoxide (DMSO) at 150 °C, and followed by adding a certain amount of methanol to react with the formed 5-HMF to HDMF at 100 °C, was developed to promote the yield of HDMF. The optimum yield of HDMF reached 70% with the complete conversion of fructose. The reaction mechanisms of dehydration and acetalization have been proposed for the conversion of 5-HMF to HDMF. The two-step design allows for facile catalyst recycling while supplying as a promising method for the production of biodiesel from complex carbohydrates.Keywords:bio-diesel;silica gel-supported nitric acid;one-pot two-step system
研究领域:
化学工程
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可再生能源
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产品关联
DOI
高影响因子
ADVANCED MATERIALS
·
2020
·Vol. 32
·期 42
·2004630
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IF 27.398
Minchao Qin,Haibo Xue,Hengkai Zhang,Hanlin Hu,Kuan Liu,Yuhao Li,Zhaotong Qin,Junjie Ma,Hepeng Zhu,Keyou Yan,Guojia Fang,Gang Li,U-Ser Jeng,Geert Brocks,Shuxia Tao,Xinhui Lu
Two-step-fabricated FAPbI 3 -based perovskites have attracted increasing attention because of their excellent film quality and reproducibility. However, the underlying film formation mechanism remains mysterious. Here, the crystallization kinetics of a benchmark FAPbI 3 -based perovskite film with sequential A-site doping of Cs + and GA + is revealed by in situ X-ray scattering and first-principles calculations. Incorporating Cs + in the first step induces an alternative pathway from δ-CsPbI 3 to perovskite α-phase, which is energetically more favorable than the conventional pathways from PbI 2 . However, pinholes are formed due to the nonuniform nucleation with sparse δ-CsPbI 3 crystals. Fortunately, incorporating GA + in the second step can not only promote the phase transition from δ-CsPbI 3 to the perovskite α-phase, but also eliminate pinholes via Ostwald ripening and enhanced grain boundary migration, thus boosting efficiencies of perovskite solar cells over 23%. This work demonstrates the unprecedented advantage of the two-step process over the one-step process, allowing a precise control of the perovskite crystallization kinetics by decoupling the crystal nucleation and growth process.
研究领域:
材料科学
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物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2013
·
IF 4.75
Jinping Ni,Hailiang Wang,Yinying Chen,Zhen She,Haining Na,Jin Zhu
A two-step acid-catalyzed hydrolysis methodology is established to effectively hydrolyze cellulose to glucose with high yield and selectivity under mild conditions. In multi-steps hydrolysis, the difficulty of cellulose can be effectively reduced under mild conditions. In the first step, microcrystalline cellulose was depolymerized in phosphoric acid to cellulose oligomer at 50 °C. Then the oligomer was precipitated by ethanol and hydrolyzed with dilute sulfuric acid in the second step. 87.7% total reducing sugars and 57.8% glucose was released from the two-step hydrolysis process. In addition, with the assistance of microwave in the second step, the yield and selectivity of glucose can be improved to 73.3% and 80.1% by only 5 min hydrolysis. The two-step hydrolysis exhibits an effective process to produce glucose in cellulose hydrolysis. The enhancement of hydrolysis reactivity is considered to be controlled with the decrease of crystallinity and degree of depolymerization of cellulose.
研究领域:
生物化学
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可再生资源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2023
·Vol. 54
·期 2
·712-733
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IF 3
Zhang Xi,Na Hao,Liu Pengyao,Wang Yajun,Li Junguo,Meng Qian,Li Guopeng
Regulating the phase transformation of γ → β in dicalcium silicate (C 2 S) can effectively improve the hydration activity and recycling rate of AOD slag; however, the evolution law for γ → β in C 2 S has not been extensively investigated. In this study, a novel “two-step” γ → α ′ L → β phase transformation method in C 2 S was designed based on the study of the pure C 2 S phase at a nonequilibrium state in the low- and middle-temperature ranges. The “two-step” method can be used to realize the transformation from needle-like nanostructured γ -C 2 S grains to lamellar-structured β -C 2 S grains, exhibiting the trend of interlaminar peeling accompanied by expansion of the particle volume and leading to the appearance of macroscopic lamellar cracking in β -C 2 S particles. In addition, the β -C 2 S mass fraction in AOD slag treated by water cooling at 680 °C reaches a maximum value of 47.5 wt pct, while the treated AOD slag presents abundant holes and defects, which can effectively enlarge the hydration contact area.
研究领域:
材料科学
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无机化学
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产品关联
DOI
高影响因子
POLYMER INTERNATIONAL
·
2011
·Vol. 61
·期 1
·111-117
·
IF 2.056
Bing Fang,Kai Pan,Qinghan Meng,Bing Cao
This study investigated the preparation of polyimide solvent-resistant nanofiltration membranes by a two-step method (casting the membrane first and then crosslinking by the thermal imidization method). The influences of polymer concentration, thickness of membranes, temperature of the imidization, phase inversion time and thermal imidization procedure were studied. The membranes with the highest rejection rate of Fast Green FCF (molecular weight 808.86 g mol −1 ) were prepared in the following conditions: polymer concentration 13 wt%, phase inversion time 1 h, membrane thickness 150 µm and thermal imidization procedure 200 °C for 2.5 h, 250 °C for 2 h and 300 °C for 2 h in a vacuum environment; the heating rate was 5 °C min −1 . The membrane was stable in most of the solvents tested and the fluxes of some common solvents were equal to or higher than a number of commercial solvent-resistant nanofiltration membranes. A much higher rejection of dyes in water than in methanol was observed in the filtration experiments and a new way to explain it was developed. Copyright © 2011 Society of Chemical Industry
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 5
·055013
·
IF 1.449
Lin Chu,Wenbin Niu,Suli Wu,Wei Ma,Bingtao Tang,Shufen Zhang,Heping Li,Zheng Liu
Owing to the simultaneous occurrence of nucleation and nuclei aggregation in nanoprecipitation approach, the preparation of monodisperse nanospheres from polysaccharide remains a great challenge. Herein a two-step approach is presented for size controlled preparation of monodisperse polysaccharide-based nanospheres with PDI of 0.05 from starch acetate (SA). First, the starch acetate nanospheres (SANs) with average size in the range from 100 to 160 nm were produced by a moderate and constant hydrophobic interaction (MCHI) process. Second, based on principle of Ostwald ripening, a facile hydrothermal method was employed to modulate the size of the SANs obtained from the first step, yielding monodisperse nanospheres ranging from 200 to 1400 nm. This two-step method was also successfully applied to the preparation of ethyl cellulose nanospheres, which provided a facile strategy to prepare nanospheres from polysaccharides. Finally, SANs (744 nm) and ECNs (802 nm) were used to fabricate 2D photonic crystals by self-assembly, further verifying high monodispersity of obtained polysaccharide-based nanospheres.
研究领域:
材料科学
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生物医学工程
✓ 已验证
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Ming Gu,Yue Tian,Cai’e Cui,Ping Huang,Lei Wang,Qiufeng Shi
A novel red-emitting Ba 2 ZrF 8 : Mn 4+ phosphor was prepared by two-step method at low temperature, where critical precursor K 2 MnF 6 was prepared first by the reduction of KMnO 4 using H 2 O2 as reducer. The crystal structure and morphology of the phosphor was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), showing single phase product. Luminescent properties of the phosphor were investigated by photoluminescence spectroscopy (PL) and decay curves. The molar ratio of KMnO 4 : KHF 2 was confirmed to play the key role in improving the luminous efficiency. More importantly, the phosphor exhibits a broadband excitation from 300 to 520 nm due to 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transition of Mn 4+ , matching well with blue LED chips. Under 465 nm excitation, intense red emission at around 630 nm with high color purity is achieved, suggesting the red-emitting phosphor has great potential for white light-emitting diodes (wLEDs).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Yongquan Qing,Chuanning Yang,Qingqing Zhao,Chuanbo Hu,Changsheng Liu
Multifunctional surfaces are in urgent demand in particular fields. In this work, we report a low-cost preparation of superhydrophobic/superoleophobic surfaces on copper substrate by rapid two-step process. The deposited Zn surface modified by stearic acid showed good superhydrophobicity with a water contact angle of 158.3° and a sliding angle of 4.6°. Interestingly, a remarkable Zn surface with reversible wetting transition between hydrophilicity and superhydrophobicity could be easily realized by the alternation of annealing and modifying. The wetting transition process was rapid and only took 13 min for each cycle, depending mainly on the change of the surface elements. Moreover, the modified-TiO 2 suspension was coated onto the deposited Zn surface to construct a composite surface with micro/nano rough structures, which possessed excellent superamphiphobicity with contact angles of 161.8° and 152° toward water and oil respectively, and showing great mechanical strength and stability. The novel materials exhibit a promising perspective in many applications, such as wettability transition of surfaces, water proof and oil proof.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）