International Journal of Minerals Metallurgy and Materials
·
2023
·Vol. 30
·期 4
·756-765
·
IF 4.8
Liu Yunsong,Wang Enhui,Xu Linchao,Yang Tao,He Zhijun,Liang Tongxiang,Hou Xinmei
Different amounts of AlON have been introduced in calcium hexaaluminate (CA 6 ) using two approaches, that is, one-step and two-step methods, to improve the slag resistance of CA 6 . A one-step method can directly sinter the mixtures combining Al 2 O 3 , CaCO 3 , and Al in flowing nitrogen, in which AlON clusters are always formed because of the poor wettability of Al by Al 2 O 3 , leading to the high porosity of CA 6 /AlON composite. In a two-step method, CA 6 and AlON are prepared separately and then mixed and sintered in flowing nitrogen. Compared with the sample prepared by the one-step method, CA 6 and AlON in composite by the two-step method are more uniformly distributed, and the optimized amount of AlON added is 10wt%. The slag corrosion and penetration test shows that the CA 6 /AlON composite using the two-step method exhibits superior slag corrosion protection. The promoted effect of AlON on slag penetration and corrosion resistance is also discussed.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
NUCLEAR ENGINEERING AND DESIGN
·
2024
·
IF 1.9
Changfu Wang,Lin Li,Xu Liu,Bobo Shao,Yan Liu,Yun Wang,Shengheng Tan,Zhirong Liu,Shengdong Zhang
The two-step vitrification process involves converting high-level waste from a liquid to a solid state through calcination , followed by melting the calcines with glass matrix material to form glassy wasteforms. The calcination process is a critical stage in the vitrification process. This study investigated the thermal decomposition performance and phase evolution of power reactor simulated high-level waste during the calcination process. As the calcination temperature increased from 100 to 900 °C, the resultant waste calcines showed increasingly darker color and smaller general particle sizes. Below 600 °C, the waste experienced thermal decomposition of nitrate and formate compounds, leading to an approximate 40 wt% weight reduction. At 600 °C, the waste's weight remained constant, and crystalline phases such as Zr x M 1-x O 2 (M = Ce, Pr, Nd), BaMoO 4 , CeO 2 , and Gd x Ce 1-x O 2 were observed.
研究领域:
核化学与化工
·
放射性废物处理
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 12
·126401
·
IF 1.929
Jianrui Zha,Shuya Wei,Huarui Han,Feng Wang,Qinlin Ma
Calcium oxalate film was prepared by a novel two-step method on the surface of the marble substrate. The seed film was coated by a chemical reaction process, providing a good connection to the marble surface. Meanwhile, calcium oxalate solution was interwoven into the seed film to form a continuous network at room temperature. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results indicated that the calcium oxalate film prepared by the two-step method showed a more intensive crystallinity degree and homogenous than that by the traditional oxalate treatment method (a scattered seed film). Subsequently, it was found such calcium oxalate film is feasible for preventing the marble substrate from chemical weathering. Furthermore, the change of the chromatic value, water absorption properties and adhesion strength of the marble substrates by the film is minimal. This method overcomes the limitations of traditional oxalate treatment process and has great potential for the protection of marble artifacts.
研究领域:
材料科学
·
文物保护
✓ 已验证
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2024
·Vol. 30
·期 45
·e202400800
·
IF 3.9
Yangyang Ma,Mengge Li,Tianliang Lu,Xiaomei Yang,Lipeng Zhou
Graphical A two-step depolymerizing strategy of high-pressure CO 2 −H 2 O pretreatment and oxidation-hydrolysis is applied for selective degradation of corn straw to glucose production. As high as 32.2 % yield of glucose is achieved without additional catalyst and the active acid sites generated during the partial oxidation on glucose units of cellulose is crucial. Depolymerization of the cellulose part in lignocellulose to glucose is a significant step for lignocellulose valorization. As one of the main by-products of agricultural biomass in crop-producing filed, valorization of corn straw has attracted considerable attention. In this study, a two-step depolymerizing strategy of high-pressure CO 2 −H 2 O pretreatment and oxidation-hydrolysis was applied for selective depolymerization of the cellulose component of corn straw to glucose production. Most part of the hemicellulose component could be removed through high-pressure CO 2 −H 2 O pretreatment in the presence of low concentration of acetic acid, and then as high as 32.2 % yield of glucose was achieved in water at 170 °C for 6 h without additional catalyst. The active acid sites generated during the partial oxidation of hydroxymethyl groups to carboxyl groups on glucose units of cellulose was shown to be crucial for the efficient valorization of corn straw for glucose production.
研究领域:
生物技術
·
可再生資源利用
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Shuaiqi Li,Zi'ang Fan,Yulong Li,Yue Zhang,Youxin Zhao,Jingxiang Zhao,Jingjia Zhang,Zhenbo Wang
The quest for platinum-based catalysts with enhanced catalytic efficacy and durability during the methanol oxidation reaction (MOR) has been a focal point in energy conversion science. Traditional platinum-based catalysts are often constrained by their high platinum content, which escalates economic costs and complicates experimental protocols. In this study, we introduce a low-platinum-loaded catalyst synthesized via a two-step method, which incorporates a four-component alloy. This innovative approach significantly reduces platinum content while maintaining superior catalytic performance through precise control over the alloy’s composition and structure. The two-step synthesis methodology streamlines the conventional multi-step processes, enhancing the catalyst preparation’s efficiency and reproducibility. The resulting PtCoSnCu/N-C alloy catalyst exhibits remarkable catalytic activity in methanol solution, with mass activity and specific activity that are 9.73 and 9.75 times higher, respectively, than those of commercial platinum on carbon (Pt/C) catalysts. Notably, the optimized PtCoSnCu/N-C alloy catalyst demonstrates exceptional long-term stability, outperforming Pt/C in aging and extended stability tests. Density functional theory (DFT) calculations elucidate the optimization of the electronic structure and the synergistic effect of surface atoms in the PtCoSnCu/N-C catalyst, which mitigates the adsorption energy of CO molecules and enhances the utilization rate of active sites during the oxidation process. This research presents a paradigm-shifting low-platinum catalyst strategy for methanol fuel cells, establishing a theoretical foundation for catalyst design and optimization.
研究领域:
能源化学
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Jingwei Liu,Xuhao Fan,Yufeng Tao,Chunsan Deng,Kewang Yu,Wenguang Zhang,Leimin Deng,Wei Xiong
The widespread use of stimuli-responsive hydrogels is closely related to their synthesis efficiency. However, the widely used thermal-responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogels usually require a time-consuming synthesis process to produce (more than 12 h) and exhibit a relatively slow response speed in the field of cryo-polymerization. In this study, a sequence of thawing polymerization after freezing polymerization by a two-step method of free radical polymerization for the efficient synthesis of PNIPAM hydrogels (merely 2 h) with an excellent comprehensive performance is demonstrated. Results show that the overall performance of the as-synthesized PNIPAM hydrogels is at the top level among reported works despite the significantly reduced preparation time. Moreover, after incorporating multi-walled carbon nanotubes (MWNTs), the PNIPAM hydrogels exhibit a rapid near-infrared (NIR) light-response and programmable shape-morphing capability. It is believed that such a viable and time-saving synthetic method for producing PNIPAM hydrogels of high performance will lay a solid foundation for drug delivery and smart actuators.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 4
·578-583
·
IF 1.248
Song Menglu,Yang Xiangui,Wang Gongying
Polycarbonate diols(PCDLs) with a number average molecular weight( M n ) of 2800 and a narrow polydispersity index(PDI=1.33) were synthesized from dimethyl carbonate(DMC) and 1,4-butanediol(BD) via a two-step process. The influences of the molar ratios of DMC to BD in the feedstock, polycondensation temperature and polycondensation time on the PCDLs preparation were studied. CH 3 COONa showed the best catalytic performance among the catalysts studied. The highest BD conversion of 73.8% and PCDLs yield of 64.7% were achieved under its optimum reaction conditions. Furthermore, based on the results of 1 H NMR, the relationships between the ratio of end groups (—OCH 3 /—OH) of oligomers, the M n and chainend constitute of resultant polycarbonates were also investigated. The results indicate that PCDLs can be synthesized when the oligomers mostly bear hydroxyl end groups. In contrast, it was impossible to prepare PCDLs when the oligomers were enriched with methyl carbonate end groups.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Jiahe Yan,Yucui Hou,Shuhang Ren,Muge Niu,Weize Wu
Because of its controllable and recoverable properties, the H2O–SO2 system was studied as a reaction medium to hydrolyze corn cob to produce chemicals by a two-step treatment. The results indicated that, after the first-step treatment of corn cob, 27.0% xylose, 3.3% glucose, and 3.2% arabinose could be obtained at 140 °C for 1.5 h with 0.024 g/cm3 SO2; after the second-step treatment, 8.6% glucose could be obtained at 190 °C for 0.5 h with 0.048 g/cm3 SO2. The total yield of products by the two-step treatment of corn cob was 48.4%, which was greater than that obtained by the one-step treatment, 32.4% at 190 °C for 0.5 h with 0.048 g/cm3 SO2. Furthermore, the degradation products obtained from the two-step treatment were less than those obtained from the one-step treatment. More importantly, after the reaction, SO2 could be swept by stream stripping and reused.
研究领域:
生物化学
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Jiaochun Zheng,Mao Deng,Yang Shi,Zhangyi Huang,Haomin Wang
The cold sintering process, a novel technique for low-temperature ceramic processing , effectively removes interparticle pores via dissolution and re-precipitation. However, it often triggers grain growth, especially in nanocrystalline ceramics. To address this issue, the present study proposed an innovative two-step cold sintering process with an initial step at 1.5 GPa/RT (room temperature) for 10 min, followed by a subsequent step at 300 MPa/250 °C for 45 min. This method yields ZnO nanocrystalline ceramics with 97.5 % relative density and a 39 nm average grain size (from 30 nm powder). The initial high-pressure step significantly enhances the pressure gradient and particle solubility, leading to very high supersaturation and the occurrence of homogenous nucleation during pressure release. Subsequently, the formation of the crystal nuclei in the interparticle voids can dramatically improve the density of the compact by the additional pore filling and avoid recrystallization-induced grain growth during the second-step cold sintering process.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2020
·
IF 7.489
Lin Cheng,Qingsong Zhang,Min Xu,Qingchao Zhai,Chenglong Zhang
“Two-for-one” strategy is an effective method to construct two kinds of materials from a single precursor owing to the simplicity of fabricating procedure and reduction of manufacturing cost. However, such a strategy has seldom been utilized to produce both battery-type and capacitive electrodes of a hybrid supercapacitor (HSC) device. Here, we adopt the “two-for-one” strategy to fabricate three-dimensional (3D) porous iron-doped (Fe-doped) Co 3 O 4 and nitrogen-doped ( N -doped) carbon via a single bimetallic metal–organic framework, FeCo-ZIF-67. Fe-doped amounts and carbonization temperature are used to adjust their individual electrochemical behaviors. The optimal 3D porous Fe-doped Co 3 O 4 and N -doped carbon possess a high capacitance of 767.9 and 277C g −1 at 1 A g −1 , respectively. Charge storage mechanism of Fe-doped Co 3 O 4 is further investigated via analysis of capacitive and diffusion-controlled contribution. A Fe-doped Co 3 O 4 // N -doped carbon HSC device achieves desirable specific energy (37 Wh kg −1 ) and power (750 Wkg −1 ), and satisfied cycling stability (90% retention after 4000 cycles). A light-emitting diode (LED) is successfully light by the HSC device, suggesting its potential application in the field of green energy conversion and storage devices.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Ying-Bo Zhu,Jia Guo,Yu-Long Ma,Yuan-Yuan Li
The production of high-value-added chemicals from the degradation of real lignin still has been an unresolved issue. In this study, a two-step strategy was proposed to obtain n-hexanol from alkali lignin, and high conversion of alkali lignin and selectivity of n-hexanol were achieved. The deoxygenation performance of the synthesized Ni-HZSM-5 catalyst, modified by Ca, was efficiently improved. At first, through the deoxygenation of alkali lignin via Ni/CaO-HZSM-5, the C–O bonds of the material were broken effectively and 44% degree of deoxygenation (DOD) was obtained. Second, n-hexanol was selectively produced over the Ni/HZSM-5 catalyst from the liquid product obtained by the first step. The efficiency of deoxygenation (DOD) was attained at 71%, and the heat value increased to 51.6 MJ/kg from 19.9 MJ/kg after the two-step strategy. This strategy showed a high catalytic effect to produce n-hexanol from alkali lignin using Ni/CaO-HZSM-5 and Ni/HZSM-5 catalysts and revealed a superior advantage in the hydrodeoxygenation of real lignin to form high additional value chemicals.
研究领域:
化学工程
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
ChemNanoMat
·
2019
·Vol. 6
·期 5
·806-815
·
IF 3.431
Tingting Xu,Xuelin Sun,Weiwei Cao,Xiulan Qin,Ashim Gurung,Shaoshen Lv,Yonghua Chen,Lixin Chen,Wei Huang,Qiquan Qiao
Graphical Quality of perovskite film has a great influence on the performance of perovskite solar cells. Herein, perovskite films with large-sized grains were obtained by introducing Lewis base urea into the MAI solution for two-step processing. Compared to the perovskite films without urea treatment, the perovskite films prepared with the optimal urea concentration of 0.4 mg/mL show fewer grain boundaries and defects, the carrier transport is also improved. The photovoltaic performance of the as-fabricated carbon-based perovskite solar cells achieves significant improvement up to 13%. Perovskite solar cell has made a steady research progress with superior photovoltaic power conversion efficiency (PCE) over 25%. The quality of perovskite film is a key factor affecting device efficiency. Lewis bases such as urea, DMSO and thiourea etc. have been applied in perovskite precursor solutions for one step processing to effectively control the film morphology. Herein, we report urea treatment in a two-step processing for obtaining high quality methylammonium lead triiodide perovskite (CH 3 NH 3 PbI 3 ) film, which is accomplished by immersing the PbI 2 film into the mixture solution of urea/methylammonium iodide (MAI). The optimized urea concentration in the MAI solution is 0.4 mg/mL, leading to larger-sized and better crystalline perovskite grains than that without urea additive. The main function of the urea additive is the formation of the adduct MAI⋅PbI 2 ⋅O=C(NH 2 ) 2 , retarding the crystallization process of the perovskite film. The steady-state and time-resolved photoluminescence measurements revealed that perovskite CH 3 NH 3 PbI 3 grown using optimized concentration of urea has prolonged carrier lifetime and reduced carrier recombination. Finally, the carbon-based perovskite solar cells fabricated from the optimal urea concentration of 0.4 mg/mL achieved the enhanced photovoltaic performance with the highest PCE of 13.10% and an average value of 11.34%, in comparison to devices without urea treatment exhibiting an average PCE of only 8.67%.
研究领域:
材料科学
·
能源技术
·
光伏器件
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）