JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Min Wei,Lei Huang,Shangli Huang,Zhenyu Chen,Dandan Lyu,Xiaoran Zhang,Shuangbao Wang,Zhi Qun Tian,Pei Kang Shen
Improving utilization of precious metals is one of the crucial challenges for electrochemical energy catalysis. Tuning precious metal structure to expose active sites is an effective strategy to reduce mass loading in the practical application. Herein, Pt-Co hollow nanospheres were synthesized via a sequential reduction strategy using amorphous Co-B-O complex as the key spheres-forming intermediates. The modulation mechanism of Pt-Co hollow nanospheres formation was established by investigating critical factors of addition sequence of reducing agent, the type of reducing agents and the ratio of Pt and Co precursors. The optimized Pt-Co hollow nanospheres with the Pt/Co molar ratio of 1:1 by this method is characterized by the average diameter of around 30 nm and the shell thickness of 2.3 nm. They displays superior performance for enhanced hydrogen evolution reaction (HER) in the aspect of activity and stability in 0.5 M H 2 SO 4 , in which the mass activity of the Pt-Co hollow spheres exhibits 2.82 times higher than that of commercial Pt/C and its stability also has a significant enhancement. The outstanding activity of the Pt-Co hollow nanospheres for HER is mainly attributed to its highly accessible electron/mass transport path, expose active sites on the ultra-thin shells and strain effect induced by the hollow sphere structure. This hollow nanospheres with ultra-thin shell provides a promising way to develop highly efficient precious metal based electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Si-Ke Chen,Da-Wei Pan,Zhuang Liu,Wei Wang,Rui Xie,Xiao-Ting Mu,Xiao-Jie Ju,Liang-Yin Chu
A simple microfluidic strategy is proposed for the controllable preparation of calcium alginate/chitosan (CaA/CS) microcapsules with ultrathin shells for peroxidase immobilization. In this study, the composite microcapsules are composed of CaA and CS, which are beneficial to improve the stability of CaA microcapsules, and are generated using a two-stage capillary microfluidic device. The inner layer of the composite capsule shells is ionically cross-linked CaA, and the outer layer is covalently cross-linked CS. Moreover, the Fe3O4 magnetic nanoparticles are added to facilitate the recovery and reuse of the composite microcapsules. The morphology, permeability, encapsulation efficiency, enzyme activity, and reusability of CaA/CS microcapsules are investigated. The overall thickness of the double-layered shell is about 346 nm. Meanwhile, the microcapsules have good molecular selective permeability, excellent encapsulation performance, stable enzyme activity, and good stability for reusability. The composite microcapsules retained above 80% of residual activity after six recycle uses. The developed novel strategy for fabricating peroxidase-immobilized CaA/CS microcapsules with ultrathin shells is of great potential value for enzyme immobilization applications.
研究领域:
生物技术
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材料科学
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酶工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 41
·11104-11110
·
IF 5.976
Song Wei,Yue Liu,Mingyue Ma,Yao Wu,Lijian Huang,Daocheng Pan
To reduce the charge injection barrier, we attempt to synthesize thin-shell CdSe/ZnxCd1−xS core/shell quantum dots (QDs) in this work. A low-temperature (90–115 °C) synthetic scheme was developed for highly luminescent CdSe/ZnxCd1−xS core/shell QDs by employing short-chain tert-dodecanethiol as the ligand and low-boiling xylene or octane as the solvent. Thiol-capped CdSe/2ZnxCd1−xS core/shell QDs with two monolayers of the shells were directly synthesized in open air, including CdSe/2ZnS, CdSe/2Zn2/3Cd1/3S, CdSe/2Zn1/2Cd1/2S, CdSe/2Zn1/3Cd2/3S, CdSe/2CdS, and CdSe/1CdS/1ZnS core/shell QDs. These short-chain ligand capped and thin-shell QDs were used as the emitting layers to fabricate quantum dot light emitting diodes (QD-LEDs). The results showed that QDs coated with an alloyed Zn0.5Cd0.5S shell possess the optimal photoluminescence (PL) and electroluminescence (EL) properties as well as a maximum current efficiency of 12.5 cd A−1.
研究领域:
材料科学
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纳米技术
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光电技术
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Xueqing Wu,Chuntao Cao,Ruwei Yao,Tingjun Fu,Zhong Li
A core-shell structured S-1@ZSM-5 was prepared by a seed-induced method, and its physicochemical properties and catalytic performance in methanol aromatization were studied based on the growth control of ZSM-5 shell. Results revealed that the ZSM-5 shell can be well coated on the surface of the silicalite-1 (S-1) seed under a low temperature crystallization, which induced the formation of worm-like morphology with a controllable shell thickness of 30 nm. Importantly, the weak acid sites dominated by Lewis acid sites can be constructed based on the control of growth degree. For methanol aromatization, the weak acid sites not only ensured the aromatization reaction, but also inhibited the isomerization and alkylation of para-xylene. The selectivity of aromatics and para-xylene in xylene reached 25.96% and 47.53%, respectively. The thin shell promoted the rapid removal of the coke precursor, which gave the catalyst a relatively long lifetime. Interestingly, on such a shell with weak acid sites, the limited sites can be easily covered by coke deposition along with the reaction progress, and thus the para-xylene selectivity can be gradually increased to 73.81%. Additionally, protective desilication was implemented for core-shell catalysts, and the aromatic selectivity was decreased while the catalytic lifetime and para-xylene selectivity remained unchanged. This reflected the inherent catalytic stability for methanol aromatization due to the thin shell and weak acidity. This work provides a new preparation strategy for ZSM-5 with high para-xylene selectivity and catalytic lifetime based on the direct synthesis of suitable acid sites and the diffusion channels.
研究领域:
催化
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化学工程
·
材料科学
·
化学
✓ 已验证
DOI
高影响因子
Nanoscale
·
2020
·Vol. 12
·期 47
·24070-24078
·
IF 6.895
Jinhui Zhu,Min Wei,Qinghao Meng,Zhenyu Chen,Yepeng Fan,Syed Waqar Hasan,Xiaoran Zhang,Dandan Lyu,Zhi Qun Tian,Pei Kang Shen
Improving the utilization of Ir electrocatalysts for the oxygen evolution reaction (OER) to significantly reduce their loading is essential for low-cost hydrogen production in proton exchange membrane water electrolysis. Herein, IrCo hollow nanospheres featuring a novel structure with ultrathin continuous shells which have only eleven atomic layers (2.26 nm) were synthesized by a facile sequential reduction route using NaBH4 as a reducing agent at room temperature. It is revealed that the key intermediate in the formation of hollow nanospheres is amorphous cobalt boride formed between Co2+ and NaHB4 in the first reducing step. The average diameter of the IrCo nanospheres was found to be 73.71 nm with the atomic ratio of 47.1% and 52.9% for Co and Ir, respectively. The IrCo hollow nanospheres exhibit highly efficient OER activity and long-term durability with a low overpotential of 284 mV at 10 mA cm−2 (32.5 μgIr cm−2) and a high mass activity of 8.49 A mg−1 (5.7 times higher than that of commercial IrO2 (1.49 A mg−1) at 1.7 V. The performance is also proved using an overall water splitting device with the overpotential of 318 mV to achieve 10 mA cm−2 as well as a 17 mV shift at 5 mA cm−2 after 14 h. This improvement is critically attributed to the advantages of the hollow structure, ultrathin continuous shells which are oxidized into IrOxin situ and strong lattice strain effects induced by the specific hollow structure and alloying Co into Ir crystal lattices (1.6% against metallic iridium). These characteristics endow the hollow nanospheres with great potential to minimize the Ir loading dramatically for practical applications, compared to other previously reported structures like nanoparticles, nanoneedles and nanowires.
研究领域:
材料科学
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电化学
·
纳米技术
·
催化
·
能源材料
✓ 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）