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143 results on '"Deng, Jiujun"'

14. Flash Joule Heating Synthesis of Layer-Stacked Vanadium Oxide/Graphene Hybrids within Seconds for High-Performance Aqueous Zinc-Ion Batteries

Author

Lv, Xiaoxin, Yang, Aomen, Wang, Menglian, Nie, Kaiqi, Deng, Jiujun, and Sun, Xuhui

Abstract

Vanadium oxides have been regarded as highly promising cathodes for aqueous zinc-ion batteries (ZIBs). However, obtaining high-performance vanadium oxide-based cathodes suitable for industrial application remains a significant challenge due to the need for cost-effective, straightforward, and efficient preparation methods. Herein, we present a facile and rapid synthesis of a composite cathode, consisting of layer-stacked VO2/V2O5and graphene-like carbon nanosheets, in just 2.5 s by treating the commercial V2O5powder via a flash Joule heating strategy. When employed as the cathode for ZIBs, the resulting composite delivers a comparable rate capacity of 459 mA h g–1at 0.2 A g–1and remarkable cycle stabilities of 355.5 mA h g–1after 2500 cycles at 1.0 A g–1and 169.5 mA h g–1after 10,000 cycles at 10 A g–1, respectively. Further electrochemical analysis reveals that the impressive performance is attributed to the accelerated charge transfer and the alleviated structure degradation, facilitated by the abundant sites and a built-in electric field of the layer-stacked VO2/V2O5heterostructure, as well as the excellent conductivity of graphene-like carbon nanosheets. This work introduces a unique approach for ultrafast and low-cost fabrication of high-performance vanadium oxide-based composite cathodes toward efficient ZIBs.

Published
2024
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36. Fe-doped SnO2 nanosheet for ambient electrocatalytic nitrogen reduction reaction.

Author

Li, Yaxi, Liu, Yixian, Liu, Xiang, Liu, Yunliang, Cheng, Yuanyuan, Zhang, Peng, Deng, Peiji, Deng, Jiujun, Kang, Zhenhui, and Li, Haitao

Abstract

Ammonia plays a vital role in the development of modern agriculture and industry. Compared to the conventional Haber—Bosch ammonia synthesis in industry, electrocatalytic nitrogen reduction reaction (NRR) is considered as a promising and environmental friendly strategy to synthesize ammonia. Here, inspired by biological nitrogenase, we designed iron doped tin oxide (Fe-doped SnO2) for nitrogen reduction. In this work, iron can optimize the interface electron transfer and improve the poor conductivity of the pure SnO2, meanwhile, the synergistic effect between iron and Sn ions improves the catalyst activity. In the electrocatalytic NRR test, Fe-doped SnO2 exhibits a NH3 yield of 28.45 μg·h−1mgcat−1, which is 2.1 times that of pure SnO2, and Faradaic efficiency of 6.54% at −0.8 V vs. RHE in 0.1 M Na2SO4. It also shows good stability during a 12-h long-term stability test. Density functional theory calculations show that doped Fe atoms in SnO2 enhance catalysis performance of some Sn sites by strengthening N—Sn interaction and lowering the energy barrier of the rate-limiting step of NRR. The transient photovoltage test reveals that electrons in the low-frequency region are the key to determining the electron transfer ability of Fe-doped SnO2. [ABSTRACT FROM AUTHOR]

Published
2022
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41. Metallic cobalt nanoparticles embedded in sulfur and nitrogen co-doped rambutan-like nanocarbons for the oxygen reduction reaction under both acidic and alkaline conditions

Author

Liu, Jinyuan, primary, Xu, Li, additional, Deng, Yilin, additional, Zhu, Xingwang, additional, Deng, Jiujun, additional, Lian, Jiabiao, additional, Wu, Jingjie, additional, Qian, Junchao, additional, Xu, Hui, additional, Yuan, Shouqi, additional, Li, Huaming, additional, and Ajayan, Pulickel M., additional

Published
2019
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45. Construction of 2D/2D Z-scheme MnO2-x/g-C3N4photocatalyst for efficient nitrogen fixation to ammonia

Author

Yu, Limin, Mo, Zhao, Zhu, Xianglin, Deng, Jiujun, Xu, Fan, Song, Yanhua, She, Yuanbin, Li, Huaming, and Xu, Hui

Abstract

Reducing nitrogen to ammonia with solar energy has become a wide concern when it comes to photocatalysis research. It is considered to be one of the more promising alternate options for the conventional Haber–Bosch cycle. Herein, 2D g-C3N4composites with modifying ultrathin sheet MnO2-xwere prepared and used as nitrogen fixation photocatalyst. With the assistance of the nature of MnO2-x, the generation rate of NH3reached 225 μmol g−1h−1, which is more than twice over the rate of pristine 2D g-C3N4(107 μmol g−1h−1). The presence of ultrathin sheet MnO2-xshortens the gap of the carriers to the surface of photocatalyst. Thus the speed of electron transfer gets increased. Besides, the construction of Z-scheme heterojunction boosts the separation and migration of photogenerated carriers. As a result, the nitrogen reduction reaction (NRR) performance gets enhanced. The work may provide an example of promoting the NRR performance of non-metallic compound.

Published
2021
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46. Accelerating the Hole Mobility of Graphitic Carbon Nitride for Photocatalytic Hydrogen Evolution via 2D/2D Heterojunction Structural Advantages and Ni(OH)2 Characteristic.

Author

Hao, Quanguo, Song, Yanhua, Mo, Zhao, Deng, Jiujun, Yi, Jianjian, El-Alami, Wiam, Xu, Hui, and Li, Huaming

Abstract

Although photocatalytic hydrogen evolution is significant for solar conversion and energy supply, the photocatalytic efficiency is hampered by the low photoinduced holes mobility. Herein, the 2D Ni(OH)2 as an operational cocatalyst is integrated with 2D graphitic carbon nitride (2D‐CN) ultrafine to form a 2D/2D heterojunction to improve the photocatalytic hydrogen evolution. Due to the high mobility attribute of the Ni(OH)2 holes and the unique 2D/2D heterojunction of Ni(OH)2/CN, the specific photocatalyst Ni(OH)2/2D‐CN accelerates the photocarrier separation/transport, thereby achieving the breakthrough of continuous photocatalytic hydrogen evolution without using Pt cocatalyst and sacrificial agent. Above all, the as‐obtained Ni(OH)2/2D‐CN exhibits a hydrogen evolution rate of 921.4 μmol h−1 g−1 with an external quantum efficiency of 5.21% at 400 nm using 10% triethanolamine as a sacrificial agent. The work provides a new research approach for the catalytic conversion of energy. [ABSTRACT FROM AUTHOR]

Published
2020
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50. Ti-doped hematite nanostructures for solar water splitting with high efficiency.

Author

Deng, Jiujun, Zhong, Jun, Pu, Aiwu, Zhang, Duo, Li, Ming, Sun, Xuhui, and Lee, Shuit-Tong

Subjects
*NANOSTRUCTURED materials synthesis, *HEMATITE, *TITANIUM, *PHOTOCURRENTS, *ELECTROLYTES, *SPECTRUM analysis, *ELECTRONIC structure
Abstract

Ti-doped hematite nanostructures have been synthesized for efficient solar water splitting by adding TiCN as the Ti precursor in a hydrothermal method. Ti-doped hematite nanostructures show an urchin-like morphology with nano feature size, which increases the effective surface area compared to undoped nanostructures. A remarkable plateau photocurrent density value of 3.76 mA/cm2 has been observed for Ti-doped nanostructures under standard illumination conditions in 1 M NaOH electrolyte, which is 2.5 times higher than that for undoped nanostructures (1.48 mA/cm2). The photocurrent at 1.23 V vs. RHE (1.91 mA/cm2) is also enhanced to be over 2 times higher than that for undoped nanostructures (0.87 mA/cm2). X-ray photoelectron spectroscopy and x-ray absorption spectroscopy have been used to investigate the electronic structure of Ti-doped hematite, which suggest the increased donor density of hematite by Ti doping. The remarkable plateau current density in Ti-doped hematite nanostructures can be attributed to both the favorable urchin-like morphology and the Ti doping. [ABSTRACT FROM AUTHOR]

Published
2012
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