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23. Controllable Metal–Organic Framework‐Derived NiCo‐Layered Double Hydroxide Nanosheets on Vertical Graphene as Mott–Schottky Heterostructure for High‐Performance Hybrid Supercapacitor.

Author

He, Mingliang, Qiao, Jia, Zhou, Binghua, Wang, Jie, Guo, Shien, Melvin, Gan Jet Hong, Wang, Mingxi, Ogata, Hironori, Kim, Yoong Ahm, Tanemura, Masaki, Wang, Shuwen, Terrones, Mauricio, Endo, Morinobu, Zhang, Fei, and Wang, Zhipeng

Subjects
LAYERED double hydroxides, CARBON fibers, ELECTRON density, ENERGY density, ELECTRIC conductivity
Abstract

Layered double hydroxide (LDH) is considered a highly promising electrode material for supercapacitors (SCs) due to its high theoretical specific capacitance. However, LDH powders often suffer from poor electrical conductivity, structure pulverization, slow charge transport, and insufficient active sites. Herein, a self‐supporting electrode with a Mott–Schottky heterostructure has been designed for high‐performance SCs. The electrode consists of low crystallinity NiCo‐LDH nanosheets and vertical graphene (VG) directly grown on carbon cloth. The LDH was converted from a metal–organic framework (MOF) by the sol–gel method. This self‐supporting electrode provides fast charge transfer, reducing the pulverization effect and energy barrier. The Mott–Schottky heterostructure of LDH@VG regulates electron density and enhances electron transfer, as confirmed by density functional theory calculation. The optimized LDH@VG heterostructure electrode exhibits an excellent areal capacitance of 5513.8 mF cm−2 and rate capability of 82.1%. Furthermore, the fabricated hybrid SC demonstrates excellent energy density of 404.8 μWh cm−2 at 1.6 mW cm−2 and a remarkable cycling life, with a capacitance of 92.0% after 10 000 cycles. This work not only provides a simple dip‐coating and MOF conversion method to synthesize heterojunction‐based electrodes, but also broadens the horizon for designing advanced electrode materials for SCs. [ABSTRACT FROM AUTHOR]

Published
2024
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30. Plasma-induced N doping and carbon vacancies in a self-supporting 3C-SiC photoanode for efficient photoelectrochemical water oxidation.

Author

Wu, Linyi, Guan, Shuchang, Zhou, Binghua, Guo, Shien, Wang, Jie, Wu, Ling, Hong Melvin, Gan Jet, Ortiz-Medina, Josue, Wang, Mingxi, Ogata, Hironori, Tanemura, Masaki, Kim, Yoong Ahm, Terrones, Mauricio, Endo, Morinobu, and Wang, Zhipeng

Abstract

Due to its suitable bandgap and excellent stability, 3C-SiC is being investigated as one of the promising candidates for photoelectrochemical (PEC) water oxidation. However, the limited surface activity and short carrier lifetime prevent 3C-SiC photoanodes from facilitating efficient PEC water splitting. To tackle these problems, this work proposes a plasma technique to control the crystal structure and optical characteristics of 3C-SiC. Nitrogen plasma induces carbon vacancies (Vc) and Si–N bonds, further leading to a narrower bandgap of 3C-SiC. The combination of Vc and N doping enhanced the light trapping capability of the electrode, thereby improving the efficiency of electron–hole pair separation and charge transfer, resulting in an accelerated water oxidation reaction, i.e., photocurrent density (2.50 mA cm−2 at 1.23 VRHE) increased by 7.6 times compared to that of pristine SiC. This work offers an effective strategy for regulating the electronic structure of SiC-based photoanodes by plasma treatment, which may be extended to other photoelectrodes for PEC application. [ABSTRACT FROM AUTHOR]

Published
2024
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