A significant challenge in developing high-performance hybrid supercapacitors (HSCs) is the need to reasonably construct advanced architectures that consist of various components and exhibit superior electrochemical capacitance performance. The FeCoNi-layered double hydroxide (FeCoNi-LDH) porous material has a specific capacitance of 1960 F·g −1 when used as the anode material at 1 A·g −1 . The FeCoNi-LDH material exhibits nanoplates with a distinct spindle morphology on their surface. Due to the combined action of the three metals and abundant oxygen vacancies, they exhibit unique rate performance and cycle stability. The electronic structure of LDH and the regulation of oxygen vacancy were confirmed by density functional theory (DFT) calculations. This suggests that the strength of hydroxide can reduce the energy required for oxygen vacancy formation in FeCoNi-LDH nanosheets and enhance ion and charge transfer, as well as electrolyte adsorption on the electrode surface. The FeCoNi-LDH//activated carbon (AC) HSC has an energy density of 53.2 Wh·kg −1 at a power density of 800 W·kg −1 , surpassing other devices composed of comparable materials during the same timeframe. This study made significant advances in the design and synthesis of a ternary LDH porous structure with distinct oxygen vacancies, as well as its potential application in electrochemical energy storage.
Xuan Liu,Zi-yu Zheng,Xuan Wang,Hao-rui Gao,Jia-qian Niu,Shi-qi Li,Yue-qin Duan,Xue-wei Wang
Improvement of catalyst dispersion is an effective strategy for performance enhancement of electrocatalytic oxygen evolution reaction (OER), while the heterogeneous structure can also regulate the electronic structure of the catalyst interface. In this paper, Cu 2 S nanorods were synthesized in situ on copper foam (CF) by alkaline etching and sulfidation, Subsequently, FeCoNi LDH nanosheets were electrodeposited on Cu 2 S nanorods to construct FeCoNi LDH/Cu 2 S heterojunctions. The electrochemical results demonstrate that FeCoNi LDH/Cu 2 S/CF exhibits high efficiency as an alkaline OER electrocatalyst with an overpotential of 211 mV at a current density of 100 mA cm −2 . Furthermore, FeCoNi LDH/Cu 2 S/CF can operate for 30 h and shows good cycling stability. The XPS results indicate that the electrons are transferred from FeCoNi LDH to Cu 2 S. The formation of the FeCoNi LDH/Cu 2 S heterojunction optimizes the interface at the heterojunction, thereby accelerating the electron transfer and optimizing the electronic structure at the interface. The uniform dispersion of FeCoNi LDH provides a high density of active sites and improves the mass transfer ability, thus enhancing the catalytic performance. This experimental strategy presents a generalized approach to improve the efficient electrochemical reaction of layered double hydroxides.
Zi-yu Zheng,Xue-wei Wang,Yi-fan Zhang,Jia Li,Xiao Li,Wen-hua Zhang,Xuan Li
Constructing heterojunction is a good method to improve electrocatalytic activity because the heterojunctions can modulate the Fermi level and redistribute charges of the catalysts to accelerate electron transfer . In this study, Ni 3 S 2 nanocones were prepared on nickel foam (NF) by hydrothermal synthesis, and FeCoNi LDH/Ni 3 S 2 Schottky heterojunctions were constructed by electrodeposition of FeCoNi LDH nanosheets onto Ni 3 S 2 nanocones. Electrochemical results demonstrate that FeCoNi LDH/Ni 3 S 2 /NF is an efficient alkaline OER catalyst, the overpotential is 216 mV at 100 mA cm -2 , and it can maintain stable operation for 110 h. The battery voltage of the dual-electrode structure composed of FeCoNi LDH/Ni 3 S 2 /NF and NF at 1 M KOH is 1.61 V at 10 mA cm -2 . The results of XPS show that the FeCoNi LDH/Ni 3 S 2 Schottky heterojunction optimizes the electronic structure of the interface, accelerating electron transfer. Additionally, the enhanced electric field effect at the tip of Ni 3 S 2 further promotes electron transfer in the heterojunction structure. FeCoNi LDH/Ni 3 S 2 Schottky heterojunction exhibits significant OER activity, which provides a method for synthesizing transition metal heterojunction catalysts with low cost and high activity in the future.
Jiali Chen,Lijuan Chen,Yuanzhao Huang,Jin Su,Fan Chen,Wei Wang
The excessive reliance on traditional fossil fuels has not only triggered an energy shortage crisis but also caused severe environmental pollution. These pollutants can significant accumulate via the process of bioaccumulation within the food chain, ultimately posing a serious threat to human health. Therefore, the development of efficient and precise water quality monitoring technologies is crucial for the prevention and control of environmental pollution. In this study, a g-C 3 N 4 -FeCoNi layered double hydroxide (LDH) heterostructure material (g-C 3 N 4 -LDH) was successfully synthesized using a one-step hydrothermal method. The formation of an n–n heterojunction between g-C 3 N 4 and LDH facilitates efficient interfacial charge transfer and structural stabilization, which is critical for bifunctional applications. Consequently, the constructed g-C 3 N 4 -LDH sensing platform exhibits good performance in 4-NP detection, with a sensitivity of 0.664 μA·μM −1 ·cm −2 , a linear response range of 5–800 μM, and a low detection limit of 0.67 μM (S/N = 3). Moreover, the platform demonstrates strong resistance to interference and excellent stability. Additionally, g-C 3 N 4 -LDH can completely degrade 4-NP within 10 min, effectively detoxifying the pollutants. This study offers new insights and a solid foundation for the rapid and accurate detection and treatment of water pollutants.
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