Structural regulation is an effective strategy for enhancing an electrode's energy storage performance. Herein, lignin-derived carbon dots (LCDs) are explored for the structural tailoring of NiSe/MnO2 to improve the electrochemical performance in supercapacitors. After the dendritic NiSe microcrystals are synthesized via a microwave method, NF/NiSe/MnO2-LCDs are prepared by another microwave process to form a composite mixture of LCDs, MnO2, and NF/NiSe. At 1 A g–1, NF/NiSe/MnO2-LCDs possess a specific capacitance of 2268 F g–1 and superb lifespans (84.43%, 3000 cycles) for their enhanced ion transport and rapid electron transfer. In addition, the NF/NiSe/MnO2-LCDs//AC ASC showed an energy density of 51.62 Wh kg–1 at 800 W kg–1 and extraordinary endurance with 88.46% retention (7000 loops). The NF/NiSe/MnO2-LCDs offer ideas to improve the capacity retention and storage capacity of electrodes for supercapacitors.
Wenlong Zhen,Xiaofeng Ning,Meng Wang,Yuqi Wu,Gongxuan Lu
CdS is a promising visible-light responsive photocatalyst. However, the serious photocorrosion limits its application in photocatalysis. Here we report a novel strategy to overcome the disadvantage of CdS photocorrosion by fabricating peroxide decomposing active MnO 2 thin-layer over CdS nanowires (NWs) and assembling oxygen separation artificial gill to remove nascent formed oxygen in the dispersion. In the meantime, the using non-noble metal NiSe quantum dots (QDs) co-catalyst, NiSe/MnO 2 -CdS photocatalysts shows excellent photocatalytic over-all water splitting activity and remarkable stability under visible light irradiation without addition of any sacrifice reagent, 455.0 µmol h −1 g −1 of hydrogen evolution reaction (HER) rate and 5.20% of apparent quantum efficiency (AQEs) at 430 nm. Removing nascent formed O 2 from water by artificial gill can prevent the oxygen leading CdS photocorrosion. Photoluminescence spectra and photoelectrochemical measurements indicate that loading NiSe QDs and coating MnO 2 thin-layer can also improve transfer of the photogenerated charges in CdS. MnO 2 thin-layer can decompose formed hydrogen peroxide and enhance water splitting. Our results could potentially provide a new method for designing and fabricating more stable and efficient CdS-based nanocomposite photocatalysts toward versatile solar energy conversion.
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