Yun Zhou,Qiujie Ding,Yuan Wang,Xiaoping OuYang,Lixin Liu,Junyu Li,Bing Wang
In this paper, TiO2/Ag2V4O11nanoheterojunctions have been synthesized by hydrothermal methods, which show enhanced photocatalytic activity compared to TiO2under visible light. Moreover, the TiO2/Ag2V4O11nanoheterojunction with set molar ratio of 2:1, referred to as TA2, show the highest visible light photocatalytic activity, which could decompose about 100% RhB molecules within 80 min of irradiation with visible light. Specially, the time-resolved photoluminescence spectrum of TA2 demonstrates that the free exciton recombination occurs in approximately 1.7 ns, and the time scale for Shockley–Read–Hall recombination of photogenerated electrons and holes is prolonged to 6.84 ns. The prolonged timescale of TA2 compared to TiO2and Ag2V4O11can be attributed to the carrier separation between nanojunctions and the carrier capture by interfacial defects. Furthermore, the enhanced photocatalytic activity of TiO2/Ag2V4O11nanoheterojunctions also benefits from the synergistic effect of the broadened absorption region, higher photocarrier generation, longer carrier lifetime, and quicker collection dynamics.Keywords:TiO2/Ag2V4O11;nanoheterojunctions;photocatalyst;interface effect;carrier capture;recombination kinetics
Sun Liping,Shen Hengxia,Zheng Laibao,Gao Ping,Xiang Zhenbo
A colorimetric, rapid, and effective method for uric acid (UA) detection based on Ag 2 V 4 O 11 nanobelts has been developed. Ag 2 V 4 O 11 nanobelts were synthesized by a straightforward hydrothermal process, and proved to possess intrinsic peroxidase-like activity. The kinetic analysis illustrated that the reaction catalyzed by Ag 2 V 4 O 11 nanobelts followed typical Michaelis–Menten kinetics. The results of active species trapping experiments suggested that superoxide radical (·O 2 − ) played an important role in the reaction. The developed UA detection method showed a linear relationship from 1 μM to 110 μM with a detection limit of 0.35 μm. The results of selective experiments indicated that the method has a satisfactory detection selectivity on UA. Finally, the method was applied in the determination of UA in human serum, and the results were extremely close to the hospital results. This work would be indicative for the construction of Ag 2 V 4 O 11 nanobelts in the application of UA determination. Graphic Abstract Schematic illustration of the colorimetric method for UA determination.
One of the hottest research topics at present is the construction of environmentally friendly and secure aqueous zinc-ion batteries (AZIBs) using an aqueous electrolyte instead of an organic electrolyte. As a result of their diverse structure, valence state, high theoretical specific capacity, and other benefits, vanadium-based materials, which are frequently employed as the cathode of AZIBs, have drawn the attention of many researchers. The low cycle stability of zinc ion batteries (ZIBs) is mostly caused by the disintegration of the vanadium-based cathode materials during continuous charge and discharge. In this work, using 3M Zn(CF3SO3)2as the electrolyte and hydrothermally synthesized Ag2V4O11as the cathode material, the high-rate performance and extended cycle life of ZIBs were evaluated. The effects of different hydrothermal temperatures on the microstructure, capacity, and cycle stability of the Ag2V4O11cathode material were examined. The experimental results show that Ag2V4O11exhibits a typical intercalation-displacement process when used as the cathode material. The multiplicative performance and cycle stability of the cathode material were significantly enhanced at a hydrothermal temperature of 180 °C. Ag2V4O11-180 has a high discharge specific capacity of 251.5 mAh·g−1at a current density of 0.5 A·g−1and a long cycle life (117.6 mAh·g−1after 1000 cycles at a current density of 3 A·g−1). According to the electrochemical kinetic investigation, the cathode material has a high pseudocapacitive charge storage and Zn2+diffusion coefficient. This is attributed to the large layer spacing and the Ag+anchored interlayer structure.
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