Preparation and Characterization of Mo Doped in BiVO4 with Enhanced Photocatalytic Properties

Molybdenum (Mo) doped BiVO4 was fabricated via a simple electrospun method. Morphology, structure, chemical states and optical properties of the obtained catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), N2 adsorption–desorption isotherms (BET) and photoluminescence spectrum (PL), respectively. The photocatalytic properties indicate that doping Mo into BiVO4 can enhance the photocatalytic activity and dark adsorption ability. The photocatalytic test suggests that the 1% Mo-BiVO4 shows the best photocatalytic activity, which is about three times higher than pure BiVO4. Meanwhile, 3% Mo-BiVO4 shows stronger dark adsorption than pure BiVO4 and 1% Mo-BiVO4. The enhancement in photocatalytic property should be ascribed to that BiVO4 with small amount of Mo doping could efficiently separate the photogenerated carries and improve the electronic conductivity. The high concentration doping would lead the crystal structure transformation from monoclinic to tetragonal phase, as well as the formation of MoO3 nanoparticles on the BiVO4 surface, which could also act as recombination centers to decrease the photocatalytic activity

Dendritic WS₂ nanocrystal-coated monolayer WS₂ nanosheet heterostructures for phototransistors

Two-dimensional tungsten disulfide (WS2), as one of the widely concerned members of the transition metal dichalcogenides family, has been studied broadly by its outstanding photonic and electronic properties. Since all of the research works focus on size and the number of layers, the dendritic structure WS2 has been scarcely reported. In our study, we make use of atmospheric pressure chemical vapor deposition (APCVD) to control the synthesis of dendritic WS2/monolayer WS2 heterostructures on the SiO2/Si substrate. The stacking morphology of the heterostructure is verified by AFM, Raman, and PL spectra. The effects of growth times and carrier gas flux on the quasi-epitaxial growth of WS2 films with dendritic structures have been systematically studied. In addition, the transition between fractal, dendritic, and compact morphologies with the increase of the growth times (carrier gas flux) are more significant. The compact morphology and difference of contact potential between the adjacent dendritic structures are characterized by Kelvin probe force microscopy (KPFM). Moreover, the as-fabricated FET devices exhibit excellent electronic properties (on/off ratio, carrier mobility, photoresponsivity, and response time are about 106, 11.42 cm2 V-1S1-, 46.6 mA/W, and 105.5 μs, respectively). This study paves the way for the rational design of high-sensitivity fractal-enhanced phototransistor devices for industrial and commercial applications.The authors are grateful for the financial support from the Science and Technology Service Network Initiative of the Chinese Academy of Sciences (Nos. KFJ-STS-QYZD-179 and KFJ-STS-QYZD-123), State Key Laboratory of Luminescence and Applications (NO. SKLA-2021-03), and commercial research funds (No. Y79H030)

Sensitive Nonenzymatic Electrochemical Glucose Detection Based on Hollow Porous NiO

Abstract Transition metal oxides (TMOs) have attracted extensive research attentions as promising electrocatalytic materials. Despite low cost and high stability, the electrocatalytic activity of TMOs still cannot satisfy the requirements of applications. Inspired by kinetics, the design of hollow porous structure is considered as a promising strategy to achieve superior electrocatalytic performance. In this work, cubic NiO hollow porous architecture (NiO HPA) was constructed through coordinating etching and precipitating (CEP) principle followed by post calcination. Being employed to detect glucose, NiO HPA electrode exhibits outstanding electrocatalytic activity in terms of high sensitivity (1323 μA mM−1 cm−2) and low detection limit (0.32 μM). The excellent electrocatalytic activity can be ascribed to large specific surface area (SSA), ordered diffusion channels, and accelerated electron transfer rate derived from the unique hollow porous features. The results demonstrate that the NiO HPA could have practical applications in the design of nonenzymatic glucose sensors. The construction of hollow porous architecture provides an effective nanoengineering strategy for high-performance electrocatalysts

Additional file 1: of Sensitive Nonenzymatic Electrochemical Glucose Detection Based on Hollow Porous NiO

Supplementary figures and tables. (DOC 6924 kb