3D Bi2MoO6 Microspheres Research Articles

A Novel Non-Enzymatic Sensor Based on Bismuth Molybdate @polydopamine-Gold Nanocomposites for Efficient Nitrite Sensing

Novel Bismuth molybdate@polydopamine-Au nanocomposites (Bi2MoO6@PDA-Au) were synthesized and used to construct a sensor for enhanced electrochemical determination of nitrite (NO2 −). Bi2MoO6@PDA-Au was investigated with scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and the results showed a large number of Au nanoparticles were uniformly distributed on 3D Flowerlike Bi2MoO6 microspheres coated with PDA. Electrochemical techniques were employed to study electrochemical performance, and the results revealed that the sensor has an excellent response to NO2 − with a comprehensive linear range of 0.3 μM to 4.4 mM, which is an order of magnitude wider than that obtained by the CQD-PEDOT/GCE and two orders of magnitude wider than that obtained by the Au-MoS2/GCE. In addition, the sensor also displayed good reproducibility, reusability, long-termstability, fast response time, and anti-interference performance. It is expected that Bi2MoO6@PDA-Au nanocomposites could be a promising material in the practical efficient detection of NO2 −.

Microwave-assisted synthesis of 3D Bi2MoO6 microspheres with oxygen vacancies for enhanced visible-light photocatalytic activity.

Oxygen vacancies (OVs) defects in metal oxide-based photocatalysts play a crucial role in improving the charge carrier separation efficiencies to enhance the photocatalytic performances. In this work, OVs were introduced in 3D Bi2MoO6 microspheres through a facile and fast microwave-assisted method via the modulation of tetramethylethylenediamine (TMEDA). EPR, Raman and XPS results demonstrated that large amounts of oxygen vacancies were formed on the surface of BMO microspheres. The photocatalytic properties of the samples were studied by degradation of tetracycline (TC) under visible light. The optimal Bi2MoO6 with OVs exhibited optimum photocatalytic activity, and the degradation rate was 7.0 times higher than that of pristine Bi2MoO6. This enhancement can be attributed to the 3D structure furnishing more surface active sites and suitable OVs defects favoring the electron-hole separation. Moreover, the defective Bi2MoO6 microspheres exhibit high stability because the photocatalytic activity remains almost unchanged after 5 cycles, making them favorable for practical applications. Finally, a possible visible light photocatalysis mechanism for the degradation of TC was tentatively proposed.

Microwave Solvothermal Synthesis of Three-Dimensional Bi2MoO6 Microspheres with Enhanced Photocatalytic Activity.

In this study, three-dimensional (3D) Bi2MoO6 microspheres were successfully fabricated by a facile, rapid, and mild microwave solvothermal strategy for the first time. The resultant 3D Bi2MoO6 microspheres exhibited superior adsorption capacity and photocatalytic efficiency in the degradation of the representative antibiotic ciprofloxacin under visible light, for which the reaction kinetic rate constant is 7.5 times as high as that of the as-synthesized zero-dimensional Bi2MoO6 nanoparticles. The 3D hierarchical porous structure and the high Brunauer–Emmett–Teller surface area providing abundant reactive sites mainly contributed to the enhanced photocatalytic activity. The results highlight the feasibility of 3D Bi2MoO6 microspheres as an efficient visible-light-responsive photocatalyst for antibiotic removal in an aqueous system.

Photocatalytic Reduction of CO2 to CO over 3D Bi2MoO6 Microspheres: Simple Synthesis, High Efficiency and Selectivity, Reaction Mechanism

It has been a promising approach for directly utilizing solar energy to convert CO2 into clean renewable chemical fuels over photocatalysts with excellent photoreactivity, CO2 adsorption capacity and reasonable redox potentials. In this work, as-synthesized 3D Bi2MoO6 microspheres with cross-stacking nanosheets via a simple hydrothermal method have been investigated for photocatalytic CO2 reduction, and characterized by XRD, UV–Vis DRS, SEM, HRTEM and BET. It was found that as-prepared samples exhibited high Bi2MoO6 purity, large specific surface area, excellent light response and CO2 adsorption capacity, achieving superior photocatalytic CO2 reduction activity and selectivity of CO yield (41.5 μmol g−1 h−1). Moreover, the photocatalytic reaction mechanism for CO2 reduction to CO over 3D Bi2MoO6 microspheres was investigated and proposed. Finally, COOH* was verified to be a key intermediate for photocatalytic CO2 reduction to CO by the analysis of in-situ FTIR. Our findings should provide excellent foundation and guidance for boosting photocatalytic CO2 conversion to CO with enhanced effective and selective ability. 3D Bi2MoO6 microspheres with cross-stacking nanosheets exhibit large specific surface area, excellent light response and CO2 adsorption capacity. COOH*, as a key reaction intermediate, can significantly reduce the activation energy of CO2.

Alkali-assisted synthesis of direct Z-scheme based Bi2O3/Bi2MoO6 photocatalyst for highly efficient photocatalytic degradation of phenol and hydrogen evolution reaction

Semiconductor based photocatalytic technology has attracted substantial research attention based on its potential to overcome environmental and energy crisis. The conventional photocatalysts with their issues such as rapid charge recombination are considered unfavorable candidates for practical applications. Herein, a novel direct Z-scheme based photocatalyst composed of Bi2O3/Bi2MoO6 hetrojunction is proposed for efficient photo-degradation of phenol and hydrogen (H2) production reaction. The hetrojunction comprises of ultra-thin (2D) Bi2O3 nanosheets, in-situ grown over 3D Bi2MoO6 microspheres via simple alkali treatment of Bi2MoO6 succeeded by air calcination step. The relative mass ratio of Bi2O3 and Bi2MoO6 could be fine-tuned by controlling the alkali dosage (i.e. NaOH or KOH). Unlike the conventional Bi2O3/Bi2MoO6 hetrojunction, the proposed catalyst follow a direct Z-scheme charge transfer mechanism which permits superior photocatalytic activity with 96.4% phenol degradation efficiency and high hydrogen evolution rate of 52 μmol·g−1 under visible light irradiation. The exuberant performance is accredited to the spatially separated redox charge carriers, excellent light harvesting capability and fast-charge transportation characteristics of the proposed photocatalyst. The present work serves as a primary pathway to design and develop efficient Bi2MoO6-based direct Z-scheme photocatalysts with promising applications in environmental remediation and solar fuel production.

Preparation and characterization of Fe3O4/SiO2/Bi2MoO6 composite as magnetically separable photocatalyst

In this paper, Fe3O4/SiO2/Bi2MoO6 microspheres were prepared by a facile hydrothermal method. The scanning electron microscope (SEM) results revealed that flower-like three dimensional (3D) Bi2MoO6 microspheres were decorated with Fe3O4/SiO2 magnetic nanoparticles. The UV–vis diffuse reflection spectra showed extended absorption within the visible light range compared with pure Bi2MoO6. We evaluated the photocatalytic activities of Fe3O4/SiO2/Bi2MoO6 microspheres on the degradation of Rhodamine B (RhB) under visible light irradiation and found that the obtained composite exhibited higher photocatalytic activity than pure Bi2MoO6 and P25. Moreover, the Fe3O4/SiO2/Bi2MoO6 composite also displayed excellent stability and their photocatalytic activity decreased slightly after reusing 5cycles. Meanwhile, the composite could be easily separated by applying an external magnetic field. The trapping experiment results suggest that superoxide radical species O2− and hydroxyl radicals OH play a major role in Fe3O4/SiO2/Bi2MoO6 system under visible light irradiation. The combination of flower-like three dimensional (3D) Bi2MoO6 microspheres and Fe3O4/SiO2 magnetic nanospheres provides a useful strategy for designing multifunctional nanostructure materials with enhanced photocatalytic activities in the potential applications of water purification.