Sonochemical versus hydrothermal synthesis of bismuth tungstate nanostructures: Photocatalytic, sonocatalytic and sonophotocatalytic activities

In the present work, an ultrasound-assisted hydrothermal method was applied as a new approach for the synthesis of Bi₂WO₆ nanostructures. In sonication, a cup horn system as an indirect high intensity sonicator was used. To determine the influence of ultrasonic waves on the morphology, Bi₂WO₆ was also synthesized using the hydrothermal method. The conventional and sonochemical products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), Raman, photoluminescence (PL), and UV-Vis (UV-Vis) spectroscopies. The XRD patterns confirmed that the sonosynthesized sample has higher crystallinity than the conventional one. The results also showed that ultrasound decreased the particle size and improved the size distribution. In comparison with the hydrothermal sample, the flower like structures formed under sonication have many hollow sites, resulting in higher harvesting and scattering of visible light. The efficiency of resulting nanoparticles in degradation of a binary mixture (RhB/MB) as pollutant was evaluated by photocatalytic, sonocatalytic, and sonophotocatalytic processes. The sono-synthesized sample removed the pollutants four times faster than the hydrothermal sample in sonophocatalytic process. Besides, determining factors including pH, pollutant concentration, temperature, and ultrasound amplitude were optimized in the sonophotocatalytic process.

Influence of cobalt substitution on the crystal structure, band edges and photocatalytic properties of hierarchical Bi2WO6 microspheres

An efficient Bi₂WO₆ catalyst with Co²⁺ substitution was synthesized via a facile hydrothermal route.

Single-Pot Synthesis of ⟨001⟩-Faceted N-Doped Nb2O5/Reduced Graphene Oxide Nanocomposite for Efficient Photoelectrochemical Water Splitting

Due to exciting catalytic activity and selectivity, tailoring of nanocatalysts consisting of preferred crystal facets and desired structural properties remains at the forefront of materials engineering. A facile one-step nonhydrolytic solvothermal synthesis of a nanocomposite of reduced graphene oxide and one-dimensional nitrogen-doped Nb2O5 (N-NbOx) with exposed ⟨001⟩ facet is described. Triethylamine performed the dual role as nitrogen source and capping agent to control the size and unidirectional growth of Nb2O5 nanocrystallites. The nanocomposite showed efficient visible-light-mediated (λ > 420 nm) water splitting in a photoelectrochemical cell. A plausible mechanism for the formation of N-NbOx nanorods and improved photoelectrochemical efficacy in terms of their oriented growth is proposed.

Facet-dependent photocatalytic and antibacterial properties of α-Ag2WO4crystals: combining experimental data and theoretical insights

We have combined experimental results and calculations with new paths to explain the photocatalytic and antibacterial activities of α-Ag₂WO₄crystals.

One-step electrochemical synthesis of Bi3.84W0.16O6.24 with superior photocatalytic activities

Bi_3.84W_0.16O_6.24 nanoparticles were successfully prepared by a facile electrochemical route at room temperature in just 10 minutes.

Hydrothermal synthesis of CaIn2S4-reduced graphene oxide nanocomposites with increased photocatalytic performance

A series of CaIn2S4-reduced graphene oxide (RGO) nanocomposites with different RGO contents were fabricated using a facile hydrothermal approach. During the hydrothermal process, the reduction of graphene oxide to RGO, in situ deposition of synthesized CaIn2S4 nanoparticles on RGO nanosheets and formation of chemical-bonding CaIn2S4-RGO nanocomposites were performed simultaneously. Under visible light irradiation, the as-prepared CaIn2S4-RGO nanocomposites showed enhanced photocatalytic performance for rhodamine B degradation and phenol oxidation. The sample with 5 wt % RGO hybridized CaIn2S4 exhibited the highest photocatalytic activity. The enhancement of photocatalytic performance may be related to the increased adsorption/reaction sites, positive shift of the valence band potential, and high separation efficiency of photogenerated charge carriers due to the electronic interaction between CaIn2S4 and RGO. We hope that this work can not only provide an in-depth study on the photocatalytic mechanism of RGO-enhanced activity, but also provide some insights for fabricating efficient and stable RGO-based photocatalysts in the potential applications of purifying polluted water resources.

Visible light-driven photocatalytic and photoelectrochemical studies of Ag–SnO2 nanocomposites synthesized using an electrochemically active biofilm

Ag–SnO₂ nanocomposites (1 mM and 3 mM) were synthesized in water at room temperature using an electrochemically active biofilm.