Synergistic Effect of Amorphous Ti(IV)-Hole and Ni(II)-Electron Cocatalysts for Enhanced Photocatalytic Performance of Bi2WO6

Bi2WO6 has become a common photocatalyst due to its advantages of simple synthesis and high activity. However, the defects of pure Bi2WO6 such as low light reception hinder its application in photocatalysis. In this study, based on the modification of Bi2WO6 with Ti(IV) as a cavity co-catalyst, new Ni- and Ti-doped nanosheets of Bi2WO6 (Ni/Ti-Bi2WO6) were prepared by a one-step wet thermal impregnation method and used for the photocatalytic degradation of tetracycline. The experimental results showed that the photocatalytic activity of Ni/Ti-Bi2WO6 modified by the two-component catalyst was significantly better than those of pure Bi2WO6 and Ti-Bi2WO6 modified with Ti(IV) only. The photocatalytic effect of Ni/Ti-Bi2WO6 with different Ni/Ti molar ratios was investigated by the degradation of TC. The results showed that 0.4Ni/Ti-Bi2WO6 possessed the best photocatalytic performance, with a degradation rate of 92.9% at 140 min TC. The results of cycling experiments showed that the catalyst exhibited high stability after five cycles. The scavenger experiment demonstrated that the h+ and O2− were the main reactive species. The enhanced photocatalytic activity of Bi2WO6 could be attributed to the synergistic effect between the Ti(IV) as a hole cocatalyst and Ni(II) as an electron cocatalyst, which effectively promoted the separation of photogenerated carriers.

Polaron formation and transport in Bi2WO6 studied by DFT+U and hybrid PBE0 functional approaches

Bi₂WO₆ (BWO) is considered as a promising material for photocatalytic water splitting. Its unique layered structure leads the charge separation, and transport is different from other materials. However, the charge transport mechanisms in BWO are not well understood. In this work, we investigated polaron formation and transport in BWO using the DFT+U and hybrid PBE0 functional approaches. We found that the electron will form 2-dimensional (2D)-shaped polarons among W sites in the ab plane of BWO with approximately 55% polaron density state on the central W site. This type of polaron is similar to the electron polarons in WO₃. For other W-based materials, the electrons may also form a 2D-shaped polaron. We found that the W 6s orbital plays an important role in these 2D-shaped electron polarons. The calculated mobility of electron polarons in BWO was consistent with experimental findings. For the hole state, it could form a small hole polaron on the O site with O 2p in character. However, it will not form a polaron on the Bi site, which is quite different from BiVO₄. This study provides insight for understanding polaron formation and transport in materials with W and Bi ions. It also provides understanding regarding charge separation and transport for materials with layered structures.

Photochemical deposition of amorphous MoSx on one-dimensional NaNbO3–CdS heterojunction photocatalysts for highly efficient visible-light-driven hydrogen evolution

A novel ternary MoS_x–CdS–NaNbO₃ (MoS_x–CN) photocatalyst was successfully fabricated through a two-step method (hydrothermal synthesis and photo-deposition step).

Enhanced photocatalytic activity of Bi2WO6 for the degradation of TC by synergistic effects between amorphous Ti and Ni as hole–electron cocatalysts

The possible mechanism of photocatalytic degradation of TC by Ni/Ti-Bi₂WO₆ under visible light.

CO2 photoreduction to CO/CH4 over Bi2W0.5Mo0.5O6 solid solution nanotubes under visible light

In this work, Bi₂W_0.5Mo_0.5O₆ solid solution nanotubes have been synthesized through a structure-directing hard template approach, which demonstrated greatly enhanced CO₂ photoreduction to CO/CH₄. The crystalline phase, components and morphologies of the as-prepared composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The present design of Bi₂W_0.5Mo_0.5O₆ solid solution nanotubes leads to remarkably enhanced photocatalytic activities with a peak CO/CH₄ production rate of 6.55/3.75 mmol g⁻¹ h⁻¹ under visible light irradiation at room temperature, which was about 7 times that on pure Bi₂WO₆ and Bi₂MoO₆ nanotubes, respectively. Hollow nanotubular structures and synergistic electronic effects of various elements contribute to the enhanced visible light photocatalytic activity of Bi₂W_0.5Mo_0.5O₆ solid solution nanotubes.

In this work, Bi₂W_0.5Mo_0.5O₆ solid solution nanotubes have been synthesized through a structure-directing hard template approach, which demonstrated greatly enhanced CO₂ photoreduction to CO/CH₄.

Nanoplasmonically Engineered Interfaces on Amorphous TiO2 for Highly Efficient Photocatalysis in Hydrogen Evolution

The nanoplasmonic metal-driven photocatalytic activity depends heavily on the spacing between metal nanoparticles (NPs) and semiconductors, and this work shows that ethylene glycol (EG) is an ideal candidate for interface spacer. Controlling the synthetic systems at pH 3, the composite of Ag NPs with EG-stabilized amorphous TiO₂ (Ag/TiO₂-3) was synthesized by the facile light-induced reduction. It is verified that EG spacers can set up suitable geometric arrangement in the composite: the twin hydroxyls act as stabilizers to bind Ag NPs and TiO₂ together and the nonconductive alkyl chains consisting only of two CH₂ are able to separate the two building blocks completely and also provide the shortest channels for an efficient transfer of radiation energies to reach TiO₂. Employed as photocatalysts in hydrogen evolution under visible light, amorphous TiO₂ hardly exhibits the catalytic activity due to high defect density, whereas Ag/TiO₂-3 represents a remarkably high catalytic efficiency. The enhancement mechanism of the reaction rate is proposed by the analysis of the compositional, structural, and optical properties from a series of Ag/TiO₂ composites.

A systematic study on polymerization and photocatalytic performance by investigating Ag2O·x(MoO3) (x = 1, 2, 3, 4) photocatalysts

Polymerized Ag₂O·x(MoO₃) samples showed superior photocatalytic performance, and polymerization could be a potential strategy to enhance the photocatalytic activity.

A novel Nb2O5/Bi2WO6 heterojunction photocatalytic oxidative desulfurization catalyst with high visible light-induced photocatalytic activity

A novel Nb₂O₅/Bi₂WO₆ heterojunction catalyst was synthesized and applied in PODS of DBT. It shows higher activity than pure Nb₂O₅ and Bi₂WO₆ in visible light induced PODS of DBT, in which holes and superoxide radicals are the main reactive species.

One-pot preparation of Bi/Bi2WO6/reduced graphene oxide as a plasmonic photocatalyst with improved activity under visible light

The Bi/Bi₂WO₆/rGO nanocomposite for simultaneous RhB adsorption and photocatalysis was synthesized by a one-pot hydrothermal method.