Construction of the Photocatalytic Film of the Recyclable TaON/Nickel Foam with Ohmic Junction for Efficient Wastewater Treatment

A recyclable photocatalytic film of TaON/Ni foam with ohmic junction is prepared by the electrophoretic deposition technology. The photocatalytic film of 60 mg TaON/Ni foam demonstrates excellent photocatalytic activity and recycling performance for the degradation of basic fuchsin from water. Around 80% of basic fuchsin (50 mL, 10 mg L−1) is removed over 60 mg TaON/Ni foam under irradiation of 72 W LED white light for 5 h. The photocatalytic activity of the film does not significantly decrease after three rounds of use. The active species for the photocatalytic degradation of basic fuchsin are ·O2−, h+ and ·OH.

Zinc Tantalum Oxynitride (ZnTaO₂N) Photoanode Modified with Cobalt Phosphate Layers for the Photoelectrochemical Oxidation of Alkali Water

Photoanodes fabricated by the electrophoretic deposition of a thermally prepared zinc tantalum oxynitride (ZnTaO₂N) catalyst onto indium tin oxide (ITO) substrates show photoactivation for the oxygen evolution reaction (OER) in alkaline solutions. The photoactivity of the OER is further boosted by the photodeposition of cobalt phosphate (CoPi) layers onto the surface of the ZnTaO₂N photoanodes. Structural, morphological, and photoelectrochemical (PEC) properties of the modified ZnTaO₂N photoanodes are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet visible (UV−Vis) diffuse reflectance spectroscopy, and electrochemical techniques. The presence of the CoPi layer significantly improved the PEC performance of water oxidation in an alkaline sulphate solution. The photocurrent-voltage behavior of the CoPi-modified ZnTaO₂N anodes was improved, with the influence being more prominent at lower oxidation potentials. A stable photocurrent density of about 2.3 mA·cm⁻² at 1.23 V vs. RHE was attained upon visible light illumination. Relative to the ZnTaO₂N photoanodes, an almost three-fold photocurrent increase was achieved at the CoPi/ZnTaO₂N photoelectrode. Perovskite-based oxynitrides are modified using an oxygen-evolution co-catalyst of CoPi, and provide a new dimension for enhancing the photoactivity of oxygen evolution in solar-assisted water-splitting reactions.

Synthesis of single-crystalline, porous TaON microspheres toward visible-light photocatalytic conversion of CO2 into liquid hydrocarbon fuels

The porous spherical architecture of TaON plays a significant role in photoreduction of CO₂, including the more reaction sites, easier trapping of photon, and shorter charge transfer distance from interior to surface to expedite charge separation.

Anatase Mg0.05Ta0.95O1.15N0.85: a novel photocatalyst for solar hydrogen production

Anatase Mg_0.05Ta_0.95O_1.15N_0.85, exhibiting a narrow band gap for solar hydrogen, is a promising visible-light-response photocatalyst for photocatalytic or photoelectrochemical water splitting.

In situ template-free synthesis of a novel 3D p–n heteroarchitecture Ag3PO4/Ta3N5 photocatalyst with high activity and stability under visible radiation

This 3D heteroarchitecture Ag₃PO₄/Ta₃N₅ photocatalyst shows double visible-light response characteristics and sufficient hetero-interfaces between Ag₃PO₄ and Ta₃N₅.

Recent developments in heterogeneous photocatalytic water treatment using visible light-responsive photocatalysts: a review

This review summarizes the recent progress in the design, fabrication, and application of visible light-responsive photocatalysts.

Roles of TaON and Ta(3)N(5) in the visible-Fenton-like degradation of atrazine

In this study, the roles of TaON and Ta3N5 in the degradation of atrazine by the visible-Fenton-like system were examined in detail. The TaON and Ta3N5 samples prepared by the nitridation of Ta2O5 and characterized by XRD, DRS, BET and PL analyses. The results showed that the TaON sample had weaker absorption in the visible region but higher specific surface area than the Ta3N5 sample. The degradation rate of atrazine in visible-TaON-Fenton-like system was 2.64 times than that in visible-Ta3N5-Fenton-like system. Both Fe(2+) and H2O2 could be reduced by eCB (electrons in the conduction band) in TaON or Ta3N5, while atrazine could not be oxidized by hVB (holes in the valance band). OH is the active species for the degradation of atrazine in visible-TaON/Ta3N5-Fenton-like systems. Majority of OH originated from Fenton reaction. After Fe(3+) was reduced by eCB to Fe(2+), Fe(2+) reacted quickly with H2O2 to generate OH. In addition, by capturing eCB, a little of H2O2 was reduced to yield OH, which contributed a small fraction of atrazine degradation. Based on the experimental results, the roles of TaON and Ta3N5 in the visible-Fenton-like system were proposed. And the higher photocatalytic activity of TaON than Ta3N5 was suggested to be due to the higher separation efficiency of electrons and holes, which may be related to the larger specific surface area.

Photocatalytic hydrogen generation enhanced by band gap narrowing and improved charge carrier mobility in AgTaO3 by compensated co-doping

The correlation of the electronic band structure with the photocatalytic activity of AgTaO3 has been studied by simulation and experiments. Doping wide band gap oxide semiconductors usually introduces discrete mid-gap states, which extends the light absorption but has limited benefit for photocatalytic activity. Density functional theory (DFT) calculations show that compensated co-doping in AgTaO3 can overcome this problem by increasing the light absorption and simultaneously improving the charge carrier mobility. N/H and N/F co-doping can delocalize the discrete mid-gap states created by sole N doping in AgTaO3, which increases the band curvature and the electron-to-hole effective mass ratio. In particular, N/F co-doping creates a continuum of states that extend the valence band of AgTaO3. N/F co-doping thus improves the light absorption without creating the mid-gap states, maintaining the necessary redox potentials for water splitting and preventing from charge carrier trapping. The experimental results have confirmed that the N/F-codoped AgTaO3 exhibits a red-shift of the absorption edge in comparison with the undoped AgTaO3, leading to remarkable enhancement of photocatalytic activity toward hydrogen generation from water.