Dual modification of TiO2 nanorod arrays with SiW11Co and Ag nanoparticles for enhanced photocatalytic activity under simulated sunlight

Design of TiO2/Ag3BiO3 n-n heterojunction for enhanced degradation of tetracycline hydrochloride under visible-light irradiation

Pharmaceutical residual contaminants in aquatic ecosystems have caused severe risks to human health. Affordable, eco-friendly and effective photocatalysts to deal with these pollutants has become a hot topic in the scientific community. In this research, Ag₃BiO₃ nanoparticles were embedded on TiO₂ to form n-n heterojunction through a facile hydrothermal method. According to scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), brunauer emmett teller (BET), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) tests, the successful construction of TiO₂/Ag₃BiO₃ heterojunction is proved. TiO₂/Ag₃BiO₃ heterojunctions were employed as photocatalysts to remove tetracycline hydrochloride (TCH) under visible light irradiation in aqueous solution. Optimum TCH photodegradation efficiency was observed for TiO₂/Ag₃BiO₃ (10%), 15.4 times superior to that of TiO₂. The enhanced TCH photodegradation efficiency of TiO₂/Ag₃BiO₃ results from improved light absorption capacity and the reduction of recombination of photogenerated charge carriers via generation of n-n heterojunctions. The mechanism of increasing the photodegradation efficiency of TCH was determined by employing reactive species quenching experiments. TiO₂/Ag₃BiO₃ (10%) also exhibited an acceptable stability.

In situ sulfidation of porous sponge-like CuO/SiW11Co into Cu2S/SiW11Co as stabilized and efficient counter electrode for quantum dot-sensitized solar cells

Quantum dot-sensitized solar cells (QDSSCs), which are cost-effective, facilely prepared and environmentally friendly, are regarded as a promising third-generation photovoltaic technology, although the conversion efficiency of QDSSCs is still far lower than the theoretical efficiency (44%). Furthermore, the traditional Cu₂S/brass counter electrode (CE) is susceptible to continuous corrosion from the polysulfide electrolyte, reducing the stability and electrocatalytic activity of the CE, thereby affecting cell performance. To enhance the stability of the Cu₂S CE and make full use of its excellent catalytic properties, we used eco-friendly polyoxometalates (K₆SiW₁₁O₃₉Co(ii) (H₂O), SiW₁₁Co) and porous sponge-like CuO as precursors to prepare a novel SiW₁₁Co-doped high-efficiency Cu₂S/SiW₁₁Co CE on FTO by adopting the method of in situ sulfidation in the electrolyte. Electrochemical analysis revealed that the novel Cu₂S/2%-SiW₁₁Co (Cu₂S-2) CE exhibits extremely high stability and electrocatalytic performance compared with other electrodes. Meanwhile, adding an appropriate amount of SiW₁₁Co can inhibit charge recombination and improve cell performance. The CdS/CdSe co-sensitized QDSSCs assembled with the novel Cu₂S-2 CE obtained a power conversion efficiency (PCE) of 5.94%, which was 20% more efficient than QDSSCs based on Cu₂S/brass CE (4.96%). The method reported here puts forth a new direction for the preparation of efficient Cu₂S counter electrodes.

Five Keggin-based compounds modified by bis- and mono-[1,3,4]triazole ligands: characterization, and selective photocatalytic and electrochemical properties

By using three kinds of triazole-containing ligands under hydrothermal conditions, five kinds of 0D to 3D POM-based compounds were successfully synthesized. These compounds have good photocatalytic selectivity and electrocatalytic activity.