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

Investigation on synthesis of ternary g-C3N4/ZnO-W/M nanocomposites integrated heterojunction II as efficient photocatalyst for environmental applications

The rapid industrialization of the world is disparagingly manipulating our environment and natural ecosystem. The researchers are taking keen interest to invent novel material as photocatalyst for non-degradable organic pollutants. Solar energy-driven practices employing semiconductors are a novel approach towards wastewater remediation. Here in, we successfully synthesized a vigorous photocatalysts comprising of g-C₃N₄ and doped ZnO-W/M (M = Co, Ce, Yb, Sm) by co-precipitation followed by metals doping via calcination approach. The structural, morphological, and photocatalytic applications for organic pollutants of synthesized heterostructure nanocomposites were examined by XRD, FTIR, SEM, EDX and UV visible spectrophotometer. Diffraction peaks attributed to both g-C₃N₄ and ZnO-W were detected in the XRD spectra. The FTIR spectra also inveterate the formation of g-C₃N₄/ZnO-W/M composites. The SEM images reveal an agglomerated morphology and EDS analysis also confirmed close contact between g-C₃N₄, ZnO-W and doped metals. The abridged energy band gap of g-C₃N₄/ZnO-W/M (M = Ce, Yb, Sm, Co) nanocomposites calculated via Tauc plot are 2.68, 2.88, 3.24 and 3.29 eV respectively. Narrowing of bandgap is considered an imperative triumph for the degradation of industrial effluents. The photocatalytic activity was performed against four different dyes and follows the trend Ce > Yb > Sm > Co. The recyclability tests were carried out for different dyes and no substantial catalytic activity loss was observed even after the fourth experimental run, which proves that reported ternary heterojunctions exhibit high mechanical stability and reusability.The species trapping experiment exposed that generated h⁺ are the principal active specie for dye photodegradation reactions. This work disseminates a novel photocatalyst for the removal of synthetic dyes.

Influence of Calcination Temperature on Photocatalyst Performances of Floral Bi2O3/TiO2 Composite

Heterojunction photocatalytic materials show excellent performance in degrading toxic pollutants. This study investigates the influence of calcination temperature on the performances of floral Bi2O3/TiO2 composite photocatalyst crystal, which was prepared with glycerol, bismuth nitrate, and titanium tetrachloride as the major raw materials via the solvothermal method. XRD, SEM/TEM, BET, Uv-vis, and XPS were employed to analyze the crystal structure, morphology, specific surface area, band gap, and surface chemical structure of the calcined temperature catalysts. The calcination temperature influence on the catalytic performance of composite photocatalysis was tested with rhodamine B (RhB) as the degradation object. The results revealed the high catalytic activity and higher photocatalytic performance of the Bi2O3/TiO2 catalyst. The degradation efficiency of the Bi2O3/TiO2 catalyst to RhB was 97%, 100%, and 91% at 400 °C, 450 °C, and 500 °C calcination temperatures, respectively, in which the peak degradation activity appeared at 450 °C. The characterization results show that the appropriate calcination temperature promoted the crystallization of the Bi2O3/TiO2 catalyst, increased its specific surface area and the active sites of catalytic reaction, and improved the separation efficiency of electrons and holes.