Visible light-driven photocatalyst: An iron(III) coordination compound in Rhodamine B degradation

N-Doped TiO2 Coupled with Manganese-Substituted Phosphomolybdic Acid Composites As Efficient Photocatalysis-Fenton Catalysts for the Degradation of Rhodamine B

The effectiveness of photocatalytic and Fenton reactions in the synergistic treatment of water pollution problems has become indisputable. In this paper, nitrogen-doped TiO₂ was selected as the catalyst for the photocatalytic reaction and manganese-substituted phosphomolybdic acid was used as the Fenton reagent, the two of which were combined together by acid impregnation to construct a binary photocatalysis-Fenton composite catalyst. The degradation experiments of the composite catalyst on RhB indicated that under UV-vis irradiation, the composite catalyst could degrade RhB almost completely within 8 min, and the degradation rate was 19.7 times higher than that of N-TiO₂, exhibiting a superior degradation ability. Simultaneously, a series of characterization methods were employed to analyze the structure, morphology, and optical properties of the catalysts. The results demonstrated that the nitrogen doping not only expanded the photo response range of TiO₂ but reduced the work function of TiO₂, which facilitated the transfer of electrons to the loaded Mn-HPMo side and further promoted the electron-hole separation efficiency. In addition, the introduction of Mn-HPMo provided three pathways for the activation of hydrogen peroxide, which enhanced the degradation activity. This study provides novel insights into the construction of binary and efficient catalysts with multiple hydroxyl radical generation pathways.

A green approach for the preparation of ZnO@C nanocomposite using agave americana plant extract with enhanced photodegradation

The present study demonstrates the crucial role of agave americana extract in enhancing the optical properties of zinc oxide (ZnO) through thermal treatment method. Various analytical and surface science techniques have been used to identify the morphology, crystalline structure, chemical composition, and optical properties, including scanning electron microscopy, x-ray diffraction, high resolution transmission electron microscopy (HRTEM), x-ray spectroscopy (EDS) and UV-visible spectroscopy techniques. The physical studies revealed the transformation of ZnO nanorods into nanosheets upon addition of an optimized amount of agave americana extract, which induced large amount of amorphous carbon deposited onto ZnO nanostructures as confirmed by HRTEM analysis. The use of increasing amount of americana extract has significantly reduced the average crystallite size of ZnO nanostructures. The resultant hybrid system of C@ZnO has produced a significant effect on the ultraviolet light-assisted photodegradation of malachite green (MG) dye. The photocatalyst dose was fixed at 10 mg for each study whereas the amount of agave americana extract and MG dye concentration are varied. The functionality of hybrid system was greatly enhanced when the amount of agave americana extract increased while dye concentration kept at lower level. Ultimately, almost 100% degradation efficiency was achieved via the prepared hybrid material, revealing combined contribution from synergy, stabilization of ZnO due to excess of carbon together with the high charge separation rate. The obtained results suggest that the driving role of agave americana extract for surface modification of photocatalyst can be considered for other nanostructured photocatalysts.

Synthesis, Characterization, and Photocatalytic Activity of Mixed-Ligand Cerium(III) and Bismuth(III) Complexes

Two ternary complexes (Ce(sal)3(phen)2) (1) and (Bi(sal)3(phen)2) (2) with salicylic acid (sal) and 1,10-phenanthroline (phen) have been synthesized and characterized by analytical techniques such as UV-visible spectroscopy, FT-IR spectroscopy, PXRD, and SEM. The UV-visible study indicated the shifting of peak positions of metal complexes compared with the individual ligands whereas FT-IR analysis demonstrated that the metals were successfully coordinated with different functional groups of the ligands. The photocatalytic properties of prepared complexes were evaluated against Congo red dye as a model pollutant under ultraviolet and sunlight irradiation. The degradation efficiency of complex (2) was greater than that of complex (1). The results indicated that the investigated complexes can be employed as potential candidates for photocatalytic breakdown of synthetic dyes and can be safely recommended for environmental remediation.