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

Effects of Heating Rate on the Nucleation, Growth, and Transformation of InOOH and In₂O₃ via Solvothermal Reactions

A solvothermal reaction is generally considered to be governed by the chemical and thermodynamic parameters. Yet, the effects of heating rate on the nucleation and growth of the target materials within solvothermal processes have been rarely reported. In this work, taking the solvothermally synthesized InOOH/In₂O₃ as the sample system we intend to illustrate that the heating rate plays an important role in the nucleation, growth, and transformation in solvothermal reactions. It is shown that with the heating rate changing from 4 to 8 °C/min, the initial nucleation temperature for ultrathin InOOH nanowires drops greatly from 160 to 120 °C. At a heating rate of 4 °C/min, the transformation from InOOH nanowires to In₂O₃ nanocubes in the one-step solvothermal system begins at 170 °C and completes at 210 °C. While at a heating rate of 8 °C/min, the transformation begins at 130 °C and completes at 180 °C. It is also found that heating rate may trigger different growth mechanisms in the solvothermal system and subsequently influence the microstructure of the products. Thus, it is anticipated that controlling the heating rate may be a potential route to tailor the morphology, microstructure, and even the properties of materials via solvothermal processes