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

Improved Electron Transfer between TiO₂ and FTO Interface by N‑Doped Anatase TiO₂ Nanowires and Its Applications in Quantum Dot-Sensitized Solar Cells

The growth of anatase TiO₂ nanowires (NWs) on fluorine doped tin oxide (FTO) substrates through hydrothermal reaction has attracted wide attention and research, especially in the case of the solar cells. Actually, the built-in electric field at the anatase TiO₂ NWs/FTO interface leads to the photoexcited holes transfer to FTO conductive substrates because the Fermi energy of anatase TiO₂ NWs film is higher than that of FTO substrates. Yet efficient transport of photoexcited electron to the FTO conductive substrates is desirable. Hence, the built-in electric field at the pure TiO₂ NWs/FTO interface has prevented anatase TiO₂ NWs-based solar cells from achieving a higher photoelectric performance. In this work, we elaborately design and construct the N-doped anatase TiO₂ NWs/FTO interface with the desirable orientations from FTO toward N-doped anatase TiO₂ NWs, which favors the photoexcited electron transfer to the FTO conductive substrates. The surface photovoltage (SPV) and Kelvin probe measurements demostrate that the N-doped anatase TiO₂ NWs/FTO interface favors the photoexcited electron transfer to the FTO conductive substrates due to the fact that the orientation of the built-in electric field at the N-doped TiO₂ NWs/FTO interface is from FTO toward TiO₂. The photoexcited charge transfer dynamics of CdS QD-sensitized TiO₂ NWs and N-doped TiO₂ NWs electrodes was investigated using the transient photovoltage (TPV) and transient photocurrent (TPC) technique. Benefiting from the desirable interface electric field, CdS-based quantum dot-sensitized solar cells (QDSCs) with the optimal N doping amount exhibit a remarkable solar energy conversion efficiency of 2.75% under 1 sun illumination, which is 1.46 times enhancement as compared to the undoped reference solar cells. The results reveal that the N-doped anatase TiO₂ NWs electrodes have promising applications in solar cells

Effect of Photogenerated Charge Transfer on the Photocatalysis in High-Performance Hybrid Pt–Co:ZnO Nanostructure Photocatalyst

Hybrid Pt–Co:ZnO nanostructure photocatalysts were prepared via a facile two-step synthetic strategy. SPS and TPV investigations demonstrate the existence of the synergetic effect between Pt and Co dopants. Such synergetic effect could make use of visible photons as well as facilitates the separation of photogenerated charges to prevent recombination, effectively prolongating the charges lifetime to participate photocatalytic reaction. The synergetic effect exist in Pt–Co:ZnO inducing as high as 7.7-fold in photovoltaic response and 10-fold in the photo–activity for hybrids compared to Co:ZnO