Qingqing Zhu,Xiaojuan Zhang,Li Li,Chao Cheng,Jun Zheng,Youmin Guo,Chunchang Wang
This study focuses on enhancing the piezoelectric photocatalytic activity of BiFeO 3 through rare earth ion doping. By doping rare earth ions (La, Sm, Ce), the crystal structure, optical properties, and piezoelectric properties of BiFeO 3 are modified. The results show that the doping alters the rhombic structure, reduces the band gap, and enhances light absorption. A synergistic system combining ultraviolet − visible spectral irradiation and a high − frequency ultrasonic field was used. By monitoring the decomposition kinetics of Rhodamine B (RhB) and the generation pathways of free radicals, the multi-field coupling catalytic efficiency of piezoelectric semiconductor materials was systematically quantified. The doping significantly improves the degradation rate, with Bi 0.8 Sm 0.2 FeO 3 showing the best performance. The roles of different radicals in the degradation process are investigated, and the catalyst shows good stability and sustainability after multiple cycles.
An oriented hierarchical ZnO flower-rod arrays (FRs) were prepared on indium doped tin oxide (ITO) glass using a facile solution-based method assisted with ZnO seed layer. And the as-prepared ZnO FRs/ITO was used as a convenient photocatalytic device that recycled without centrifugation. The results show that ZnO FRs are wurtzite phase with single crystalline grown along the [0 0 1] direction. The photoluminescence (PL) spectra illustrate that there are more oxygen vacancies on the surface of ZnO FRs compared with ZnO nanoparticles (NPs). The electrochemical methods using Rhodamine B (RhB) as electrolyte are also performed to study on the photodegradation mechanism where RhB is acted as photocatalytic substrate. For ZnO FRs, the higher photoinduced currents under UV irradiation and current density prove that the recombination of electron–hole pairs is restrained with oxygen vacancies, and the lower charge transfer resistance suggest that the charges could move quickly through ZnO oriented structures. Therefore, the photocatalytic activity is enhanced by ZnO FRs compared with ZnO NPs, and RhB degradation efficiency of ZnO FRs photocatalysts is nearly 100% by UV irradiation for 1.5 h.
Yinhua Jiang,Fan Li,Yan Liu,Yuanzhi Hong,Peipei Liu,Liang Ni
An interlayer structure hybrid photocatalyst of TiO 2 hollow sphere/g-C 3 N 4 (TOCN) has been successfully constructed via a facile impregnation process. The photocatalytic activity was evaluated by degrading Rhodamine B under visible irradiation. TOCN-2 with 33 wt.% g-C 3 N 4 had much higher photocatalytic efficiency (98.09%) than pure g-C 3 N 4 (18.62%) and TiO 2 hollow sphere (16.37%). Significantly, TOCN-2 showed much superior photocatalytic performance than TiO 2 nanoparticle/g-C 3 N 4 composite (53.16%), indicating the hollow morphology of TiO 2 also played a crucial role for RhB degradation. In TOCN system, both the morphology effect of TiO 2 and the synergistic effects between TiO 2 and g-C 3 N 4 resulted in significantly enhancing photocatalytic performance.
Lei Shi,Jinling Gou,Lin Liang,Fangxiao Wang,Jianmin Sun
A g-C3N4/Ag2WO4 composite photocatalyst was synthesized via a simple co-precipitation method at room temperature and was thoroughly characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The characterization results indicated that upon depositing Ag2WO4 onto the surface of g-C3N4 its morphology changed from primary rod-like particles to globular nanoparticles and its phase changed from α-type to β-type Ag2WO4. When the composite was used as the catalyst in the photodegradation of Rhodamine B, 40%-g-C3N4/Ag2WO4 exhibited the highest photocatalytic activity with its rate constant was about 10.8 times larger than that of pure g-C3N4 and 3.12 times larger than that of bare Ag2WO4. The enhanced photocatalytic activity can be attributed to the complementary potentials of the conduction bands and valence bands of g-C3N4 and Ag2WO4, which could not only realize the effective separation of photoinduced electron and hole pairs, but also retained the catalysts high stability and photocatalytic performance even after five recycles. Furthermore, a possible photocatalytic mechanism for the degradation of RhB over the g-C3N4/Ag2WO4 composite was proposed according to the results of active species quenching experiments.
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