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In situ synthesis of visible-light-driven Z-scheme AgI/Bi2WO6 heterojunction photocatalysts with enhanced photocatalytic activity
摘要： In this work, an efficient visible-light-response AgI/Bi2WO6 heterojunction was successfully prepared via in situ precipitation of AgI nanoparticles on the aligned nanosheets of three-dimensional Bi2WO6 hierarchical microspheres for the first time. Studies suggested that the AgI/Bi2WO6 heterojunction exhibited excellent photocatalytic activity for tetracycline (TC) degradation compared to pure Bi2WO6 and AgI under visible light irradiation. Doping 20 wt% AgI resulted in the optimal TC photodegradation rate, which was 5.4 and 3.3 times higher than pure Bi2WO6 and AgI, respectively. The high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) verified that Ag nanoparticles generated on AgI/Bi2WO6 heterojunction surface in photocatalytic degradation process, which was beneficial for promoting the rapid combination of electrons on the conduction band of Bi2WO6 with the holes on the valence band of AgI and the separation and transfer of photogenerated electron-hole pairs. Accordingly, the nontraditional transport pathway of photogenerated electrons and holes based on the Z-scheme system that consisted of Bi2WO6, AgI, and Ag was confirmed. Based on the systematic experimental evidence, the possible enhanced photocatalytic mechanism was proposed.
关键词： Z-scheme,Photocatalysis,Heterojunction,AgI/Bi2WO6,Tetracycline
更新于2025-09-23 15:23:52
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Ag3PO4 modified phosphorus and sulphur co-doped graphitic carbon nitride as a direct Z-scheme photocatalyst for 2, 4-dimethyl phenol degradation
摘要： Very recently, hybrid photocatalysts are gaining importance due to their unique and enhanced photocatalytic activity. In precedent study, we have successfully prepared Ag3PO4 (AP) and P and S co-doped g-C3N4 (PSGCN) based AP/PSGCN photocatalyst via facile deposition-precipitation method. The P and S co-doped g-C3N4 was prepared via thermal poly-condensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. The photocatalysts were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The thickness of AP/PSGCN was less than 9.0 nm. The zeta potential and Tyndall effect experiments validated the formation of well dispersed suspension of AP/PSGCN in water. The co-doping resulted in lowering of optical band gap of g-C3N4. The Tyndall effect experiments ascertained the formation of well dispersed suspension of AP/PSGCN. The photoluminescence and electrochemical impedance analysis confirmed reduction in recombination of photogenerated electron and hole pairs. The photodegradation of 2,4-dimethyl phenol (DMP) followed pseudo first order kinetics. The enhanced photocatalysis was due to direct Z-scheme mechanism. Hydroxyl and superoxide radicals were the two main reactive species during DMP degradation. The COD, HPLC and LC-MS investigations ascertained mineralization of DMP. AP/PSGCN displayed high stability and recycle efficiency significant for ten catalytic cycles.
关键词： DMP,Ag3PO4,P and S Co-doped g-C3N4,Nanocomposite,Z-scheme photocatalysis
更新于2025-09-23 15:22:29
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Direct Z-scheme photocatalytic removal of ammonia via the narrow band gap MoS2/N-doped graphene hybrid catalyst upon near-infrared irradiation
摘要： Near-infrared (NIR) irradiation accounts for approximately 54.3% of the solar spectrum. Therefore, MoS2 and N-doped graphene (NG) were utilised to fabricate a direct Z-scheme NIR-response photocatalytic system (MoS2/NG). The photocatalytic tests showed that MoS2/NG Z-scheme photocatalytic system can result in a 99.6% degradation ratio of ammonia under NIR irradiation, whereas the removal ratio of ammonia was only 64.0% using MoS2 as the photocatalyst under similar conditions. The catalytic e?ciency is still over 90.7% even if the MoS2/NG catalyst was used for ?ve runs, indicating that it is extremely stable. The kinetic research indicated the ?1. The average apparent rate constant kapp for ammonia degradation into N2 was at approximately 0.251 h enhanced photocatalytic activity of MoS2/NG was attributed to the more positive valence band level of the Z-scheme system.
关键词： MoS2/N-doped graphene,Near-infrared irradiation,Degradation ammonia,Narrow band gap,Z-scheme photocatalysis
更新于2025-09-12 10:27:22
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Study on the visible-light photocatalytic performance of Ag3PO4/Cu2O composite
摘要： Ag3PO4/Cu2O composites were prepared by a facile wet chemical method. The specimens were examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV–Vis diffuse reflectance spectroscopy. The specimens exhibited an excellent photocatalytic activity on the degradation of RhB than pure Ag3PO4 and Cu2O. Furthermore, the photocatalyst specimen was found to exhibit higher efficiency in hydrogen conversion. It was found that a 30? wt% Ag3PO4-loaded specimen showed an excellent hydrogen generation performance. The excellent photocatalytic activity was ascribed to the separation of e–h pairs via the Z-scheme method composed of Ag, Ag3PO4 and Cu2O. This study demonstrated the potential approach to the photocatalytic splitting water to release hydrogen as well as the environmental purification of organic pollutants under visible-light irradiation.
关键词： Cuprous oxide,Z-scheme,Photocatalysis,Water splitting
更新于2025-09-10 09:29:36