TiO2 nanorod decorated with MoS2 nanospheres: An efficient dual-functional photocatalyst for antibiotic degradation and hydrogen production.

The design and preparation of dual-functional photocatalysts for simultaneously realizing photocatalytic wastewater purification and hydrogen energy generation pose significant challenges. This article presents the engineering of a binary heterostructured photocatalyst by combining TiO2 (nanorods) and MoS2 nanosphere using a straightforward solvothermal method and the assessment of the phase structures, morphologies, and optical properties of the resulting nanocomposites using diverse analytical techniques. The TiO2(Rod)/MoS2 composite exhibits remarkable efficacy in degrading ciprofloxacin, achieving 93% removal rate within 1 h, which is four times higher than that of bare TiO2. Moreover, the optimized TiO2(Rod)/MoS2 presents an outstanding hydrogen production rate of 7415 µmol g-1, which is ∼24 times higher than that of pristine TiO2. Under UV-visible light irradiation, the TiO2(Rod)/MoS2 heterojunction displays an exceptional photocatalytic performance in terms of both photodegradation and hydrogen production, surpassing the performance of TiO2 particle/MoS2. The study findings demonstrate that TiO2(Rod)/MoS2 nanocomposites exhibit considerably improved photocatalytic degradation and hydrogen generation activities. Based on the experimental results, a possible mechanism is proposed for the transfer and separation of charge carriers in Z-scheme heterojunctions.

"Quasi-In Situ Synthesis of Oxygen Vacancy-Enriched Strontium Iron Oxide Supported on Boron-Doped Reduced Graphene Oxide to Elevate the Photocatalytic Destruction of Tetracycline".

The efficient use of visible light is necessary to take advantage of photocatalytic processes in both indoor and outdoor circumstances. Precisely manipulating the in situ growth method of heterojunctions is an effective way to promote photogenerated charge separation. Herein, the SrFeO3@B-rGO catalyst was prepared by an in situ growth method. At a loading of 10 wt % B-rGO, the nanocomposites revealed an excellent morphology and thermal, optical, electrochemical, and mechanical properties. X-ray diffraction analysis revealed the cubic spinel structure and a space group of Pm̅3m for SrFeO3. High-resolution scanning electron microscopy and high-resolution transmission electron microscopy show the core-shell formation between SrFeO3 and B-rGO. Furthermore, density functional theory of SrFeO3 was performed to find its band structure and density of states. The SrFeO3@B-rGO nanocomposite shows the degradation rate of tetracycline (TC) reaching 92% in 75 min and the highest rate constant of 0.0211 min-1. To improve the catalytic removal rate of antibiotics, the efficiency of e- and h + separation must be improved, as well as the generation of additional radicals. Radical trapping tests and the electron paramagnetic resonance method indicated that the combination of Fe2+ and Fe3+ in SrFeO3 effectively separated e- and h+ while also promoting the development of the superoxide anion (•O2-) to accelerate TC degradation. The entire TC degradation pathway using high-performance liquid chromatography and its mechanism were discussed. As a whole, this study delineates that photocatalysis is a viable strategy for the treatment of environmental antibiotic wastewater.

Promoting Spatial Charge Transfer of ZrO2 Nanoparticles: Embedded on Layered MoS2/g-C3N4 Nanocomposites for Visible-Light-Induced Photocatalytic Removal of Tetracycline.

Photocatalytic degradation is a sustainable technique for reducing the environmental hazards created by the overuse of antibiotics in the food and pharmaceutical industries. Herein, a layer of MoS2/g-C3N4 nanocomposite is introduced to zirconium oxide (ZrO2) nanoparticles to form a "particle-embedded-layered" structure. Thus, a narrow band gap (2.8 eV) starts developing, deliberated as a core photodegradation component. Under optimization, a high photocatalytic activity of 20 mg/L TC at pH 3 with ZrO2@MoS2/g-C3N4 nanocomposite was achieved with 94.8% photocatalytic degradation in 90 min. A photocatalytic degradation rate constant of 0.0230 min-1 is determined, which is 2.3 times greater than the rate constant for bare ZrO2 NPs. The superior photocatalytic activity of ZrO2@MoS2/g-C3N4 is due to the dual charge-transfer channel between the MoS2/g-C3N4 and ZrO2 nanoparticles, which promotes the formation of photogenerated e-/h+ pairs. Charge recombination produces many free electron-hole pairs, which aid photocatalyst reactions by producing superoxide and hydroxyl radicals via electron-hole pair generation. The possible mechanistic routes for TC were investigated in-depth, as pointed out by the liquid chromatography-mass spectrometry (LC-MS) investigation. Overall, this work shows that photocatalysis is a feasible sorbent approach for environmental antibiotic wastewater treatment.

Influence of Ag nanoparticles anchored on protonated g-C3N4-Bi2MoO6 nanocomposites for effective antibiotic and organic pollutant degradation.

The development of noble metal-anchored semiconductors for photocatalytic processes is now garnering interest for potential application to toxic pollutants as well as antibiotic degradation. Herein, we report novel Ag@p-g-C3N4-Bi2MoO6 nanocomposites synthesized by facile hydrothermal and calcination methods with a size of about 50 nm, exhibiting superior photocatalytic activity for charge separation. The resulting nanocomposites were evaluated by various physiochemical techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The charge transfer photogenerated carriers were confirmed by photoluminescence spectra and electrochemical impedance spectroscopy. The anchoring of Ag nanoparticles over p-g-C3N4/Bi2MoO6 decreased the band gap energy from 2.67 to 2.48 eV, to exhibit an abnormal increase in absorption of light towards the visible light region. The degradation performance of the nanocomposites in terms of antibiotic ciprofloxacin and rhodamine B degradation efficiency was measured 85 and 99.7% respectively. The superoxide radical anion ˙O2 - played a significant role throughout the entire degradation process. Focusing on the probable mechanism based on the desirable results, the present work follows the heterostructure mechanism. Moreover, this work features the feasible applications of Ag@p-g-C3N4-Bi2MoO6 as a modified photocatalyst in the treatment of both domestic and industrial waste water.