Enhancement of visible light photocatalytic activity of Ag2O/F-TiO2 composites

Solar-powered detection of organic dyes using nitrogen-doped N-TiO2/Ag2O nanorod arrays

Organic pollutant detection has caused widespread concern regarding due to their potential environmental and human health risks. In this work, a nitrogen-doped titanium dioxide/silver oxide (N-TiO2/Ag2O) composite has been designed as a sensitive photoelectrochemical (PEC) monitoring platform of organic dyes. Sensitive determination relies on the outstanding PEC performance of N-TiO2/Ag2O. The improved PEC performance stems from the effective separation of photocarriers and the extended light response range provided by the narrowing bandgap and a p-n junction with N-TiO2/Ag2O. The N-TiO2/Ag2O electrode exhibits a photocurrent density of up to 2.2 mA/cm2, demonstrating three times increase compared with the photocurrent density observed with the pure TiO2 film. The linear detection range for rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) is 0.2 ng/mL to 10 μg/mL with an ultrasensitive detection limit of 0.2 ng/mL without bias voltage. Due to the outstanding photocurrent density and sensitive response to organic pollutants, the N-TiO2/Ag2O PEC sensor provided a promising analytical method to detect environmental organic dyes.

Biosynthesis of ZnO.Ag2O3 using aqueous extract of Haplophyllum obtusifolium: Characterization and cell toxicity activity against liver carcinoma cells

The zinc oxide‐silver oxide nanocomposite (ZnO.Ag2O3 particles) was prepared by using an aqueous plant extract of Haplophyllum obtusifolium for the first time. Powder X‐ray diffraction (PXRD), Fourier transforms spectroscopy (FTIR), field emission microscopy (FESEM), energy dispersive X‐ray analysis (EDX), and transmission electron microscopy (TEM) were applied to analyze the structure, functional groups, morphology, and purity of the prepared nanocomposite. PXRD revealed the formulation of ZnO.Ag2O3 for the particles. The investigation of functional groups has demonstrated the presence of some carbonated impurities along with absorbed water in the composition of the ZnO.Ag2O3 nanocomposite. Morphologically, particles have formed a petal‐like shape with different sizes. The EDX analysis also confirmed the composition of the prepared sample and the presence of 4.78% silver in the formula. Additionally, the TEM analysis revealed spherical and rectangular shapes with a particle size of 80.43 ± 46.73 nm. Moreover, the ZnO.Ag2O3 particles were used against cancer cells, which has shown synthesized NCs have a toxic effect against liver cancer cells in a concentration and time‐dependent manner.

Construction of Ag2O-modified g-C3N4 photocatalyst for rapid visible light degradation of ofloxacin

The design of stable and highly efficient photocatalysts had emerged as an economic and promising way for eliminating harmful pharmaceutical pollutants. In this study, a series of Ag₂O-modified g-C₃N₄ composites with different Ag₂O amounts (denoted as Ag₂O-CN_x) were fabricated via a facile reflux condensation methodology. Ofloxacin (OFL) was chosen as a model pollutant to evaluate the degradation efficiency of the photocatalytic system. The optimal photocatalytic activity was achieved with Ag₂O-CN_1.0, which reached up to 99.1% removal of OFL after 15-min reaction and the pseudo-first-order constant was 0.469 min^-1, approximately 42 times higher than that of g-C₃N₄. Considering the complexity of the actual environment, the important influential factors such as catalyst dosage, initial OFL concentration, solution pH, and natural organic matter on the OFL degradation were systematically investigated. Additionally, Ag₂O-CN_1.0 showed good stability and recyclability in multiple cycle experiments. The feasible photodegradation mechanism of OFL was proposed with radical scavenger experiments, and the degradation products were determined. Furthermore, the enhanced photocatalytic activity could be ascribed to not only the high photogenerated charge separation efficiency and the surface plasmon resonance effect of metallic Ag, but also the p-n heterojunction formed between Ag₂O and g-C₃N₄. Therefore, Ag₂O-CN_1.0 was a treatment material possessing great application prospects for eliminating OFL in wastewater.

In Situ Lithiophilic Layer from H+/Li+ Exchange on Garnet Surface for the Stable Lithium-Solid Electrolyte Interface

Garnet-type solid-state electrolytes (SSEs) show a promising application in solid-state Li batteries. Poor interfacial contact with lithium causing large interfacial impedance and dendrite penetration is a problem. Inspired by unique H⁺/Li⁺ exchange of garnet electrolyte, we used an AgNO₃ aqueous solution induced strategy to construct a lithiophilic layer in situ on the garnet surface without any specific apparatus. Experimental analysis reveals the uniform distribution of Ag nanoparticles and significantly enhanced affinity between the solid state electrolyte (SSE) and Li anode for the Li-Ag alloying. As expected, the interfacial area specific resistance (ASR) is greatly reduced to ∼4.5 Ω cm², accompanying with long-cycling stability for ∼3500 h at 0.2 mA cm^-2 and high critical current density of 0.75 mA cm^-2. With modified SSEs, quasi-solid-state batteries with a LiFePO₄ or LiNi_0.5Co_0.2Mn_0.3O₂ cathode operate well at room temperature and an all-solid-state LiFePO₄/garnet/Li battery displays good cycling stability for over 200 cycles at 60 °C.

Defect-engineered TiO2 Hollow Spiny Nanocubes for Phenol Degradation under Visible Light Irradiation

Herein, we mainly report a strategy for the facile synthesis of defect-engineered F-doped well-defined TiO2 hollow spiny nanocubes, constructed from NH4TiOF3 as precursor. The topological transformation of NH4TiOF3 mesocrystal is accompanied with fluorine anion releasing, which can be used as doping source to synthesize F-doped TiO2. Our result shows that the introduction of oxygen vacancies (Vo's) and F dopant can be further achieved by a moderate photoreduction process. The as prepared sample is beneficial to improve photocatalystic degradation and Photoelectrochemical (PEC) efficiency under visible light irradiation. And this improvement in photocatalytic and photoelectrocatalytic performance can be ascribed to the significant enhancement of visible light absorption and separation of excited charges resulted from the presence of oxygen vacancies, F- ions and hollow structure of TiO2.

Three-dimensional Ag2O/Bi5O7I p-n heterojunction photocatalyst harnessing UV-vis-NIR broad spectrum for photodegradation of organic pollutants

Ag₂O nanoparticles-loaded Bi₅O₇I microspheres forming a three dimensional Ag₂O/Bi₅O₇I p-n heterojunction photocatalyst with wide-spectrum response were synthesized in this study. The results of transmission electron microscopy observations revealed that the Ag₂O nanoparticles with the diameter of ca. 10-20nm were distributed on the surfaces of Bi₅O₇I nanosheets. The as-synthesized Ag₂O/Bi₅O₇I exhibited an excellent wide-spectrum response to wavelengths ranging from ultraviolet (UV) to near-infrared (NIR), indicating its potential for effective utilization of solar energy. Compared with pure Bi₅O₇I, the Ag₂O/Bi₅O₇I composite also demonstrated excellent photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution under visible LED light irradiation. Among samples, the 20% Ag₂O/Bi₅O₇I composite photocatalyst showed the highest photocatalytic activity for the degradation of Bisphenol A and phenol in aqueous solution. In addition, the 20% Ag₂O/Bi₅O₇I composite also exhibited a photocatalytic activity for the degradation of Bisphenol A under NIR light irradiation. The improved photocatalytic activity is attributed to the formation of a p-n heterojunction between Ag₂O and Bi₅O₇I, allowing the efficient utilization of solar energy (from UV to NIR) and high separation efficiency of photogenerated electron-hole pairs. The present work is desirable to explore a possible avenue for the full utilization of solar energy.

The design of novel visible light driven Ag/CdO as smart nanocomposite for photodegradation of different dye contaminants

In this paper, we report a novel visible light driven Ag/CdO photocatalyst, fabricated for the first time via one pot hydrothermal method and further applied for the photodegradation of two important exemplar water contaminants, Malachite green and Acid Orange 7. The microstructure, composition and optical properties of Ag/CdO nanocomposites were thoroughly investigated by various techniques. Scanning electron microscopy clearly shows that Ag NPs were strongly embedded between the CdO nanoparticles. Among the series of synthesized Ag/CdO nanocomposites, (5%) Ag/CdO nanocomposite possesses enhanced photocatalytic activity. This result was attributed to the synergistic effect between Ag and CdO, and mainly Ag NPs can act as an electron trap site, which could reduce the recombination of the electron-hole and induce the visible light absorption. The active species trapping experiments implicate OH and O₂^- radicals as the respective primary and secondary reactive species responsible for oxidative photodegradation of organic pollutants. On the basis of the results, a possible photocatalytic mechanism has also been proposed.

Combination of a graphene SERS substrate and magnetic solid phase micro-extraction used for the rapid detection of trace illegal additives

Surface enhanced Raman scattering (SERS) is an ultra-sensitive spectroscopy technique, which can provide rich structural information for a great number of molecules, while solid phase micro-extraction (SPME) is an efficient method for sample pretreatment in analytical chemistry, particularly in a micro-system.

Recent advances in nanomaterials for water protection and monitoring

Nanomaterials (NMs) for adsorption, catalysis, separation, and disinfection are scrutinized. NMs-based sensor technologies and environmental transformations of NMs are highlighted.

In situ growth of Ag/Ag2O nanoparticles on g-C3N4 by a natural carbon nanodot-assisted green method for synergistic photocatalytic activity

Novel visible-light-driven Ag/Ag₂O@g-C₃N₄ hybrid materials were synthesized successfully via a green, facile hydrothermal treatment approach by reducing AgNO₃ with carbon nanodots for the first time.

Ultrafast piezo-photocatalytic degradation of organic pollutions by Ag2O/tetrapod-ZnO nanostructures under ultrasonic/UV exposure

Ultrafast degradation of organic pollutions has been realized by the piezo-photocatalytic activity of Ag₂O/tetrapod-ZnO nanostructures under ultrasonic/UV irradiation.

Constructing novel Ag nanoparticles anchored on MnO2 nanowires as an efficient visible light driven photocatalyst

We report the first construction of novel Ag nanoparticles anchored on MnO₂ nanowires as an efficient visible light driven photocatalyst.