Visible-Light-Active BiOI/TiO2 Heterojunction Photocatalysts for Remediation of Crude Oil-Contaminated Water

In this study, BiOI-sensitized TiO2 (BiOI/TiO2) nanocomposites with different levels of BiOI deposited via sequential ionic layer adsorption and reaction (SILAR) have been explored for the degradation of methyl orange, 4-chlorophenol (4-CP), and crude oil in water under visible (>400 nm) irradiation with excellent degradation performance. The reaction progress for methyl orange and 4-chlorophenol was monitored by a UV-vis spectrophotometer, and the degradation of the crude oil hydrocarbons was determined by GC-MS. The BiOI/TiO2 heterojunction improves separation of photogenerated charges, which enhances the degradation efficiency. Evaluation of the visible-light photocatalytic performance of the synthesized catalysts against methyl orange degradation confirmed that four SILAR cycles are the optimal deposition condition for the best degradation efficiency. The efficiency was further confirmed by degrading 4-CP and crude oil, achieving 38.30 and 85.62% degradation, respectively, compared with 0.0% (4-CP) and 70.56% (crude oil) achieved by TiO2. The efficiency of TiO2 in degrading crude oil was mainly due to adsorption along with photolysis. This study provides a simple and cost-effective alternative to traditional remediation methods requiring high energy consumption for remediation of crude oil-polluted water and refinery wastewater using visible-light photocatalysis along with adsorption.

Intelligent Nanomaterials for Wearable and Stretchable Strain Sensor Applications: The Science behind Diverse Mechanisms, Fabrication Methods, and Real-Time Healthcare

It has become a scientific obligation to unveil the underlying mechanisms and the fabrication methods behind wearable/stretchable strain sensors based on intelligent nanomaterials in order to explore their possible potential in the field of biomedical and healthcare applications. This report is based on an extensive literature survey of fabrication of stretchable strain sensors (SSS) based on nanomaterials in the fields of healthcare, sports, and entertainment. Although the evolution of wearable strain sensors (WSS) is rapidly progressing, it is still at a prototype phase and various challenges need to be addressed in the future in special regard to their fabrication protocols. The biocalamity of COVID-19 has brought a drastic change in humans' lifestyles and has negatively affected nations in all capacities. Social distancing has become a mandatory rule to practice in common places where humans interact with each other as a basic need. As social distancing cannot be ruled out as a measure to stop the spread of COVID-19 virus, wearable sensors could play a significant role in technologically impacting people's consciousness. This review article meticulously describes the role of wearable and strain sensors in achieving such objectives.

UV-Improved Removal of Chloride Ions from Strongly Acidic Wastewater Using Bi2O3: Efficiency Enhancement and Mechanisms

Strongly acidic wastewater generated from nonferrous metal smelting industries can be recycled as sulfuric acid after the contaminants have been removed, and among which, Cl^- is rather difficult to remove. Although previous studies showed that Cl^- can be removed from acidic Zn electrolyte by Bi₂O₃, this method still suffers from low efficiency when being employed for strongly acidic wastewater recycling. Otherwise, very high Bi₂O₃ dosage and H₂SO₄ concentration are required, leading to the need for improvement. In this study, UV irradiation was employed to improve the removal, and it was found that Cl^- removal efficiency was substantially enhanced from 63.9 to 98.3%, the optimum Bi₂O₃/Cl^- mole ratio was lowered from 1.5:1 to 0.5:1, and to achieve the maximum removal efficiency, the required H₂SO₄ concentration was lowered from 70 to 40 g/L. The mechanisms were also elaborated. First, Bi₂O₃ dissolves under the function of UV and H⁺, and the produced Bi³⁺ combines with H₂O and Cl^- to form BiOCl. Then, Bi₂O₃/BiOCl transforms into BiOCl(h⁺)/Bi₂O₃(e^-) under UV irradiation, and the generated h⁺ oxidizes Cl^- to Cl^•. Finally, Cl^• reacts with Bi₂O₃/e^- to produce BiOCl. This study offered a theoretical foundation for the improvement of Cl^- removal from strongly acidic wastewater.

Synthesis, electron transfer and photocatalytic activity of TiO2 nanotubes sensitized by meso-tetra(4-carboxyphenyl)porphyrin under visible-light irradiation

Porphyrin plays a crucial role in the process of photocatalysis, porphyrin compounds are naturally suitable antennas for solar energy collection and promising direct solar energy-to-chemical conversion equipment.

Enhanced photocatalytic activity of α-Fe2O3/Bi2WO6 heterostructured nanofibers prepared by electrospinning technique

One-dimensional α-Fe₂O₃/Bi₂WO₆ heterostructured nanofibers with the diameter of about 300–500 nm were successfully prepared by using a simple and straightforward protocol combining an electrospinning technique with a sintering process.

Review of one-dimensional and two-dimensional nanostructured materials for hydrogen generation

Hydrogen is an attractive alternative to fossil fuels in terms of environmental and other advantages.