Topochemical-like bandgap regulation engineering: A bismuth thiooxide nanocatalyst for breast cancer phototherapy

The physical property tuning of nanomaterials is of great importance in energy, medicine, environment, catalysis, and other fields. Topochemical synthesis of nanomaterials can achieve precise control of material properties. Here, we synthesized a kind of element-doped bismuth-based nanomaterial (BOS) by topochemical-like synthesis and used it for the phototherapy of tumors. In this study, we employed bismuth fluoride nanoflowers as a template and fabricated element-doped bismuth oxide nanoflowers by reduction conditions. The product is consistent with the precursor in crystal structure and nanomorphology, realizing topochemical-like synthesis under mild conditions. BOS can generate reactive oxygen species, consume glutathione, and perform photothermal conversion under 730 nm light irradiation. In vitro and in vivo studies demonstrate that BOS could suppress tumor growth by inducing apoptosis and ferroptosis through phototherapy. Therefore, this study offers a general regulation method for tuning the physical properties of nanomaterials by using a topochemical-like synthesis strategy.

Novel PWO/ ZnO heterostructured nanocomposites: Synthesis, characterization, and photocatalytic performance

Photocatalytic degradation is becoming an increasingly attractive method for addressing environmental remediation challenges. In this work, the novel pure PWO/ZnO and doped PWO: Er/ZnO: Ag heterostructure nanocomposites with premier photocatalytic efficiency were synthesized via a simple co-precipitation method followed by a solvothermal procedure. X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX), and ultraviolet-visible (UV-Vis) absorbance measurements techniques were employed to characterize the structural and optical properties. HRTEM images prove the possibility of intimate contact formation at the pure and doped PWO/ZnO heterostructure nanocomposite interfaces. The photocatalytic performance of the PWO/ZnO heterostructure nanocomposites in the degradation of the methylene blue (MB) and methyl orange (MO) dyes under UVA light was evaluated. The photocatalysts' ability in the mineralization of organic pollutants was confirmed by the TOC test. BET and zeta potential analyses were used to study the dye adsorption mechanisms. Additionally, adsorption isotherms and kinetics have been investigated to describe the adsorption of MB and MO into the samples. The degradation rates of MB with PWO/ZnO and PWO: Er/ZnO: Ag heterostructure nanocomposites were 4.7 and 6.6 times higher than those of PWO and PWO: Er nanoparticles. This rate for MO degradation is 5.2 and 3.5 times higher than that of pure PWO and PWO: Er nanoparticles, respectively. This study outlines an easy method to develop innovative, highly effective heterostructure nanocomposites capable of converting UVA light into photocatalytic performance.

Hydrogen-bonded silicene nanosheets of engineered bandgap and selective degradability for photodynamic therapy

Silicon, a highly biocompatible and ubiquitous chemical element in living systems, exhibits great potentials in biomedical applications. However, the silicon-based nanomaterials such as silica and porous silicon have been largely limited to only serving as carriers for delivery systems, due to the lack of intrinsic functionalities of silicon. This work presents the facile construction of a two-dimensional (2D) hydrogen-bonded silicene (H-silicene) nanosystem which is highlighted with tunable bandgap and selective degradability for tumor-specific photodynamic therapy facilely by surface covalent modification of hydrogen atoms. Briefly, the H-silicene nanosheet material is selectively degradable in normal neutral tissues but rather stable in the mildly acidic tumor microenvironment (TME) for achieving efficient photodynamic therapy (PDT). Such a 2D hydrogen-bonded silicene nanosystem featuring the tunable bandgap and tumor-selective degradability provides a new paradigm for the application of multi-functional two-dimensional silicon-based biomaterials towards the diagnosis and treatments of cancer and other diseases.

Predicting the trend and utility of different photocatalysts for degradation of pharmaceutically active compounds: A special emphasis on photocatalytic materials, modifications, and performance comparison

The rapid rise in the healthcare sector has led to an increase in pharmaceutically active compounds (PhACs) in different aqueous bodies. The toxicity of the PhACs and their ability to persist after conventional treatment processes have escalated research in the field of photocatalytic treatment. Although different photocatalysts have been successful in degrading PhACs, their inherent drawbacks have severely limited their application on a large scale. A substantial amount of research has been aimed at overcoming the high cost of the photocatalytic material, low quantum yield, the formation of toxic end products, etc. Hence, to further research in this field, researchers must have a fair idea of the current trends in the application of different photocatalysts. In this article, the trends in the use of various photocatalysts for the removal of different PhACs have been circumscribed. The performance of different groups of photocatalysts to degrade PhACs from synthetic and real wastewater has been addressed. The drawbacks and advantages of these materials have been compared, and their future in the field of PhACs removal has been predicted using S-curve analysis. Zinc and titanium-based photocatalysts were efficient under UV irradiation, while bismuth and graphene-based materials exhibited exemplary performance in visible light. However, iron-based compounds were found to have the most promising future, which may be because of their magnetic properties, easy availability, low bandgap, etc. Different modification techniques, such as morphology modification, doping, heterojunction formation, etc., have also been discussed. This study may help researchers to clarify the current research status in the field of photocatalytic treatment of PhACs and provide valuable information for future research.

Polymeric graphitic carbon nitride (g-C3N4)-based semiconducting nanostructured materials: Synthesis methods, properties and photocatalytic applications

In recent years, various facile and low-cost methods have been developed for the synthesis of advanced nanostructured photocatalytic materials. These catalysts are required to mitigate the energy crisis, environmental deterioration, including water and air pollution. Among the various semiconductors explored, recently novel classes of polymeric graphitic carbon nitride (g-C₃N₄)-based heterogeneous photocatalysts have established much greater importance because of their unique physiochemical properties, large surface area, low price, and long service life, ease of synthesis, product scalability, controllable band gap properties, low toxicity, and high photocatalytic activity. The present comprehensive review focuses on recent achievements in a number of facile chemical synthesis methods for semiconducting polymeric carbon nitrides and their heterogeneous nanohybrids with various dopants, nanostructured metals, metal oxides, and nanocarbons, as well as the parameters influencing their physiochemical properties and photocatalytic efficiency, which are discussed with reference to various catalytic applications such as air (NO_x) purification, wastewater treatment, hydrogen generation, CO₂ reduction, and chemical transformation. The mechanisms for the superior photocatalytic activity of polymeric g-C₃N₄-based heterogeneous photocatalysts are also discussed. Finally, the challenges, prospects, and future directions for photocatalytic polymeric g-C₃N₄-based semiconducting materials are described.

Controllable Vapor Growth of Large-Area Aligned CdS x Se1-x Nanowires for Visible Range Integratable Photodetectors

The controllable growth of large area band gap engineered-semiconductor nanowires (NWs) with precise orientation and position is of immense significance in the development of integrated optoelectronic devices. In this study, we have achieved large area in-plane-aligned CdS _x Se_1-x nanowires via chemical vapor deposition method. The orientation and position of the alloyed CdS _x Se_1-x NWs could be controlled well by the graphoepitaxial effect and the patterns of Au catalyst. Microstructure characterizations of these as-grown samples reveal that the aligned CdS _x Se_1-x NWs possess smooth surface and uniform diameter. The aligned CdS _x Se_1-x NWs have strong photoluminescence and high-quality optical waveguide emission covering almost the entire visible wavelength range. Furthermore, photodetectors were constructed based on individual alloyed CdS _x Se_1-x NWs. These devices exhibit high performance and fast response speed with photoresponsivity ~ 670 A W^-1 and photoresponse time ~ 76 ms. Present work provides a straightforward way to realize in-plane aligned bandgap engineering in semiconductor NWs for the development of large area NW arrays, which exhibit promising applications in future optoelectronic integrated circuits.