The photocatalytic water splitting technique is a promising alternative to produce hydrogen using a facile and proficient method. In the current Review, recent progress made in photocatalytic hydrogen evolution reaction (HER) using 2D nanomaterials (NMs) and composite heterostructures is described. The strong in-plane chemical bonds along with weak van der Waals interaction make these materials lucrative for surface-related applications. State-of-the-art protocols designed for the synthesis of 2D NMs is discussed in detail. The Review illustrates density functional theory (DFT)-based studies against the new set of 2D NMs, which also highlights the importance of structural defects and doping in the electronic structure. Additionally, the Review describes the influence of electronic, structural, and surface manipulation strategies. These impact the electronic structures, intrinsic conductivity, and finally output toward HER. Moreover, this Review also provides a fresh perspective on the prospects and challenges existing behind the application and fabrication strategies.

The recent advent of biodegradable materials has offered huge opportunity to transform healthcare technologies by enabling sensors that degrade naturally after use. The implantable electronic systems made from such materials eliminate the need for extraction or reoperation, minimize chronic inflammatory responses, and hence offer attractive propositions for future biomedical technology. The eco-friendly sensor systems developed from degradable materials could also help mitigate some of the major environmental issues by reducing the volume of electronic or medical waste produced and, in turn, the carbon footprint. With this background, herein we present a comprehensive overview of the structural and functional biodegradable materials that have been used for various biodegradable or bioresorbable electronic devices. The discussion focuses on the dissolution rates and degradation mechanisms of materials such as natural and synthetic polymers, organic or inorganic semiconductors, and hydrolyzable metals. The recent trend and examples of biodegradable or bioresorbable materials-based sensors for body monitoring, diagnostic, and medical therapeutic applications are also presented. Lastly, key technological challenges are discussed for clinical application of biodegradable sensors, particularly for implantable devices with wireless data and power transfer. Promising perspectives for the advancement of future generation of biodegradable sensor systems are also presented.

No abstract

Growth in production of manufactured goods and the use of nanomaterials in consumer products has mounted in the past few decades. Nanotoxicology or toxicity assessment of these engineered products is required to understand possible adverse effects and their fate inside the human body. The present review is a one stop assessment intended to be a state of the art understanding on nanotoxicity. It provides a summation of the various kinds of cell death and also discusses the different types of toxicities along with their studies. The review discusses the physiological impact imparted on cells (reactive oxygen species generation and the resultant oxidative stress, inflammation, and other nonoxidant pathways). Moreover, it discusses the different physicochemical properties of nanomaterials (size, morphology, surface charge, and coating) governing the cytotoxicity properties. It also details the major pathways of nanomaterial uptake in cells and their outcome. Additionally, it also discusses the possible methods for human exposure to nanomaterials (skin, respiratory tract, gastrointestinal tract, blood brain barrier, liver, and spleen). Furthermore, an entire new section is contributed in discussion of all possible types of assays (cytotoxicity, cell proliferation, and genotoxicity assays). A summarized discussion of the recent advances on in vitro, in silico, and in vivo studies of nanomaterials (metal, metal oxides, carbon nanotubes, graphene, and other novel materials) is made. The review also provides a brief account of the safety guidelines for handling nanomaterials. Finally, the uses of engineered nanomaterials in commercial products are discussed in detail.

Surface contamination by microbes is a major public health concern. A damp environment is one of potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO2) can effectively curb this growing threat. Metal-doped titania in anatase phase has been proven as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu)-doped TiO2 (Cu-TiO2) was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO2 was carried out via sol-gel technique. Cu-TiO2 further calcined at various temperatures (in the range of 500–700 °C) to evaluate the thermal stability of TiO2 anatase phase. The physico-chemical properties of the samples were characterized through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV–visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO2 was maintained well, up to 650 °C, by the Cu dopant. UV–vis results suggested that the visible light absorption property of Cu-TiO2 was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasize the introduction of Cu+ and Cu2+ ions by replacing Ti4+ ions in the TiO2 lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9999%) was attained in 30 min of visible light irradiation by Cu-TiO2.

No abstract

No abstract

Environmental remediation employing semiconducting materials offer a greener solution for pollution control. Herein, we report the development of high surface area porous architecture of C3N4 nanosheets by a simple aqueous spray drying process. g-C3N4 nanosheets obtained by the thermal decomposition of urea-thiourea mixture are spray granulated to microspheres using 2 wt% poly vinyl alcohol (PVA) as binder. The post granulation thermal oxidation treatment resulted in in situ doping of carbon leading to improved photophysical properties compared to pristine g-C3N4. The C3N4 granules with surface area values of 150 m2/g rendered repetitive adsorption of tetracycline antibiotic (∼75% in 60 min) and the extended absorption in the visible region facilitated complete photocatalytic degradation upon sunlight irradiation (>95% in 90 min). The delocalized π bonds generated after carbon doping and the macro-meso porous architecture created by the granulation process aided high adsorption capacity (70 mg/g). The photoregenerable, bifunctional materials herein obtained can thus be employed for the adsorption and subsequent degradation of harmful organic pollutants without any secondary remediation processes.