Facile construction of multifunctional xNiCo2O4/BiVO4 heterojunction with accelerated charge transfer for efficient photocatalytic treatment of Cr (VI), MB and TC under visible light.

The release of industrial effluents, comprising of organic dyes, antibiotics, and heavy metals poses substantial environmental and ecological threats. Among the different approaches, the utilization of heterogeneous photocatalysis based on semiconducting metal oxides is of paramount important to removal of organic ( MB dye and TC antibiotic) and inorganic pollutants ( Cr (VI) ) in wastewater. In this work, a new approach for creating type-II heterojunction photocatalysts named xNiCo2O4/BiVO4 or BNC is suggested. The as-prepared samples were thoroughly examined by means of several sophisticated analytical tools to investigate their physicochemical properties. These composites were utilized in the decomposition of MB dye, TC drug and the reduction of Cr (VI) under visible light irradiation. According to the findings, the creation of type-II heterojunction at BiVO4-NiCo2O4 interface greatly improved charge transportation while successfully preventing electron-hole recombination. Among the various composites studied, BNC-2 demonstrated an enhanced photocatalytic activity towards degradation of MB and TC, which were found to be 91 % over a period of 150 min and 95 % within only 60 min, respectively. Moreover, the photocatalytic reduction of Cr (VI) was accomplished 96 % within just 25 min. Additionally, it is discovered that BNC-2 displayed promising photostability and recyclability with a retention of >90 % after five consecutive cycles. The enhanced photocatalytic activity of BNC-2 is evidently attributed to the expedited separation and transfer of charges, as proven by photocurrent measurement, photoluminescence and electrochemical impedance spectroscopy analyses. Hence, the current amalgamation of NiCo2O4 and BiVO4 heterojunction composite has paved novel paths towards photocatalytic removal of organic as well as inorganic contaminants.

Interface-engineered Z-scheme of BiVO4/g-C3N4 photoanode for boosted photoelectrochemical water splitting and organic contaminant elimination under solar light.

Although n-type bismuth vanadate (BiVO4) is regarded as an attractive solar-light-active photoanode, its short carrier-diffusion length, sluggish oxidation kinetics, low electronic conductivity, and high recombination rate are the major intrinsic shortcomings that limit its practical application. To this end, the rational design of a solar-light-active, metal-free BiVO4-based Z-scheme heterojunction photoanode is of great significance for achieving effective charge-separation features and maximum light utilization as well as boosting redox activity for efficient environmental treatment and photoelectrochemical water splitting. Herein, we propose a facile approach for the decoration of metal-free graphitic carbon nitride (g-C3N4) nanosheets on BiVO4 to form a Z-scheme BiVO4/g-C3N4 photoanode with boosted photoelectrochemical (PEC) water splitting and rapid photoelectrocatalytic degradation of methyl orange (MO) dye under simulated solar light. The successful preparation of the Z-scheme BiVO4/g-C3N4 photoanode was confirmed by comprehensive structural, morphological, and optical analyses. Compared with the moderate photocurrent density of bare BiVO4 (0.39 mA cm-2), the Z-scheme BiVO4/g-C3N4 photoanode yields a notable photocurrent density of 1.14 mA cm-2 at 1.23 V vs. RHE (≈3-fold higher) with the promising long-term stability of 5 h without any significant photo-corrosion. Moreover, the PEC dye-degradation studies revealed that the Z-scheme BiVO4/g-C3N4 photoanode successfully degraded MO (≈90%) in 75 min, signifying a 30% improvement over bare BiVO4. This research paves the way for rational interface engineering of solar-light-active BiVO4-based noble-metal-free Z-schemes for eco-friendly PEC water splitting and water remediation.

Advanced metal and carbon nanostructures for medical, drug delivery and bio-imaging applications.

Nanoparticles (NPs) offer great promise for biomedical, environmental, and clinical applications due to their several unique properties as compared to their bulk counterparts. In this review article, we overview various types of metal NPs and magnetic nanoparticles (MNPs) in monolithic form as well as embedded into polymer matrices for specific drug delivery and bio-imaging fields. The second part of this review covers important carbon nanostructures that have gained tremendous attention recently in such medical applications due to their ease of fabrication, excellent biocompatibility, and biodegradability at both cellular and molecular levels for phototherapy, radio-therapeutics, gene-delivery, and biotherapeutics. Furthermore, various applications and challenges involved in the use of NPs as biomaterials are also discussed following the future perspectives of the use of NPs in biomedicine. This review aims to contribute to the applications of different NPs in medicine and healthcare that may open up new avenues to encourage wider research opportunities across various disciplines.

Dual Functional Ta-Doped Electrospun TiO2 Nanofibers with Enhanced Photocatalysis and SERS Detection for Organic Compounds.

There is a growing interest in multifunctional nanomaterials for the detection as well as degradation of organic contaminants in the water. In this work, we report on the development of dual functional TiO2 nanofibers (TNF) with different tantalum (Ta) doping (1-10 mol %) by a simple electrospinning technique. As-prepared TNF show mesoporous dominant structure, which are favorable for photocatalytic activity due to the presence of catalytic spots. Ta doping decreases the crystalline size within TiO2 matrix because of the incorporation of Ta5+ ions and restricts the phase transformation from anatase to rutile. Ta doping slightly enhances the visible light absorption because of the Ti3+ defects sites created upon Ta5+ doping. The effect of Ta doping within TiO2 matrix was systematically studied for the degradation of methylene blue (MB) dye under ultraviolet (UV) and solar light irradiation. The 5% Ta-doped TNF were found to be optimal and showed 5.1 and 2.2 times higher photocatalytic activity as compared to TNF under UV and solar light irradiation, respectively. The effect of Ta doping for the detection of MB molecules was also studied by surface enhanced Raman scattering (SERS). It was observed that 5% Ta-doped TNF exhibit higher photocatalytic activity and enhanced SERS signals of adsorbed MB molecules as compared to the TNF. The enhanced photocatalytic and SERS activities can be explained as combined effects of enhanced visible light absorption, lower crystalline size, and slightly higher surface area. The observed results show that Ta doping induces new energy levels below the conduction band of TiO2 because of Ti3+ defects, which inhibit the photogenerated charge recombination acting as electron traps and promote charge transfer mechanism acting as an intermediate state for TiO2 to MB molecule electron transfer, and are mainly responsible for the enhanced photocatalytic and SERS activities, respectively.