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Direct visualization of soft organic molecules like cellulose is extremely challenging under a high-energy electron beam. Herein, we adopt two ionization damage extenuation strategies to visualize the lattice arrangements of the β-(1→4)-d-glucan chains in carboxylated nanocellulose fibers (C-NCFs) having cellulose II crystalline phase using high-resolution transmission electron microscopy. Direct imaging of individual nanocellulose fibrils with high-resolution and least damage under high-energy electron beam is achieved by employing reduced graphene oxide, a conducting material with high electron transmittance and Ag

Direct visualization of soft organic molecules like cellulose is extremely challenging under a high-energy electron beam. Herein, we adopt two ionization damage extenuation strategies to visualize the lattice arrangements of the β-(1→4)-d-glucan chains in carboxylated nanocellulose fibers (C-NCFs) having cellulose II crystalline phase using high-resolution transmission electron microscopy. Direct imaging of individual nanocellulose fibrils with high-resolution and least damage under high-energy electron beam is achieved by employing reduced graphene oxide, a conducting material with high electron transmittance and Ag+ ions, with high electron density, eliminating the use of sample-specific, toxic staining agents, or other advanced add-on techniques. Furthermore, the imaging of cellulose lattices in a C-NCF/TiO2 nanohybrid system is accomplished in the presence of Ag+ ions in a medium revealing the mode of association of C-NCFs in the system, which validates the feasibility of the presented strategy. The methods adopted here can provide further understanding of the fine structures of carboxylated nanocellulose fibrils for studying their structure–property relationship for various applications.

The design and development of scalable, efficient photothermal evaporator systems that reduce microplastic pollution are highly desirable. Herein, a sustainable bacterial nanocellulose (BNC)-based self-floating bilayer photothermal foam (PTF

Large scale hotspot engineering is a significant approach for the development of highly efficient surface enhanced Raman scattering (SERS) platforms. Herein, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized nanocellulose fiber (T-NCF) serves as a labyrinth for developing highly sensitive and stable silver-based SERS platform enabling single molecular level SERS detection of analytes. The SERS activity of 4-methylbenzenethiol (4-MBT) in silver nanoconstructs with dissimilar size and shape (denoted as Ag/NCF-I and Ag/NCF-II systems) synthesized by varying T-NCF to Ag+ ratio, exhibited femtomolar sensitivity regardless of their structural variation. A detailed investigation of the SERS performance of both systems with 4-MBT at extremely low concentration (10−15 M) is carried out with the help of large-area Raman intensity mapping in order to evaluate the role of T-NCF in Raman signal enhancement. The analytical enhancement factors (AEFs) for Ag/NCF-I and Ag/NCF-II are calculated to be 1.4 × 1012 and 4.8 × 1011, respectively. A mechanism of local enrichment of analytes is postulated anticipating the ability of flexible nanocellulose fibers to congregate AgNPs, resulting in induced plasmonic coupling of local electromagnetic fields and high-intensity hotspot generation. The potential of T-NCF in generating hotspots can be considered as an alternative strategy to develop standards with long-term colloidal stability and scale-up production of highly sensitive AgNP based plasmonic platforms. This investigation ascertains the potential of nanocellulose fibers in the development of a robust lithography-free SERS sensing platform with single molecule level sensitivity.

An efficient solar active catalyst is in immense demand for water splitting, waste water treatment and environmental remediation applications due to the growing energy crisis. The key to improving the activity of these materials is to increase the surface area, use a dopant and reduce the charge carrier recombination. This growing concern can be addressed by graphitic carbon nitride (g-C3N4) which has excellent visible light activity. In the present work a mesoporous flower like arrangement of carbon nitride–titania nanocomposites obtained through a solvothermal method without the use of any templates at ambient temperature is reported. A detailed investigation on the formation of these mesoflowers has been studied. The properties of the nanocomposite such as efficient absorption in the visible regime and delayed recombination of charge carriers make it an apt material for solar light photocatalysis for the degradation of organic contaminants. The high surface area of 147 m2 g−1 of the mesoflowers has been utilized for heavy metal removal such as Cr(VI) with a sorption percentage of 81% within 2 minutes of contact time in simulated water samples. This report paves the way for a new class of mesoflower nanocomposites for various environmental applications.

The synthesis of shape-tuned silver (Ag) nanostructures with high plasmon characteristics has become of significant importance in in vitro diagnostic applications. Herein, we report a simple aqueous synthetic route using 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized nanocellulose fibers (T-NCFs) and trisodium citrate (TSC) that results in anisotropically grown flower-like Ag nanoconstructs (AgNFs). A detailed investigation of the concentration and sequence of the addition of reactants in the formation of these anisotropic Ag structures is presented. Our experimental results show that the mechanism underlying the formation of AgNFs is facilitated by the synergistic action of T-NCFs and TSC on the directional growth of Ag nuclei during the primary stage, which later develop into a flower-like structure by the ripening of larger particles consuming smaller Ag particles. As a result the final structure comprises flower-like morphology over which several smaller Ag particles (of size10 nm) are adhered. The aqueous AgNF colloid exhibits high stability (ζ = -69.4 mV) and long shelf-life at neutral pH (4 months) by the efficient capping action of T-NCFs. Further, an as-synthesized nanoconstructs shows excellent surface-enhanced Raman scattering activity, which enables ultrasensitive detection of p-aminothiophenol with a concentration down to 10 aM (10

We report a simple method for decorating carboxyl functionalized few-layer graphene with titania (TiO2) nanoparticles by sonication and stirring under room temperature. The nanocomposites showed a remarkable improvement in visible light driven photocatalysis. From Raman and XRD analysis the number of layers of graphene was found to be 3. The TiO2 decorated few-layer graphene (FLG) sheets were characterized by electron microscopy, Raman spectroscopy, infrared spectroscopy, XRD and UV-vis spectroscopy. Titania nanoparticles were uniformly decorated on FLG matrix. The incorporation of titania on FLG enhanced the visible light photocatalytic activity of titania, lowered the electron hole recombination and improved the electron hole mobility. The enhanced life time of the charge carriers was confirmed from the photocurrent measurements. Compared to bare TiO2 nanoparticles the FLG-TiO2 nanocomposites exhibited rapid degradation of Rhodamine B (Rhd B) under solar radiation. It was found that adsorption of dye molecules and the rate of degradation have been greatly enhanced in the FLG decorated with TiO2. The rapid degradation of Rhd B using carboxyl functionalized FLG-TiO2 within 8 min under solar radiation and 20 min under 30 W UV tube with very low concentration (0.01 wt.%) of the photocatalyst is the highlight of the present report. The mechanism of degradation and charge separation ability of the nanocomposite are also explored.