Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.

Nanocelluloses: A New Family of Nature-Based Materials

The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...

http://pubs.acs.org/doi/pdfplus/10.1021/acs.chemrev.5b00482

Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

In recent years, tremendous research effort has been aimed at increasing the energy density of supercapacitors without sacrificing high power capability so that they reach the levels achieved in batteries and at lowering fabrication costs For this purpose, two important problems have to be solved: first, it is critical to develop ways to design high performance electrode materials for supercapacitors; second, it is necessary to achieve controllably assembled supercapacitor types (such as symmetric capacitors including double-layer and pseudo-capacitors, asymmetric capacitors, and Li-ion capacitors) The explosive growth of research in this field makes this review timely Recent progress in the research and development of high performance electrode materials and high-energy supercapacitors is summarized Several key issues for improving the energy densities of supercapacitors and some mutual relationships among various effecting parameters are reviewed, and challenges and perspectives in this exciting field are also discussed This provides fundamental insight into supercapacitors and offers an important guideline for future design of advanced next-generation supercapacitors for industrial and consumer applications

Recent Advances in Design and Fabrication of Electrochemical Supercapacitors with High Energy Densities

Over the past few decades, the design and development of advanced electrocatalysts for efficient energy conversion technologies have been subjects of extensive study. With the discovery of graphene, two-dimensional (2D) nanomaterials have emerged as some of the most promising candidates for heterogeneous electrocatalysts due to their unique physical, chemical, and electronic properties. Here, we review 2D-nanomaterial-based electrocatalysts for selected electrocatalytic processes. We first discuss the unique advances in 2D electrocatalysts based on different compositions and functions followed by specific design principles. Following this overview, we discuss various 2D electrocatalysts for electrocatalytic processes involved in the water cycle, carbon cycle, and nitrogen cycle from their fundamental conception to their functional application. We place a significant emphasis on different engineering strategies for 2D nanomaterials and the influence these strategies have on intrinsic material performance, ...

Emerging Two-Dimensional Nanomaterials for Electrocatalysis

https://cyberleninka.org/article/n/1316165.pdf

Nanocellulose in biomedicine: Current status and future prospect

Bacterial cellulose (BC) produced by some microorganisms has been widely accepted as a multifunctional nano-biomaterial. It is composed of linear glucan molecules attached with hydrogen bonds, which appears similar to plant cellulose. However, when compared with other conventional natural or synthesized counterparts, BC performs better in areas such as biomedicine, functional devices, water treatment, nanofillers, etc. for its distinct superior chemical purity, crystallinity, biocompatibility, and ultrafine network architecture. When BC is incorporated in a material or used as a scaffold, novel features result that are related to BC’s intrinsic characteristics mentioned above. This review mainly summarizes the recent developments of the functional products fabricated with BC. Besides, the controllable cultivation conditions should also be discussed for expecting to make a breakthrough in its productivity. We highlight the literatures mainly in last 5 years, exerting ourselves to provide the state-of-the-art opinions in areas wherever are focused on for BC researching.

Recent advances in bacterial cellulose

Bacterial cellulose (BC) nanofiber-supported polyaniline (PANI) nanocomposites have been synthesized via in situ polymerization of aniline onto BC nanofibers scalfold. Optimized preparation conditi...

Bacterial Cellulose Nanofiber-Supported Polyaniline Nanocomposites with Flake-Shaped Morphology as Supercapacitor Electrodes

Well-designed nanostructures of a ternary nanocomposite, graphene/Fe2O3/polyaniline, are fabricated via a two-step approach. Graphene oxide is reduced by Fe2+ and well-dispersed by loading α-Fe2O3 nanoparticles (20–70 nm in size). A thin film of polyaniline is in situ polymerized on the graphene/Fe2O3 surfaces for the fabrication of its ternary composite. Among the composites obtained at different ratios of graphene/Fe2O3 to polyaniline, the ternary graphene/Fe2O3/polyaniline with a ratio of 2 : 1 exhibits a high specific capacitance of 638 F g−1 in 1 M KOH at a scan rate of 1 mV s−1 and experiences only a negligible decay of 8% after 5000 cycles. It also shows a higher energy density at high power density than other ternary or binary composites of the three components, respectively. The extraordinary electrochemical performance of the composite arises from the well-designed structural advantages of the ternary nanocomposite, and the good combination and synergistic effects among the three components. Graphene sheets, as the conducting frameworks for sustaining polyaniline and Fe2O3, can separate and disperse well in the composite due to the existence of Fe2O3. On the other hand, the thin film of polyaniline on the surface of graphene/Fe2O3 not only enhances the surface area, but also restricts the dissolution, aggregation and volume changes of Fe2O3 during charge–discharge cycling. Additionally, the existence of Fe2O3 is helpful to increase the rate stability of the ternary composite. The ternary composites with synergistic effects can take advantage of both Faradaic and non-Faradaic processes for capacity-charge storage with excellent electrochemical properties.

Dongping Sun

Papers

Recent advances in bacterial cellulose

Bacterial Cellulose Nanofiber-Supported Polyaniline Nanocomposites with Flake-Shaped Morphology as Supercapacitor Electrodes

Nanostructured ternary composites of graphene/Fe2O3/polyaniline for high-performance supercapacitors

Amorphous Fe 2 O 3 nanoshells coated on carbonized bacterial cellulose nanofibers as a flexible anode for high-performance lithium ion batteries

Graphene nanoplate-Pt composite as a high performance electrocatalyst for direct methanol fuel cells