We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

The energy used for regulating building temperatures accounts for 14% of the primary energy consumed in the U.S. One-quarter of this energy is leaked through ineffcient glass windows in cold weather. The development of transparent composites could potentially provide affordable window materials with enhanced energy effciency. Transparent wood as a promising material has presented desirable performances in thermal and light management. In this work, the performance of transparent wood is optimized toward an energy effcient window material that possesses the following attributes: 1) high optical transmittance (≈91%), comparable to that of glass; 2) high clarity with low haze (≈15%); 3) high toughness (3.03 MJ m−3) that is 3 orders of magnitude higher than standard glass (0.003 MJ m−3); 4) low thermal conductivity (0.19 W m−1 K−1) that is more than 5 times lower than that of glass. Additionally, the transparent wood is a sustainable material, with low carbon emissions and scaling capabilities due to its compatibility with industryadopted rotary cutting methods. The scalable, high clarity, transparent wood demonstrated in current work can potentially be employed as energy effcient and sustainable windows for signifcant environmental and economic benefts.

https://www.fpl.fs.fed.us/documnts/pdf2020/fpl_2020_mi001.pdf

A Clear, Strong, and Thermally Insulated Transparent Wood for Energy Efficient Windows

The complex structure of wood, one of the most abundant biomaterials on Earth, has been optimized over 270 million years of tree evolution. This optimization has led to the highly efficient water and nutrient transport, mechanical stability and durability of wood. The unique material structure and pronounced anisotropy of wood endows it with an array of remarkable properties, yielding opportunities for the design of functional materials. In this Review, we provide a materials and structural perspective on how wood can be redesigned via structural engineering, chemical and/or thermal modification to alter its mechanical, fluidic, ionic, optical and thermal properties. These modifications enable a diverse range of applications, including the development of high-performance structural materials, energy storage and conversion, environmental remediation, nanoionics, nanofluidics, and light and thermal management. We also highlight advanced characterization and computational-simulation approaches for understanding the structure–property–function relationships of natural and modified wood, as well as informing bio-inspired synthetic designs. In addition, we provide our perspective on the future directions of wood research and the challenges and opportunities for industrialization. The porous hierarchical structure and anisotropy of wood make it a strong candidate for the design of materials with various functions, including load bearing, multiscale mass transport, and optical and thermal management. In this Review, the composition, structure, characterization methods, modification strategies, properties and applications of natural and modified wood are discussed.

Structure-property-function relationships of natural and engineered wood

Potential applications of deep eutectic solvents in nanotechnology

The light-harvesting and recycle of powder photocatalyst in suspended system are bottlenecks for high-efficient solar photocatalysis. Floating photocatalyst are highly sought-after and good candidates for practical environmental application due to the satisfaction with above requirements simultaneously. Over the past decades, floating TiO2-based photocatalysts have attracted much attention, which makes great progress and it is significant to review the recent advances. This review highlights the rational design and fabrication strategy for floating photocatalyst immobilized on various lightweight substrates (e.g. perlite, vermiculite, glass microbead, polymer, cork, expanded graphite) or self-floating photocatalyst. The special characteristics and deep understanding of photocatalytic mechanism for floating photocatalyst are summarized and discussed thoroughly. Moreover, the future research and challenge will focus on designing and optimizing the high-efficient broadband response floating photocatalyst to improve solar energy utilization. From an application viewpoint, floating photocatalyst have real practical applications in natural environment and are worthy of great attention.

Recent advances in floating TiO2-based photocatalysts for environmental application

Natural wood is functionalized using the index matching poly(methyl methacrylate) (PMMA) and luminescent γ-Fe2O3@YVO4:Eu3+ nanoparticles to form a novel type of luminescent and transparent wood composite. First, the delignified wood template was obtained from natural wood through a lignin removal process, which can be used as a support for transparent polymer and phosphor nanoparticles. Then, the functionalization occurs in the lumen of wood, which benefits from PMMA that fills the cell lumen and enhances cellulose nanofiber interaction, leading to wood composites with excellent thermal properties, dimensional stability, and mechanical properties. More importantly, this wood composite displays a high optical transmittance in a broad wavelength range between 350 and 800 nm, magnetic responsiveness, and brightly colored photoluminescence under UV excitation at 254 nm. The unique properties and green nature of the luminescent wood composite have great potential in applications including green LED lighting eq...

Luminescent and Transparent Wood Composites Fabricated by Poly(methyl methacrylate) and γ-Fe2O3@YVO4:Eu3+ Nanoparticle Impregnation

Wood is one of the key renewable resources due to its excellent structure and physical properties. Functionalized wood and wood-based materials not only possess important engineering applications but also great potential in some new technology fields, such as electronics, optics, and energy. Endowing these functional wood-based materials with magnetic properties has an important significance for exploring lightweight building materials or electronic devices. In this study, we report the fabrication of a transparent magnetic wood (TMW) based on filling the index-matching methyl methacrylate and magnetic Fe3O4 nanoparticles into the delignified wood template. The presence of the polymer and Fe3O4 nanoparticles within the wood structure is monitored by scanning electron microscopy, energy-dispersive X-ray analysis, and Fourier transformation infrared spectroscopy. The resulting TMW possesses moderate transparency and magnetic properties combining with outstanding mechanical performance. Moreover, the influence of the concentration of Fe3O4 nanoparticles on the final optical, magnetic, and mechanical properties of TMW is also discussed. This work provides a potential strategy to develop wood-based materials for magneto-optical application.

Transparent magnetic wood composites based on immobilizing Fe3O4 nanoparticles into a delignified wood template

A two-step method containing low-temperature hydrothermal synthesis with TiO 2 precursor solution and subsequent modification with fluoroalkyl silane on wooden substrates was investigated. Scanning electron microscopy (Scanning electron microscope) images showed that the TiO 2 -treated wood substrate was covered with uniform TiO 2 particles, which generated a roughness on the wood surface favoring the formation of the superhydrophobic surface, and the decoration of (heptadecafluoro-1,1,2,2-tetradecyl)trimethoxysilane on TiO 2 -based wood surface acted as a crucial role in improving the repellency toward water. The superhydrophobic wood surface with the water contact angle (WCA) of 152.9°, maintained superhydrophobic property with the WCA larger than 150° after immerse in 0.1 M hydrochloric acid solution for one week, irradiating under UV light for 24 h, or boiling at 150 °C for 10 h. The prepared wood surface showed multi-functions including super repellency toward water, anti-acid, and high-temperature–humidity-resistant. On the basis of the results, the functional coating on the wood surface provided an enlarged field of the wood works, such as historic structure protection.

A robust, anti-acid, and high-temperature–humidity-resistant superhydrophobic surface of wood based on a modified TiO2 film by fluoroalkyl silane

A robust superhydrophobic antibacterial Ag–TiO2 composite film immobilized on wood substrate for photodegradation of phenol under visible-light illumination

A facile route was adopted to synthesize heterostructured WO3/TiO2 photocatalysts from wood fibers through a two-steps hydrothermal method and a calcination process. The prepared WO3/TiO2-wood fibers were used as photocatalysts under UV irradiation for photodegradation of rhodamine B, methylene blue and methyl orange. In calcination process, the wood fibers acted as carbon substrates to prepare the WO3/TiO2 photocatalysts with high surface area and unique morphology. Thus, the significant enhanced photodegradation efficiency of the organic pollutants with the WO3/TiO2-wood fibers under UV irradiation was obtained. The photodegradation rates are measured which confirms the highest performance of the WO3/TiO2-wood fibers after calcination in comparison to the TiO2-wood fibers after calcination and the pure WO3/TiO2 after calcination. Moreover, the photodegradation efficiency of the WO3/TiO2-wood fibers after calcination under visible light is high. Our results demonstrated that the WO3/TiO2-wood fibers after calcination are a promising candidate for wastewater treatment in practical application.

/pdf/preparation-of-heterostructured-wo-3-tio-2-catalysts-from-3tvua1n3wr.pdf

Xianxu Zhan

Papers

Luminescent and Transparent Wood Composites Fabricated by Poly(methyl methacrylate) and γ-Fe2O3@YVO4:Eu3+ Nanoparticle Impregnation

Transparent magnetic wood composites based on immobilizing Fe3O4 nanoparticles into a delignified wood template

A robust, anti-acid, and high-temperature–humidity-resistant superhydrophobic surface of wood based on a modified TiO2 film by fluoroalkyl silane

A robust superhydrophobic antibacterial Ag–TiO2 composite film immobilized on wood substrate for photodegradation of phenol under visible-light illumination

Preparation of heterostructured WO 3/TiO 2 catalysts from wood fibers and its versatile photodegradation abilities