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

The use of deuteration in medicinal chemistry has exploded in the past years, and the FDA has recently approved the first deuterium-labeled drug. Precision deuteration goes beyond the pure and simple amelioration of the pharmacokinetic parameters of a drug and might provide an opportunity when facing problems in terms of metabolism-mediated toxicity, drug interactions, and low bioactivation. The use of deuterium is even broader, offering the opportunity to lower the degree of epimerization, reduce the dose of coadministered boosters, and discover compounds where deuterium is the basis for the mechanism of action. Nevertheless, designing, synthesizing, and developing a successful deuterated drug is far from straightforward, and the translation from concept to practice is often unpredictable. This Perspective provides an overview of the recent developments of deuteration, with a focus on deuterated clinical candidates, and highlights both opportunities and challenges of this strategy.

Applications of Deuterium in Medicinal Chemistry

Thick Electrode Batteries: Principles, Opportunities, and Challenges

It remains a great challenge to develop high-efficient, low-cost and robustly stable bifunctional oxygen electrocatalysts for rechargeable metal-air batteries. Herein, we report a promising electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The electrocatalysts are composed of nanostructured FeNi alloy nanoparticles inlaid on N-doped carbon nanotubes (CNTs)-tangled porous carbon fibers (FeNi/N-CPCF). Benefiting from its hierarchically porous structures with bamboo-like CNTs grafted, and strong synergetic coupling between FeNi alloys and N-doped carbon species, the as-prepared FeNi/N-CPCF-950 demonstrates a half-wave potential of 0.867 V for ORR and a low operating potential of 1.585 V at 10 mA cm−2 for OER in 0.1 M KOH, outperforming commercial Pt/C and RuO2. Moreover, such bifunctioal catalyst endows the homemade zinc-air batteries with a high energy efficiency of 61.5%, small charge-discharge voltage gap of 0.764 V, and outstanding cycling performance (640 h, 960 cycles) at 10 mA cm−2 under ambient conditions.

FeNi alloys encapsulated in N-doped CNTs-tangled porous carbon fibers as highly efficient and durable bifunctional oxygen electrocatalyst for rechargeable zinc-air battery

As one of the most promising alternatives for future energy systems, the rechargeable Zn–air battery (ZAB) has attracted extensive attention due to its extraordinarily high theoretical specific energy density. However, several obstacles restrict its practical application. One challenge is the sluggish kinetics of oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) in the discharging and charging processes of ZABs. In addition, when using unifunctional ORR or OER electrocatalysts as air electrodes, like noble metal catalysts (Pt/C or Ru/IrO2), there are the disadvantages of high cost and poor stability. Therefore, rational design of non-noble metal bifunctional ORR/OER electrocatalysts with high activity and stability is essential for the development of ZABs. In this review, we discuss the latest developments of non-noble metal bifunctional ORR/OER electrocatalysts for ZABs. Firstly, the related reaction mechanisms of ORR and OER are introduced. Then, the latest developments of bifunctional ORR/OER materials for ZABs are discussed in detail from three aspects: (i) MOF-based catalysts, including pristine MOFs and their derivatives; (ii) metal-free-based carbon catalysts, including heteroatom-doped carbon and defective carbon; (iii) metal-based catalysts, including metal–nitrogen–carbon materials (such as metals/alloys, single-atom) and metal compound materials. Finally, some challenges and outlooks for the optimal design of bifunctional air electrodes for rechargeable ZABs with high activity and ultra-long lifetime are put forward.

Bifunctional electrocatalysts for Zn–air batteries: recent developments and future perspectives

Porous carbon electrodes have emerged as important cathode materials for metal-air battery systems. However, most approaches for fabricating porous carbon electrodes from biomass are highly energy inefficient as they require the breaking down of the biomass and its subsequent reconstitution into powder-like carbon. Here, enzymes are explored to effectively hydrolyze the partial cellulose in bulk raw wood to form a large number of nanopores, which helps to maximally expose the inner parts of the raw wood to sufficiently dope nitrogen onto the carbon skeletons during the subsequent pyrolysis process. The resulting carbons exhibit excellent catalytic activity with respect to the oxygen reduction and oxygen evolution reactions. As-fabricated cellulose-digested, carbonized wood plates are mechanically strong, have high conductivity, and contain a crosslinked network and natural ion-transport channels and can be employed directly as metal-free electrodes without carbon paper, polymer binders, or carbon black. When used as metal-free cathodes in zinc-air batteries, they result in a specific capacity of 801 mA h g-1 and an energy density of 955 W h kg-1 with the long-term stability of the batteries being as high as 110 h. This work paves the way for the ready conversion of abundant biomass into high-value engineering products for energy-related applications.

Hierarchically Porous Carbon Plates Derived from Wood as Bifunctional ORR/OER Electrodes.

Hierarchically Porous Carbon Plates Derived from Wood as Bifunctional ORR/OER Electrodes

Deuterium labeling is of great value in organic synthesis and the pharmaceutical industry. However, the state-of-the-art C-H/C-D exchange using noble metal catalysts or strong bases/acids suffers from poor functional group tolerances, poor selectivity and lack of scope for generating molecular complexity. Herein, we demonstrate the deuteration of halides using heavy water as the deuteration reagent and porous CdSe nanosheets as the catalyst. The deuteration mechanism involves the generation of highly active carbon and deuterium radicals via photoinduced electron transfer from CdSe to the substrates, followed by tandem radicals coupling process, which is mechanistically distinct from the traditional methods involving deuterium cations or anions. Our deuteration strategy shows better selectivity and functional group tolerances than current C-H/C-D exchange methods. Extending the synthetic scope, deuterated boronic acids, halides, alkynes, and aldehydes can be used as synthons in Suzuki coupling, Click reaction, C-H bond insertion reaction etc. for the synthesis of complex deuterated molecules.

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Controllable deuteration of halogenated compounds by photocatalytic D 2 O splitting

The invention belongs to the technical field of battery catalysts, and discloses a nitrogen-doped 3D porous carbon material, and a preparation method and application thereof. The method comprises thefollowing steps: (1) pretreating a biomass material in a cellulase solution to obtain a pretreated biomass material, wherein the biomass material is eucalyptus and/or poplar; (2) carbonizing the pretreated biomass material to obtain a porous carbon material; (3) mixing porous carbon and nitrogen-containing compound in water, drying and carbonizing to obtain a nitrogen-doped three-dimensional porous carbon material; the carbonization temperature being 800 ~ 1000 DEG C. The nitrogen-doped three-dimensional porous carbon material of the invention has a high specific surface area, a multi-stage pore structure, good oxygen reduction and oxygen precipitation activities and high catalytic activity. The method of the invention is simple, and the raw material used is a biomass material, which is cheap, easy to obtain and renewable. The nitrogen-doped three-dimensional porous carbon material can be applied to the field of catalysis.

A nitrogen-doped 3D porous carbon material and a preparation method and application thereof

A nitrogen-doped 3D porous carbon material, a preparation method therefor and use thereof. The preparation method comprises: (1) pre-treating a biomass material in a cellulase solution to obtain a pre-treated biomass material, the biomass material being eucalyptus wood and/or poplar wood; (2) carbonizing the pre-treated biomass material to obtain a porous carbon material; and (3) mixing the porous carbon with a nitrogen-containing compound in water, and performing drying and carbonization to obtain a nitrogen-doped three-dimensional porous carbon material. The temperature of carbonization is 800-1000 °C.

Xinwen Peng

Papers

Hierarchically Porous Carbon Plates Derived from Wood as Bifunctional ORR/OER Electrodes.

Hierarchically Porous Carbon Plates Derived from Wood as Bifunctional ORR/OER Electrodes

Controllable deuteration of halogenated compounds by photocatalytic D 2 O splitting

A nitrogen-doped 3D porous carbon material and a preparation method and application thereof

Nitrogen-doped 3d porous carbon material, preparation method therefor and use thereof