Emerging approaches of utilizing trees to produce advanced structural and functional materials.

The global number of trees is approximately 3 trillion, covering 31% of the land area. Trees are considered a cheap, abundant, renewable, and environmentally friendly feedstock for producing advanced structural and functional materials toward a widespread application in sustainable energy and environment. In this highlight, we reveal the structure and composition of wood, leaves, and tree extracts, and then highlight the strategies to control their hierarchical structures and properties.

Complete Degradation of Polyolefin Plastic Wastes to High-Value Products.

Plastic wastes continuously accumulate, causing critical environmental issues. It is urgent to develop efficient strategies to convert them to valuable products. Very recently, two novel approaches for plastic recycling were reported by Huber et al.

Gradient Functional Layer Anode for Carbonate-Superstructured Solid Fuel Cells with Ethane Fuel.

Carbonate-superstructured solid fuel cells (CSSFCs) are an emerging type of fuel cells with high flexibility of fuels. However, using ethane fuel for solid fuel cells is a great challenge due to serious degradation of their anodes. Herein, this critical issue is solved by creating a novel gradient functional layer anode for CSSFCs.

Facile and Scalable Synthesis of Metal- and Nitrogen-Doped Carbon Nanotubes for Efficient Electrochemical CO Reduction.

Metal- and nitrogen-doped carbon (M-N-C) is a promising material to catalyze electrochemical CO reduction reaction (CORR). However, most M-N-C catalysts in the literature require complicated synthesis procedures and produce small quantities per batch, limiting the commercialization potential. In this work, we developed a simple and scalable synthesis method to convert metal-impurity-containing commercial carbon nanotubes (CNTs) and nitrogen-containing organic precursors into M-N-C via one-step moderate-temperature (650 °C) pyrolysis without any other treatment nor the need to add metal precursors.

Thermo-photo catalytic anode process for carbonate-superstructured solid fuel cells.

Converting hydrocarbons and greenhouse gases (i.e., carbon dioxide, CO) directly into electricity through fuel cells at intermediate temperatures (450 to 550 °C) remains a significant challenge, primarily due to the sluggish activation of C-H and C=O bonds.

Critical Role of In-Situ-Generated Eutectic Carbonates in Superstructured Solid Fuel Cells.

As a distinct type of fuel cell, a carbonate-superstructured solid fuel cell (CSSFC), which possesses excellent performance and easy fabrication as well as low cost, was recently invented by our group. Herein, we demonstrated the critical role of the in-situ-generated eutectic carbonate phase in CSSFC. Namely, the in-situ generation of eutectic LiCO/NaCO system increased the oxygen ionic conductivity of CeSmO solid electrolyte by 20 times (from 3.

Modification Strategies for Development of 2D Material-Based Electrocatalysts for Alcohol Oxidation Reaction.

2D materials, such as graphene, MXenes (metal carbides and nitrides), graphdiyne (GDY), layered double hydroxides, and black phosphorus, are widely used as electrocatalyst supports for alcohol oxidation reactions (AORs) owing to their large surface area and unique 2D charge transport channels. Furthermore, the development of highly efficient electrocatalysts for AORs via tuning the structure of 2D support materials has recently become a hot area. This article provides a critical review on modification strategies to develop 2D material-based electrocatalysts for AOR.

Direct Observation of Twin van der Waals Molecular Chains.

The van der Waals (vdW) assemblies are the most common structures of materials. However, direct mapping of intermolecular electron clouds of a vdW assembly has never been obtained, even though the intramolecular electron clouds were visualized by atomic-resolution techniques. In this report, we unprecedentedly mapped the intermolecular electron cloud of the assemblies of ethanol molecules via ethyl groups with high-resolution atomic force microscopy and scanning tunneling microscopy at 5 K, leading to the first visualization of vdW molecular chains, in which ethanol molecules assemble into twin vdW molecular chains in a reverse parallel configuration on the Ag(111) plane.

Chemical recycling of plastic wastes with alkaline earth metal oxides: A review.

Plastics have been widely used in daily life and industries due to their low cost and high durability, leading to huge production of plastics and tens of millions of plastic wastes every year. Chemical recycling can recycle contaminated and degraded plastics (that mechanical recycling cannot deal with) to obtain value-added products, which potentially solves the environmental problems caused by plastics and realizes a circular economy. Alkaline earth metal oxides, as a category of cost-effective and multi-functional materials, have been widely used in chemical recycling of common plastics, acting as three roles: catalyst, template, and absorbent.

Recent progress in removal of heavy metals from wastewater: A comprehensive review.

The heavy metal pollution constitutes a critical environmental issue. This has stimulated intensive efforts to develop treatment techniques for their removal from wastewater, including adsorption, membrane separation, precipitation/electrodeposition, ion exchange, coagulation-flocculation, flotation/electroflotation, solvent extraction, catalysis, and bioremediation. This article provides a comprehensive review on the advances in those techniques with the focus on the recent decade (2013-2023).

Structural transition and chemical reactivity of atomic carbon chains.

The sp-hybridized carbon chain (carbyne) is a representative 1D atomic material, whose bonding structure and chemical reactivity have remained a mystery for a century. Here, we report the unexpected alternating bond orders of 1.4 and 2.

3D graphene: synthesis, properties, and solar cell applications.

Three-dimensional (3D) graphene is one of the most important nanomaterials. This feature article highlights the advancements, with an emphasis on contributions from our group, in the synthesis of 3D graphene-based materials and their utilization in solar cells. Chemistries of graphene oxides, hydrocarbons, and alkali metals are discussed for the synthesis of 3D graphene materials.

Superstructured NiMoO@CoMoO core-shell nanofibers for supercapacitors with ultrahigh areal capacitance.

High areal capacitance for a practical supercapacitor electrode requires both large mass loading and high utilization efficiency of electroactive materials, which presents a great challenge. Herein, we demonstrated the unprecedented synthesis of superstructured NiMoO@CoMoO core-shell nanofiber arrays (NFAs) on a Mo-transition-layer-modified nickel foam (NF) current collector as a new material, achieving the synergistic combination of highly conductive CoMoO and electrochemical active NiMoO. Moreover, this superstructured material exhibited a large gravimetric capacitance of 1,282.

Turning dead leaves into an active multifunctional material as evaporator, photocatalyst, and bioplastic.

Large numbers of leaves fall on the earth each autumn. The current treatments of dead leaves mainly involve completely destroying the biocomponents, which causes considerable energy consumption and environmental issues. It remains a challenge to convert waste leaves into useful materials without breaking down their biocomponents.

3D meso/macroporous carbon from MgO-templated pyrolysis of waste plastic as an efficient electrode for supercapacitors.

Converting waste plastic into valuable carbon materials as the electrode for supercapacitors represents a sustainable way to deal with the severe waste plastic-related environmental issues. However, ideal carbon materials for supercapacitors require not only a large specific surface area but also abundant meso/macropores, which is still challenging for conventional synthesis methods. Herein, MgO-templated pyrolysis with chemical activation was demonstrated as an effective approach to convert waste polyethylene terephthalate (PET) plastic bottles into 3D meso/macroporous carbon (MMPC) with both large total surface area (1863.

Observation of Electron-Beam-Induced NaH Decomposition in Graphene Nanoreactors by Transmission Electron Microscopy.

Sodium hydride (NaH) was unprecedently embedded inside graphene nanobubbles via the discovered reaction between NaH and CO. With the graphene nanobubble as a nanoreactor for NaH, we directly observed the electron-beam-induced decomposition process of graphene-covered NaH by high-resolution transmission electron microscopy with energy dispersive spectrometry and electron energy loss spectroscopy, revealing its decomposition mechanism. This can provide guidance for the design of hydrogen storage materials.

Critical role of tetracycline's self-promotion effects in its visible-light driven photocatalytic degradation over ZnO nanorods.

Zinc oxide (ZnO), which is widely applied for ultraviolet-light driven photocatalysis, has no activity in visible-light photocatalytic process due to its large band gap of ∼3.2 eV. Herein, however, we demonstrated the multiple self-promotion effects of tetracycline as band adjuster, photo-sensitizer, and charge transfer promoter for ZnO nanorods, realizing its visible-light photocatalytic degradation with an excellent removal efficiency up to 91.

Carbonate-superstructured solid fuel cells with hydrocarbon fuels.

A basic requirement for solid oxide fuel cells (SOFCs) is the sintering of electrolyte into a dense impermeable membrane to prevent the mixing of fuel and oxygen for a sufficiently high open-circuit voltage (OCV). However, herein, we demonstrate a different type of fuel cell, a carbonate-superstructured solid fuel cell (CSSFC), in which in situ generation of superstructured carbonate in the porous samarium-doped ceria layer creates a unique electrolyte with ultrahigh ionic conductivity of 0.17 S⋅cm at 550 °C.

Thermo-photo catalysis: a whole greater than the sum of its parts.

Thermo-photo catalysis, which is the catalysis with the participation of both thermal and photo energies, not only reduces the large energy consumption of thermal catalysis but also addresses the low efficiency of photocatalysis. As a whole greater than the sum of its parts, thermo-photo catalysis has been proven as an effective and promising technology to drive chemical reactions. In this review, we first clarify the definition (beyond photo-thermal catalysis and plasmonic catalysis), classification, and principles of thermo-photo catalysis and then reveal its superiority over individual thermal catalysis and photocatalysis.

Thin-water-film-enhanced TiO-based catalyst for CO hydrogenation to formic acid.

Carbon dioxide (CO) hydrogenation can not only mitigate global warming, but also produce value-added chemicals. Herein, we report a novel three-phase catalytic system with an generated and dynamically updated thin water film covered on the noble-metal-free TiO-based catalyst for highly efficient CO hydrogenation, realizing a four-time enhancement compared with that with the catalyst suspended in water. The water film plays dual roles by directly participating in the reaction and removing the produced oxygenates (mainly formic acid) from the catalyst surface by dissolution.

Distinct Pathways in Visible-Light Driven Thermo-Photo Catalytic Methane Conversion.

The utilization of visible light for direct photocatalytic methane conversion remains a huge challenge. Here, we developed a thermo-photo catalytic process with a visible-light-responsive Pt/WO catalyst and realized highly efficient visible-light driven methane conversion for the first time. The conversion efficiency was enhanced by 4.

Highly efficient visible-light photocatalytic ethane oxidation into ethyl hydroperoxide as a radical reservoir.

Photocatalytic ethane conversion into value-added chemicals is a great challenge especially under visible light irradiation. The production of ethyl hydroperoxide (CHCHOOH), which is a promising radical reservoir for regulating the oxidative stress in cells, is even more challenging due to its facile decomposition. Here, we demonstrated a design of a highly efficient visible-light-responsive photocatalyst, Au/WO, for ethane oxidation into CHCHOOH, achieving an impressive yield of 1887 μmol g in two hours under visible light irradiation at room temperature for the first time.

Bifunctional electrocatalysts for oxygen reduction and oxygen evolution: a theoretical study on 2D metallic WO-supported single atom (Fe, Co, or Ni) catalysts.

Catalysts play a critical role in the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) for energy storage, conversion, and utilization. Herein, first-principles density functional theory (DFT) calculations demonstrated that single-metal-atom (Fe, Co, or Ni) sites can bind to the surface of 2D WO2, enhancing the adsorption of intermediates involved in the OER/ORR. Furthermore, it was found that the single-metal-atom-doped 2D WO2 achieves the smallest OER and ORR overpotentials of 0.