Chem & Bio Engineering最新文献

As an important subclass of metal–organic frameworks (MOFs), anion-pillars MOFs (APMOFs) have recently exhibited exceptional performances in separation and purification processes. The adjustment of pore sizes and environments of APMOFs can be finely tuned through judicious combination of organic ligands, anion pillars, and metal ions. Compared to widely investigated anion pillars, organic ligands are more crucial as they allow for a broader range of pore sizes and environments at the nanometer scale. Furthermore, different from the bidentate ligand-based APMOFs that typically form three-dimensional (3D) frameworks with pcu topology, APMOFs constructed using multidentate nitrogen(N)-containing ligands (with a coordination number ≥ 3) offer opportunities to create APMOFs with diverse topologies. The larger dimensions and possible distortion of multidentate N-containing ligands prove advantageous for addressing multi-component hydrocarbon separations encompassing a broad spectrum of dynamic diameters. Therefore, this Review summarizes the structural characteristics of multidentate ligand-based APMOFs and their enhanced performances for gas separation and purification processes. Additionally, it discusses current challenges and prospects associated with constructing multidentate ligand-based APMOFs while providing prospects. This critical review will provide valuable insights and guides for designing and developing advanced multidentate ligand-based APMOF adsorbents.

Catalytic conversion of carbon dioxide (CO₂) into useful chemical raw materials or fuels can help achieve the “dual carbon” goals of carbon peaking and carbon neutrality. As a sustainable green energy source, solar energy provides energy for human production and life. In recent years, the reported single-atom catalysts (SACs) have higher atom utilization and better catalytic efficiency than traditional heterogeneous catalysts. In the field of photocatalysis and photothermal synergistic catalysis of CO₂ conversion, single-atom catalysts can reduce the reaction temperature and pressure, improve the catalytic activity, and improve the selectivity of the reaction. In this mini-review, the basic mechanism and classification of CO₂ reduction are introduced, and then the roles and differences of single-atom catalysts in photocatalysis and photothermal catalysis are introduced. In addition, according to the reduction product types, the recent research progress of single-atom catalysts in photoconversion and photothermal CO₂ conversion was reviewed. Finally, the challenges of monoatomic photocatalytic and photothermal CO₂ reduction technologies have prospected. This mini-review hopes to provide an in-depth understanding of the roles of single atoms in photocatalysis and photothermal catalysis and to shed light on the actual production and application of renewable energy. High-performance single-atom catalysts are expected to achieve industrial applications of CO₂ conversion, which will contribute to the early realization of the two-carbon goal.

Ultraviolet (UV) curable shape memory polymers (SMPs) are a family of smart materials that have been widely used in four-dimensional (4D) printing due to their fine compatibility to stereolithography based additive manufacturing and superior performance in creating programmable shapeshifting. Currently, the deployment of 4D printed shape memory structure is idealized as a free recovery process, which, however, frequently leads to overestimation of shape recovery ratio in practice due to the existence of external loading or constraint. Herein, we treat the UV crosslinked SMP as a thermoviscoelastic solid and derive analytical solutions to predict the maximum recovery stress under fully constrained shape recovery and shape recovery ratio under partially constrained shape recovery. Effects of training parameters including programming strain, programming temperature, fixing temperature, storage time, recovery temperature and constraining stress have been investigated through parametric studies. Good agreement has been achieved among theoretical prediction, experimental investigation and numerical simulation. Hopefully, our model can provide a theoretical tool that quantitatively guides the design of 4D printed shape memory structures toward practical applications.

Lithium–oxygen batteries (LOBs) have received much research interest owing to their ultra-high energy density, but their further development is restricted by the erosion of the Li anode, the degradation of the electrolyte, and especially the sluggish oxygen-involving reactions on the cathode. To facilitate the oxidation of discharge products, halide redox mediators (HRMs), a subclass of soluble additives, have been explored to promote their decomposition. Meanwhile, some other intriguing functions were discovered, like protecting the Li anode and redirecting the discharge pathway to form LiOH. In this Review, after a brief introduction of LOBs and HRMs, the various functions of HRMs, not limited to promoting the oxidation of discharge products, are discussed and summarized. In addition, the challenges and controversies confronted by HRMs in LOBs are highlighted and the future opportunities of HRMs for achieving better LOBs are proposed.

Annular tetranuclear cluster based metal–organic frameworks (MOFs) have displayed unique advantages in gas adsorption and separation due to their highly connected robust architectures. Herein, two novel heterometallic tetranuclear motifs, [Y₂Cd₂(μ₃-O)₂(COO)₈(H₂O)₂] and [Y₂In₂(μ₃-O)₂(μ₂-O)₂(COO)₈(H₂O)₂], were successfully explored, which were further extended by 1,3,5-tris(4-carboxyphenyl)benzene (H₃BTB) tritopic linker to give isostructural MOFs (SNNU-326 and -327). SNNU-326 and -327 both exhibit the abilities to remove impurities (C₂-hydrocarbons and CO₂) in natural gas (NG) and excellent CH₄ storage capacities at high pressures. SNNU-326 shows better CH₄ purification and storage performance than SNNU-327 owing to different framework charges, in which only one counter ion is needed in SNNU-326 but two of them are necessary for SNNU-327, thus resulting in an obvious decrease of surface area. Dynamic breakthrough experiments demonstrate that SNNU-326 can effectively separate CH₄ from equimolar C₂H₂/CH₄, C₂H₄/CH₄, C₂H₆/CH₄, and CO₂/CH₄ mixtures with breakthrough interval times of about 40.6, 35.1, 54.2, and 10.2 min g^–1 (273 K, 1 bar, 2 mL min^–1), respectively. At the same time, SNNU-326 exhibits excellent CH₄ storage capability with total and working uptakes of 154.3 cm³ (STP) cm^–3 (80 bar) and 103.4 cm³ (STP) cm^–3 (5–65 bar) at 273 K on account of the collaborative impacts of adequate apertures, high surface areas, and multiple open metal sites.

Gas dehydration is a critical process in gas transportation and chemical reactions, yet traditional drying agents require an energy-intensive dehydration and regeneration step. Here, we present a nonporous molecular crystal called Melem that can be synthesized and scaled up through solid-state synthesis methods. Melem exhibits exceptional water selectivity in gas dehydration and can be reactivated under moderate conditions. According to the single-crystal structure and powder X-ray diffraction studies, a reversible structural transformation between Melem and its hydrated form, Melem–H₂O, induced by hydration/dehydration processes has been observed. Melem displays water adsorption properties with a maximum uptake of 11 mmol·g^–1 at p/p₀ = 0.92 and 298 K. Additionally, Melem retained consistent water capture capacities after 5 adsorption–desorption cycles. The remarkable gas dehydration performance of Melem was confirmed by column breakthrough experiments, which achieved a separation factor of up to 654.

The separation and purification of methane from natural gas are crucial chemical processes. Herein, we report a Zn-cluster-based MOF (SDMOF-3), enabling the efficient separation of mixed low-carbon alkanes. The unique Zn clusters in the MOF enhance its interaction with hydrogen atoms in alkanes, thus realizing the separation of saturated light alkanes. Single-component gas adsorption tests revealed that SDMOF-3 exhibits significantly higher affinity for C₃H₈ compared to CH₄ and C₂H₆ at 298 K. Dynamic column penetration experiments with mixed gases demonstrated the excellent separation performance of SDMOF-3 for separating C₃H₈ and C₂H₆ from CH₄.

The separation and purification of methane from natural gas are crucial chemical processes. Herein, we report a Zn-cluster-based MOF (SDMOF-3), enabling the efficient separation of mixed low-carbon alkanes. The unique Zn clusters in the MOF enhance its interaction with hydrogen atoms in alkanes, thus realizing the separation of saturated light alkanes. Single-component gas adsorption tests revealed that SDMOF-3 exhibits significantly higher affinity for C₃H₈ compared to CH₄ and C₂H₆ at 298 K. Dynamic column penetration experiments with mixed gases demonstrated the excellent separation performance of SDMOF-3 for separating C₃H₈ and C₂H₆ from CH₄.

Aqueous zinc-ion batteries (AZIBs) have recently attracted worldwide attention due to the natural abundance of Zn, low cost, high safety, and environmental benignity. Up to the present, several kinds of cathode materials have been employed for aqueous zinc-ion batteries, including manganese-based, vanadium-based, organic electrode materials, Prussian Blues, and their analogues, etc. Among all the cathode materials, manganese (Mn)-based oxide cathode materials possess the advantages of low cost, high theoretical specific capacity, and abundance of reserves, making them the most promising cathode materials for commercialization. However, several critical issues, including intrinsically poor conductivity, sluggish diffusion kinetics of Zn²⁺, Jahn–Teller effect, and Mn dissolution, hinder their practical applications. This Review provides an overview of the development history, research status, and scientific challenges of manganese-based oxide cathode materials for aqueous zinc-ion batteries. In addition, the failure mechanisms of manganese-based oxide materials are also discussed. To address the issues facing manganese-based oxide cathode materials, various strategies, including pre-intercalation, defect engineering, interface modification, morphology regulation, electrolyte optimization, composite construction, and activation of dissolution/deposition mechanism, are summarized. Finally, based on the analysis above, we provide future guidelines for designing Mn-based oxide cathode materials for aqueous zinc-ion batteries.

Interfacial solar steam generation is recognized as a promising solution to alleviate the scarcity of freshwater resources owing to its utilization of clean solar energy alongside its high efficiency and minimal heat loss. Nonetheless, the utilization of solar energy for water evaporation encounters challenges, primarily manifested in low evaporation rates and efficiency. Herein, we introduced an approach involving the development of a biomass-based hybrid engineering hydrogel evaporator, denoted as CLC (chitosan and lignosulfonate sodium hybrid hydrogel with a carbon nanotube). The construction of this evaporator involves the straightforward blending of lignosulfonate sodium (LS) and marine polysaccharide biomass chitosan (CS) with carbon nanotubes (CNT) serving as the photothermal materials. The interaction between the sulfonic group of LS and the amino group of CS with water molecules, facilitated by hydrogen bonding and electrostatic interactions, reduces the evaporation enthalpy of water, thereby lowering the energy demand for evaporation. Furthermore, the incorporation of LS reduces the thermal conductivity of the as-prepared hydrogel and promotes photothermal management to mitigate heat loss. The CLC hydrogel demonstrates an evaporation rate of 2.48 kg m^–2 h^–1 and energy efficiency of 90% under one sun illumination. Moreover, the CLC hydrogel exhibits excellent antibacterial properties (98.4%), ensuring that desalinated water meets drinking standards. This high efficiency and eco-friendly biomass hydrogel with antibiological pollution characteristics and purification abilities holds great potential for widespread application of long-term seawater desalination.