Industrial Chemistry & Materials最新文献

The synthesis of gold nanoparticles (Au NPs) was carried out by utilising the pulsed laser ablation in liquids (PLAL) method with a microchip laser (MCL) system. This portable system features low power consumption and a giant-pulse laser. Aqueous solutions with and without the surfactant poly(N-vinyl-2-pyrrolidone) (PVP) were used for laser ablation of a bulk gold rod to achieve the successful formation of a colloidal solution of Au NPs. The gas bubbles formed by heating the aqueous medium around the surface of the gold target significantly reduced the efficiency of Au NP ablation. This effect was more pronounced and prolonged in high-viscosity solutions, hindering energy transfer from subsequent laser pulses to the target. Additionally, it was suggested that the chain length of PVP does not affect either the size of the Au NPs or the ablation efficiency. Videography experiments were conducted to explore the ablation mechanism employed by the MCL system. The relatively short pulse duration of the MCL system may contribute to the formation of NPs with consistent size, which were suppressed to grow in significantly smaller cavitation bubbles with short lifetimes.

Keywords: Pulsed laser ablation in liquids (PLAL); Microchip laser (MCL); Gold nanoparticles; Viscosity; Poly(N-vinyl-2-pyrrolidone) (PVP).

Anode materials for Li-ion batteries (LIBs) utilized in electric vehicles, portable electronics, and other devices are mainly graphite (Gr) and its derivatives. However, the limited energy density of Gr-based anodes promotes the exploration of alternative anode materials such as silicon (Si)-based materials because of their abundance in nature and low cost. Specifically, Si can store 10 times more energy than Gr and also has the potential to enhance the energy density of LIBs. Despite the many advantages of Si-based anodes, such as high theoretical capacity and low price, their widespread use is hindered by two major issues: charge-induced volume expansion and unreliable solid electrolyte interphase (SEI) propagation. In this detailed review, we highlight the key issues, current advances, and prospects in the rational design of Si-based electrodes for practical applications. We first explain the fundamental electrochemistry of Si and the importance of Si-based anodes in LIBs. The excessive volume increase, relatively low charge efficiency, and inadequate areal capacity of Si-based anodes are discussed to identify the barriers in enhancing their performance in LIBs. Subsequently, the use of binders (e.g., linear polymer binders, branched polymer binders, cross-linked polymer binders, and conjugated conductive polymer binders), material-based anode composites (such as carbon and its derivatives, metal oxides, and MXenes), and liquid electrolyte construction techniques are highlighted to overcome the identified barriers. Further, tailoring Si-based materials and reshaping their surfaces and interfaces, including improving binders and electrolytes, are shown to be viable approaches to address their drawbacks, such as volume expansion, low charge efficiency, and poor areal capacity. Finally, we highlight that research and development on Si-based anodes are indispensable for their use in commercial applications.

Keywords: Lithium-ion battery; Silicon-based anode; Volume expansion; Solid electrolyte interphase propagation; Binders; Composite anode materials.

Aqueous zinc-ion batteries (ZIBs) have attracted great research interest for use in large-scale energy storage devices due to their inherent safety, environmental friendliness, and low cost. Unfortunately, dendrite growth and interfacial side reactions during the plating/stripping process triggered by uneven electric field distribution on the surface of the Zn anode seriously hinder the further development of aqueous ZIBs. Here, practical and inexpensive sodium tartrate (STA) is used as an electrolyte additive to construct a stable electrode–electrolyte interface, in which STA adsorbs preferentially on the Zn metal surface, contributing to promoting homogeneous Zn deposition. Moreover, STA interacts more strongly with Zn²⁺, which takes the place of the water molecules in the solvated shell and prevents the development of side reactions. In symmetrical cells and full cells, flat Zn anodes can therefore demonstrate remarkable cycle stability, opening the door for the development of cost-effective and effective electrolyte engineering techniques.

Keywords: Zinc ion battery; Electrolyte additive; Zinc dendrites; Hydrogen evolution reaction; Anode protection.

The physicochemical properties of metal–organic frameworks (MOFs) are closely dependent on the topology, pore characteristics, and chemical composition, which can be tuned through targeted design. Relative to direct synthesis, the post-synthesis methods of MOFs, including ion exchange, ligand replacement as well as destruction, provide a significant increase in their application range and potential. A method based on the coordination bond cleavage of MOFs has been proved to be very effective in modulating the structure and was evaluated for its application in the flame retardant field. Herein, the construction of peculiar MOF structures is categorized based on flame-retardant features through the cleavage of coordination bonds at the molecular level, and the corresponding MOFs exhibit superior flame-retardant and smoke-suppressing properties. Different approaches are highlighted to achieve coordination bond breaking to modulate MOFs properties, involving chemical composition, topology, and pore structure. This review systematically summarizes and generalizes the direct construction of high-efficiency MOF-based flame retardants based on the structure–activity relationship and their further functionalization through coordination bond cleavage, as well as the associated challenges and prospects. It is also hoped that this work will quickly guide researchers through the field and inspire their next studies.

Keywords: Metal–organic frameworks; Fire retardancy; Molecular cleavage; Coordination bond; Flame retardant mechanism.

Photocatalytic hydrogen (H₂) production coupled with selective oxidation of organic compounds into high-value-added organic intermediates has expansive prospects in the utilization and transformation of solar energy, which meets the development requirements of green chemistry. In this work, high-efficiency hole cocatalyst PdS-decorated In₂S₃ flower-like microspheres are fabricated for the effective visible-light-driven C–N coupling of amines to imines coupled with H₂ evolution. Owing to the establishment of the internal electric field, which further boosts the transfer of photoexcited holes to PdS, PdS–In₂S₃ exhibits distinctly enhanced photocatalytic redox performance, which is 39.8 times higher for H₂ and 14.3 times higher for N-benzylidenebenzylamine than that of the blank In₂S₃, along with high selectivity and stability. Furthermore, the practicability of dehydrogenation coupling of various aromatic amines to the corresponding C–N coupling products on PdS–In₂S₃ has been demonstrated and a plausible reaction mechanism has been proposed. This work is anticipated to stimulate further interest in establishing an innovative photoredox platform for selective organic synthesis coupled with H₂ evolution in a green and sustainable way.

Keywords: In₂S₃; Photoredox dual reaction; Hydrogen evolution; Visible light; Hole cocatalyst.

Gold nanoparticles (NPs) exhibit remarkable catalytic activity in low-temperature CO oxidation and their performance is highly dependent on size and shape. However, the underlying mechanism isn't fully understood yet. Herein, we combine density functional theory calculations, a multiscale structure reconstruction model, and kinetic Monte Carlo simulations to investigate the activity and structure sensitivity of Au NPs under different reaction conditions. The results indicate that increasing the partial pressure ratio of O₂ to CO leads to the decrease of optimal reaction temperature accompanied with the increase of performance. At low temperatures, the morphology of the NPs evolves to expose a higher proportion of (110) facets to promote the activity significantly. Moreover, the size dependence analysis suggests that O₂-rich conditions are favorable for small-sized NPs, while CO-rich conditions favor the large-sized NPs. These findings not only enrich our basic understanding of the structure–reactivity relationship and the origin of structure sensitivity in gold-catalysis, but provide a guide for rational design of Au catalysts.

Keywords: Kinetic Monte Carlo; CO oxidation; Gold catalysis; Nanoparticles.

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) have the unique advantages of fast electrode reaction kinetics, high CO tolerance, and simple water and thermal management at their operating temperature (120–300 °C), which can effectively solve the hydrogen source problem and help achieve the dual-carbon goal. The catalysts in HT-PEMFCs are mainly Pt-based catalysts, which have good catalytic activity in the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR). However, in HT-PEMFCs, the high load of platinum-based catalysts to alleviate the limitation of strong adsorption of phosphoric acid (PA) on the platinum surface on activity expression leads to high cost, insufficient activity, decreased activity under long-term operation and carrier corrosion. The present review mainly summarizes the latest research progress of HT-PEMFCs catalysts, systematically analyzes the application of precious metal and non-precious metal catalysts in HT-PEMFCs, and unveils the structure–activity relationship and anti-PA poisoning mechanism. The current challenges and opportunities faced by HT-PEMFCs are discussed, as well as possible future solutions. It is believed that this review can provide some inspiration for the future development of high-performance HT-PEMFC catalysts.

Keywords: High-temperature proton exchange membrane fuel cells; Cathodic oxygen reduction; Anti-phosphoric acid poisonous; Pt group metal catalysts; Non-precious metal catalysts.

Zeolites possess unique sieving properties that offer a high selectivity for removing pollutants, such as per- and polyfluoroalkyl substances (PFAS). However, there are limited studies examining the efficacy of zeolites as PFAS sorbents. Previous literature explores the effects of certain frameworks and the silica alumina ratio (SAR), and only one study has shown the effect of silanol defects on the hydrophobicity of the adsorbent. Since most zeolites are synthesized in hydroxide media, this leads to formation of silanol defects, which increase hydrophilicity with a greater effect than the inclusion of non-Si T atoms. It is critical that specific characterizations be performed to demonstrate the specific effects of different properties of the zeolites. In particular, synthesis, modification, and/or repair in fluoride media can be used to increase the hydrophobicity of zeolites by reducing silanol defects, and increasing Lewis acidity.

Keywords: Zeolites; Aqueous adsorption; PFAS; Hydrophobic interaction; Silica–alumina ratio.

Coupling the effects of flexoelectricity with piezoelectricity has been proved to effectively harvest mechanical energy. In this study, a composition-graded core–shell structure (HAP@FAP) was prepared by surface-gradient F-doping in hydroxyapatite, which could introduce flexoelectricity by a built-in strain gradient. A flexoelectric-boosted piezoelectric response was demonstrated by piezoresponse force microscopy (PFM) characterization, showing that the piezoelectric constant of HAP@FAP was increased by 2.25 times via a lattice strain gradient induced by chemical heterogeneities derived from the unique composition-graded core–shell structure. Thus, the piezocatalytic activity of HAP@FAP for phenanthrene (PHE) degradation in soil was enhanced. This work provides a new strategy for the modification of piezoelectric catalysts for the remediation of organics-contaminated soils on industrial land.

Keywords: Hydroxyapatite; Flexoelectricity; Piezocatalysis; Gradient doping; Soil remediation.

Quality testing costs hinder the large-scale production of PEM fuel cell systems due to long testing times and high safety measures for hydrogen. While eliminating both issues, electrochemical impedance spectroscopy at low hydrogen concentrations can provide valuable insights into fuel cell processes. However, the influence of high anode stream dilutions on PEM fuel cell performance is not yet completely understood. This study presents a new equivalent circuit model to analyze impedance spectra at low hydrogen partial pressures. The proposed model accurately describes the impedance response and explains the performance decrease at low hydrogen concentrations. First, the reduced availability of hydrogen at the anode leads to rising reaction losses from the hydrogen side. Further, the resulting losses lead to potential changes also influencing the cathode processes. The findings indicate that impedance spectroscopy at low hydrogen partial pressure might provide a reliable fuel cell quality control tool, simplifying production processes, reducing costs, and mitigating risks in fuel cell production.

Keywords: PEM fuel cells; Electrochemical impedance spectroscopy; EIS; Large scale PEMFC production; Anodes; Cathodes.