ChemSusChem最新文献

The Front Cover illustrates an innovative approach towards the valorization of aqueous side-streams in biorefineries. Light oxygenated compounds in these complex aqueous effluents are condensed over water-resistant Sn-Ti mixed oxides into hydrocarbons and aromatics under moderate process conditions. These catalysts show a robust rutile phase with hydrophobic characteristics and optimized acid properties, based on Lewis acid sites. The artwork symbolizes how heavier products spontaneously form an upper organic phase layer that can be further processed into biofuels. More information can be found in the Research Article by A. Fernández-Arroyo and M. E. Domine (DOI: 10.1002/cssc.202401761). Cover design: M. L. Martínez.

The Cover Feature shows a carbon and silicon composite catalyst (Ru/DGC) synthesized from distiller′s grains and used for the catalytic hydrogenation of phenol to cyclohexanol. Under optimal reaction conditions (1.0 MPa H₂, 60 °C, 30 min), both the phenol conversion and cyclohexanol yield reached 100 %. The outstanding stability of the catalyst and its high activity under mild reaction conditions make Ru/DGC suitable for industrial applications. More information can be found in the Research Article by Z. Jiang, B. Shi and co-workers (DOI: 10.1002/cssc.202401910).

The Cover Feature illustrates a photothermally driven loop of ammonia decomposition and synthesis with cobalt-based MOF-derived catalysts. By efficiently breaking ammonia to produce hydrogen and synthesizing ammonia from its elements, these catalysts enable a sustainable closed-loop process, showcasing ammonia′s potential as a clean and renewable hydrogen carrier. More information can be found in the Research Article by J. Gascon, A. Bavykina and co-workers (DOI: 10.1002/cssc.202401896).

Aqueous zinc-metal batteries (AZMBs) are emerging as a promising green and low-cost energy storage solution, distinguished by their high safety and environmental friendliness. However, the industrialization of AZMBs is currently hindered by significant challenges, particularly uncontrollable dendritic growth and side reactions at the zinc metal anode interface, which severely limit their large-scale application. To address these issues, salt-based electrolyte additives have emerged as a straightforward, economical, and practical solution. This review systematically classifies and analyzes the working mechanisms of inorganic, organic, and ammonium salt-based additives, elucidating their roles in regulating solvation structures, hydrogen bond networks, pH levels, interfacial protective layers, electric fields, and Zn2+ deposition behaviors. These additives enhance anode stability and mitigate side reactions, thereby improving overall electrochemical performance. Additionally, the review offers valuable insights into future directions for the development of salt-based electrolyte additives, providing essential guidance for advancing research in this field.

The transport of hydroxide in anion exchange membranes (AEMs) is generally determined by multiple factors, including hydration levels, pore morphologies, and the hydration shells of cationic groups and hydroxides. Thus, clarifying the working mechanisms would benefit the proposal of strategies for enhancing the hydroxide transport, thereby enabling a rational design of high-performance AEMs. Herein, by using ReaxFF MD simulations and RDAnalyzer, we explored the straightforward but effective correlations for steric hindrance versus hydration shell, hydration level versus Free/Associated diffusion, and strong (short) hydrogen bond (SHB) versus Vehicular/Grotthuss diffusion. Our theoretical investigations indicate that higher steric hindrance of cationic groups results in less water in the first hydration shell of cationic groups in AEMs. Meanwhile, a higher hydration level facilitates wider hydrophilic pores of AEMs and increases the ratio of the Free diffusion mechanism of hydroxides. Interestingly, we found a strong correlation between the number of SHBs and the Grotthuss diffusion, thereby enhancing the understanding of the high conductivity of COF-based AEMs that contain obvious SHBs. This work provides a theoretical view for fine-tuning the Free/Associated and Vehicular/Grotthuss transport of hydroxide in AEMs.

The parasitic hydrogen evolution reaction (HER) hinders electrolyte transport. It reduces the effective electrochemical surface area in the negative half-cell of vanadium redox flow batteries (VRFBs), resulting in substantial efficiency losses. We investigated the formation and evolution of hydrogen bubbles within VRFB electrodes through comprehensive experimental characterization and a detailed analysis of the resolved bubbles. The electrode was imaged using synchrotron X-ray tomography, and gas bubbles in the images were identified and characterized using a deep learning model combined with a morphological analysis tool. The HER intensity increases at more negative working electrode potentials, causing residual bubbles to grow and fuse in the electrode central region. In contrast, independent bubbles predominantly form at the electrode edges. Furthermore, the bubble growth leads to the gradual development of irregular shapes. These observations provide insights into bubble formation and evolution rules, contributing to a better understanding of the system.

This review critically examines the dual nature of chlorine as both an indispensable base chemical and a potential risk. Chlorine and its by-product hydrogen chloride play essential roles in the production of pharmaceuticals, plastics, agrochemicals, and disinfectants. However, their inherent toxicity, risks of handling, and environmental impacts necessitate a reassessment of their use and sustainability. The review explores emerging and established chlorine-free technologies, such as the hydrogen peroxide to propylene oxide (HPPO) process and phosgene-free routes for polycarbonate production, evaluating their potential to reduce reliance on chlorine. For applications where chlorine remains indispensable, innovations such as trichloride- and bichloride-based Ionic Liquids provide safer storage and handling options for chlorine and hydrogen chloride, respectively. These Ionic Liquids not only enhance safety but also support renewable energy integration through their potential as indirect energy storage solutions. While chlorine is unlikely to be fully replaced in the near future, ongoing innovations in chlorine-free processes and safer technologies may redefine its industrial use, contributing to a more sustainable and secure chemical industry.

While recent advancements in electrocatalysts have led to significant progress toward the commercialization of electrochemical energy conversion devices, performance degradation derived by airborne impurity remains a critical challenge to address. In particular, chloride (Cl-) poisoning of platinum (Pt) catalysts remains a critical challenge for performance. Herein, we demonstrate an effective strategy for suppressing Cl- poisoning from the perspective of ionomer layer engineering. From the hybrid interface of cation and anion exchange ionomers, the local microenvironment at the catalyst surface was modified, resulting in significant suppression of Cl- poisoning. In-situ inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that the local Cl- concentration at the Pt surface decreased by 40% compared to the bulk concentration. These findings highlight the synergistic role of the hybrid ionomer interface in suppressing Cl- poisoning, validating its effectiveness in maintaining activity and mitigating Pt dissolution. This ionomer engineering approach provides a promising pathway for improving the reliability of electrocatalytic systems under challenging operational conditions.

Ionic liquids are promising candidates for electrolytes for next generation energy storage and conversion systems. However, a high viscosity of the IL, hampering the ion transport, has led to strategies based on the dilution of the IL with a low viscosity solvent. Here we report on the influence of the addition of water to a protic ionic liquid to form a hybrid electrolyte suggested for supercapacitor applications. Our experiments directly test predictions from previous molecular dynamics simulations on this and other protic IL/water hybrid electrolytes. From small angle X-ray scattering and IR spectroscopy we show that water is inserted in the ionic matrix both as single molecules and in small aggregates. Water molecules hydrogen bond to the available proton on the ionic liquid cation and effectively separate the ion pairs, resulting in an increase in the charge correlation distance. The change in the local structure is also reflected in the local dynamics probed by neutron spin-echo spectroscopy. We reveal a local diffusive-type process that correlates well with macroscopic ion transport, e.g., the ionic conductivity. The results from neutron scattering also infer that the different local environments created by the addition of water have a relatively short lifetime.

The dynamic covalent networks (DCNs), featuring dynamic covalent bonds (DCBs) formed through isocyanate-involved chemistry, potentially contributes to a circular economy in polyurea and polyurethane industries, due to the inherent recyclability of DCNs. Over the past decade, remarkable progress has been made in the development of isocyanate-derived DCBs (IdDCBs) for the synthesis of recyclable DCNs, aiming to substitute conventional, non-recyclable materials. Here, we delve into the fundamental aspect of the IdDCB-related chemistries reported to date, and find that their reversibility is governed by electronic and steric effects. This discovery encourages us to structure the review into three sections. The first section examines the reversibility of various IdDCBs through the lens of electronic and steric influences. Our findings show that the reversibility of some IdDCBs is driven by a single chemical effect, with the examples of steric effect contributing to the dynamic behavior of thiourethanes and hindered ureas, while other cases of reversibility arise from a combination of two or more chemical effects. The knowledge thus established allows to categorize and discuss the technologically relevant DCNs, with particular emphasis on how these chemical effects influence their recyclability. Finally, the review concludes by highlighting several potentially impactful research directions that merit further exploration.