ChemSusChem最新文献

We designed six zinc phthalocyanine derivatives (ZnPc-1–ZnPc-6) as molecular semiconductors. By adjusting peripheral substituents with differing electron-donating and -withdrawing properties (–C(CH₃)₃, –O(CH₂)CF₃, –CF₃), we rationalized solubility, energy levels, and molecular arrangement to influence interfacial charge dynamics and thus device performance. Among the derivatives, ZnPc-2 with three tert-butyl groups and a trifluoroethoxy provides favorable energy level alignment, better thin film coverage, and high conductivity suited to be used as hole-selective materials. When integrated into n–i–p architecture perovskite solar cells, it measures a power conversion efficiency approaches that of Spiro-OMeTAD under our lab conditions. ZnPc-2 showed ambient operational stability, maintaining around 80% of its initial J_MPP over 24 h without encapsulation. Our combined theoretical and experimental assessment revealed detailed electro-optical properties to substantiate the influence of molecule design on the device performance. Specifically, three tert-butyl groups with a trifluoroethoxy arm outperform, evidencing molecular design as a strategy to modulate properties.

Electrocatalytic CO₂ reduction offers a promising route to decarbonize the chemical industry by coupling renewable electricity with carbon utilization. Recent progress has achieved industrially relevant activities and selectivities, yet large-scale deployment remains hindered by challenges beyond catalyst development. System-level factors-including anodic-cathodic product pairing, reactor architectures defined by membrane choice, and electrolyte regulation-critically determine efficiency, stability, and economic viability. In this Concept, we highlight these interrelated aspects and use an automated coelectrolysis strategy that integrates CO₂ electrolysis to formate with chlorine evolution as an illustrative case. This approach underscores the importance of pairing product design with reactor engineering and electrolyte management. Together, these principles provide a framework for bridging laboratory demonstrations with sustainable and economically viable implementation of CO₂ electrolysis at scale.

An efficient, electrochemical three-component reaction for the synthesis of vinyl sulfonamides from cinnamic acids, SO₂, and amines is reported. This metal-free protocol utilizes inexpensive graphite electrodes and easy-to-use SO₂ stock solutions to facilitate a decarboxylative transformation under mild conditions. The reaction proceeds with high regio- and stereoselectivity. The use of cinnamic acid derivatives as biobased feedstocks, combined with the demonstrated scalability and electrode/electrolyte reusability, highlights the potential of this approach for a sustainable synthesis of the important vinyl sulfonamide scaffold.

Nickel Sulfides have emerged as promising electrocatalysts for alkaline hydrogen evolution reaction (HER) due to their cost-effectiveness and high catalytic activity. While growing research has focused on the initial catalyst design, less attention has been paid to structural and electrochemical modifications during prolonged HER operation. Understanding these transformations is essential for developing more active and stable nickel sulphide-based HER catalysts. This study investigated the post-HER evolution of various nickel sulphide crystalline catalysts, including NiS, NiS₂, Ni₃S₂, and Ni₃S₄, after prolonged cyclic voltammetry (CV) cycling and constant current polarization. Upon 500 CV sweeps, Raman spectroscopy confirmed structural phase transformation of all nickel Sulfides toward Ni₃S₂, i.e., the most HER-active phase, irrespective of their initial chemical composition. This electrochemical activation process led to an improvement in electrochemical surface area and charge-transfer properties. Moreover, the kinetic analysis indicated a shift in the rate-determining step from a Volmer-limited mechanism to a mixed Volmer-Heyrovsky pathway, contributing to enhanced HER kinetics. Sulfur leaching was identified as a key factor in this transformation, facilitating surface restructuring and exposure of active Ni sites to the electrolyte. Importantly, post-stability characterization confirmed that leaching occurs predominantly during initial activation and ceases thereafter, with no further structural changes over prolonged operation.

The excessive discharge of phosphorus into aquatic systems is a major environmental concern, contributing to eutrophication and biodiversity loss. This study investigates the reuse of electric arc furnace slag (EAF-slag), an abundant steelmaking byproduct, as a low-cost, upcycled adsorbent material for phosphorus removal and recovery, in line with circular economy and sustainable waste management principles. The slag, rich in calcium and reactive oxides, was extensively characterized using Raman spectroscopy, scanning electron microscopy, and X-ray fluorescence, and tested for phosphate adsorption across a wide range of concentrations (5-400 mg/L) and solid-liquid ratios (from 1:10 to 1:50 expressed as g of slag in mL of P-solution). Excellent removal efficiency was achieved under all conditions, with complete phosphate uptake and a maximum sorption capacity of 10.97 mg/g at S/L = 1:30. Post-adsorption analyses (Raman mapping, X-ray photoelectron spectroscopy, and cross-sectional energy-dispersive X-ray spectroscopy) confirmed the formation of hydroxyapatite on the slag surface. Importantly, the performance of EAF-slag was also evaluated in more complex aqueous systems containing phosphate, nitrate, and sulfate ions (50 and 100 mg/L each). The phosphate adsorption capacity remained unaffected, and the slag simultaneously removed nitrate and sulfate, confirming its multifunctional sorption behavior. Additional recycling experiments demonstrated that the spent slag can be reused after resting, maintaining satisfactory phosphorus removal efficiency (≈60%) even after 5 or 10 days. Moreover, the hydroxyapatite-enriched slag showed potential for use as a fertilizer, enabling phosphorus recovery and reuse. These findings demonstrate the potential of EAF-slag as an effective, low-cost, and sustainable material for phosphorus recovery and valorization of secondary raw materials, laying the groundwork for its future application in wastewater treatment and environmental remediation.

Zeolite Beta catalysts were explored in the benzylation of lignin-based model 4-ethylphenol to produce 2-benzyl-4-ethylphenol, an important high-density precursor for jet-fuel blending. For optimal catalytic attributes, a combined dealumination-surfactant templating was deployed to obtain Zeolite Beta, with higher Si/Al ratio (∼33-39) and integrated mesoporosity. The extent and quality of mesopores were tuned by varying CTAB quantity (0.01-0.06 M) at a fixed NH₄OH concentration (0.5 M). The enhanced templating action of CTAB micelles at higher CTAB concentrations created uniform intracrystalline mesopores of 3.5 nm. This mesopore generation was predominantly directed by healing of excess SiO^- defects associated with Al vacancies at higher CTAB concentrations as evidenced by silanol speciation study using DRIFTS. Further, ²⁷Al MAS-NMR and DRIFTS (Al-OH) revealed the loss and subsequent recovery patterns of framework Al during the dealumination and surfactant templating process, respectively. Eventually, large mesopores with a higher fraction of reinstated Brønsted acidity were generated in the CTAB-templated Beta catalysts, especially at higher CTAB concentrations (0.03 and 0.06 M). Dealuminated Beta templated with 0.06 M CTAB showed the highest benzyl alcohol conversion (∼29%), the highest selectivity for 2-benzyl-4-ethylphenol (∼42%), and the lowest dibenzyl ether selectivity (∼20%). Improved performance was attributed to its large uniform mesopores, highest Brønsted-to-Lewis acid ratio (B/L) and recovered superstrong acid sites.

Nitrosocarbonyl species (NOCs), also known as acylnitroso species, are highly reactive nitrogen-containing electrophiles. Since their first reports in the 1970s, they have shown significant synthetic potential for the preparation of aminated substrates. Their widespread adoption as versatile amination reagents began in the 2000s, driven by the development of new organometallic and organocatalytic systems. NOCs are typically generated in situ from stable precursors, such as hydroxamic acids and N-hydroxycarbamates, under oxidative conditions, in the presence of a scavenging substrate. This review highlights recent advances in NOC-based catalytic aminations over the past two decades. Specifically, their catalytic generation using oxygen, reactive oxygen species, and peroxides, followed by a subsequent capture through nitroso Diels-Alder, nitroso-ene, and nitroso-aldol reactions are comprehensively discussed. While most catalytic systems rely on Fe-, Co-, Ni-, Cu-, Mo-, Ru-, and Ir-based catalysts, emerging approaches include organocatalysis, photoredox catalysis, electrochemistry, and enzymatic systems. Sustainability and innovative process technologies are also discussed as future directions.

The growing demand for bio-based and biodegradable plastics has intensified interest in producing polyhydroxyalkanoates (PHAs). Short- and medium-chain-length (SCL-MCL)-PHA copolymers are particularly attractive because of their enhanced flexibility and desirable thermal properties. However, their high-level production from inexpensive carbon sources, such as glucose derived from lignocellulosic biomass, remains challenging, largely due to limited precursor supply and inefficient polymerization. Here, we report high-level de novo production of SCL-MCL-PHAs from glucose in metabolically engineered Escherichia coli. We employed a modular metabolic engineering strategy comprising three modules: 1) construction of the 3-hydroxybutyryl-CoA monomer pathway; 2) enhancement of fatty acid biosynthesis to strengthen MCL-fatty acyl-CoA supply; and 3) screening of PHA synthases with broad substrate specificity. PHA synthase (PhaC) variants from Pseudomonas sp. MBEL 6–19 were identified to efficiently polymerize both SCL and MCL monomers. Fed-batch cultures of the engineered strains achieved two distinct outcomes: one strain produced 82.88 g L⁻¹ PHA with 5 mol% MCL fraction, while another accumulated 17.35 g L⁻¹ PHA with 19.52 mol% MCL fraction. Notably, these values fall within the 5–20 mol% MCL fraction range allowing good polymer applications, underscoring the industrial relevance of our results. This modular approach provides a versatile framework for tunable, sustainable production of SCL-MCL-PHAs.

A versatile solvent-free Wittig olefination of sugars via mechanochemistry is reported, tolerating common protecting groups as well as unprotected substrates. The method efficiently delivers structurally diverse olefins under mild and solvent-free conditions. Subsequent solvent-free late-stage modifications of the olefins demonstrate the potential of the methodology for greener sugar-based synthetic sequences.

Aromatic aldehydes hold significant value in food additives and the valorization of biorefineries. This study investigated the oxidative conversion of five guaiacol-type compounds—eugenol, isoeugenol, ferulic acid, 4-ethyl-2-methoxyphenol, and 2-methoxy-4-propylphenol—to vanillin in sodium hydroxide and nitrobenzene solutions. We thoroughly examined the effects of temperature, oxidant, and C4 substituents on vanillin yield. Our results demonstrate that at 180°C for 1 h, eugenol and isoeugenol, both possessing alkenyl functional groups, exhibited exceptionally high vanillin yields of 90.8% and 91.7%, respectively. In contrast, 4-ethyl-2-methoxyphenol and 2-methoxy-4-propylphenol, featuring saturated side chains, yielded significantly lower amounts of vanillin, at 36.8% and 24.7%, respectively. Further density functional theory calculations confirmed that the alkenyl side chain and strong structural symmetry of the C4 substituent in guaiacol-type compounds lead to lower reaction energy barriers, thereby facilitating the reaction.