ChemSusChem最新文献

The natural Z-scheme of oxygenic photosynthesis efficiently drives electron transfer from photosystem II (PSII) to photosystem I (PSI) via an electron transport chain, despite the lower energy levels of PSII. Inspired by this sophisticated mechanism, we present a layered cascade bio-solar cell (CBSC) that emulates the Z-scheme. In this design, chlorophyll derivatives (Chl) act as PSI analogs, while bacteriochlorophyll derivatives (BChl) serve as PSII analogs in the active layer. The resulting photocurrent, prominently detected in the near-infrared region, is validated through external quantum efficiency measurements. Sub-nanosecond transient absorption spectroscopy reveals a prolonged charge transfer (CT) state from BChl to Chl (Chl-/BChl+ species) compared to the reverse direction (Chl+/BChl- species). This asymmetry highlights a dominant electron flow from BChl (PSII analog) to Chl (PSI analog) under simultaneous excitation, effectively replicating the natural Z-scheme electron transfer. These findings represent a significant advance in the design of bio-inspired solar cells, paving the way for artificial photosynthesis systems and offering profound insights into improving photovoltaic theory and efficiency.

Spirocyclic alkyl amino carbene (SCAAC) Ru complexes demonstrate outstanding activity and selectivity in ethenolysis of methyl oleate (MO) or fatty acid methyl esters (FAMEs), and 5,6-dimethoxyindane derivative was the most active catalyst to date. For the further catalyst design, we proposed modifying the spirocyclic fragment by fusion of saturated carbo- or heterocycle, linked to the 5,6-positions of indane or 6,7- positions of tetralin. Another suggested way of the modification of SCAAC complex was the insertion of chromane fragment to the carbene ligand. Using an alternative approach to SCAAC ligand precursors, based on hydroformylation of indenes, dihydronaphthalenes and their analogs, new SCAAC complexes were synthesized, their cis-configuration was confirmed by XRD. Comparative study of new and known selected complexes in ethenolysis of FAMEs (84 wt% MO) revealed that each of SCAAC catalysts has a temperature optimum of activity. At 60 °C 0.5 ppm of the complex containing 1,2,3,4,5,6,7,8-octahydroanthracene spirocyclic fragment provided 56 % conversion of FAMEs with TON=1.1⋅10⁶; 0.25 ppm of this complex in ethenolysis of high-purity MO demonstrated the TON ~2⋅10⁶, leading among the catalysts under study. In ethenolysis of FAMEs chromane derivative showed TON of 4-6⋅10⁵ and unprecedented temperature-independent 99.7-99.9 % selectivity at 15-60 °C.

In recent years, mechanosynthesis of peptides through either chemical or enzymatic routes has been accomplished. In part, this advancement has been driven due to the organocatalytic properties of peptide-based biomaterials. In this work, we report the merging of chemical and enzymatic protocols under mechanochemical conditions to synthesize peptide materials based on L-proline and L-phenylalanine. Compared to traditional step-by-step peptide synthesis in solution, our mechanochemical approach combining peptide coupling reagents with the proteolytic enzyme papain offers a more sustainable route by reducing the number of synthetic steps, shortening reaction times, increasing chemical yields, and minimizing waste production. Notably, the mechanosynthesized peptides exhibited organocatalytic activity in the asymmetric aldol reaction between cyclohexanone and 4-nitrobenzaldehyde.

Platform chemicals from renewable resources with broad applications are highly desirable, particularly for replacing fossil-based monomers. Bifunctional aliphatic ester-aldehydes, accessible via regioselective hydroformylation of unsaturated oleochemicals, can be converted into linear ω-amino/ω-hydroxy esters and dicarboxylic acids-key building blocks for biobased aliphatic polycondensates. However, their success hinges on efficient, economically viable production, with catalyst recycling being critical. We present the Rh-catalyzed, cyclodextrin-mediated, aqueous biphasic hydroformylation of methyl 10-undecenoate (from castor oil) and methyl 9-decenoate (from rapeseed oil) to produce methyl 12-oxododecanoate and methyl 11-oxoundecanoate, respectively, with high yields and productivity. This system allows for efficient catalyst recycling via decantation, maintaining 30 % of its native activity in aqueous biphasic conditions. Reaction conditions were optimized using a tailored experimental design, reducing nearly 200 experiments to 39 without sacrificing predictive accuracy. The optimized conditions were transferred to a continuous miniplant, achieving a low rhodium loss of 0.018 % h^-1, with excellent space-time yields of 76.5 kg h^-1 m^-3. Rhodium in the product was as low as 79 ppb, with 4.4 kg of product per mg of catalyst lost, marking a significant step in combining hydroformylation-derived, bio-based platform chemicals with economic industrial potential.

In light of the increasingly pressing energy and environmental challenges, the use of photocatalysis to convert solar energy into chemical energy has emerged as a promising solution. Halide perovskites have recently attracted considerable interest as photocatalysts due to their outstanding properties. Early developments focused on Lead-based perovskites, but their use has been severely restricted due to the toxicity of Lead. Consequently, researchers have introduced non-toxic elements to replace Lead, with common substitutes being transition metals such as Tin (Sn), Bismuth (Bi), and Antimony (Sb). Among them, Bi-based perovskites have demonstrated superior photocatalytic performance. Nevertheless, the inherent instability of perovskites and the severe recombination of charge carriers have necessitated the development of various modification strategies to enhance their performance. This Review discusses the modification strategies for Bi-based halide perovskites and illustrates the impact of these strategies on the photocatalytic performance. Finally, future research directions and challenges of Bi-based perovskites for photocatalysis are proposed.

We demonstrate the application of mechanochemistry in the synthesis of indolone-based photoswitches (hemiindigos, hemithioindigos, and oxindoles) via Knoevenagel condensation reactions. Utilizing ball-milling and an organic base (piperidine) acting as catalyst and solvent for liquid assisted grinding (LAG) conditions, we achieve rapid, solvent-free transformations, obtaining a set of known and previously unreported photoswitches, including highly functional amino acid-based photoswitches, multichromophoric derivatives and photoswitchable cavitands based on resorcin[4]arenes. The reaction under mechanochemical conditions gives moderate-to-high yields and is highly stereoselective leading to Z-isomers of hemiindigos and hemithioindigos and E-isomers of oxindoles. For selected examples, reversible visible-light photoswiching properties have been demonstrated.

The pursuit of carbon circularity in the fabrication of new materials has driven the increased use of recycled and biobased resources, a practice that has become more prevalent in recent years. In epoxy resin systems, alternatives to the use of fossil-based bisphenols have been proposed such as via the production of recycled bisphenol A (r-BPA) or by substitution with lignin derivatives, both of which are recovered from previous processes, promoting circularity. For this study, r-BPA was obtained via the chemical recycling of plastic blends from end-of-life (eol) televisions (TV). Subsequent glycidylation with epichlorohydrin (ECH) and ring-opening using acrylic acid allowed to obtain recycled bisphenol A diglycidyl ether (r-DGEBA) and bisphenol A glycerolate diacrylate (r-DAGBA), respectively. Six thermosets were fabricated by reacting Jeffamine D230 (Jeff D230) with r-DGEBA/r-DAGBA in a diverse range of epoxide:acrylate (E : A) ratios. The addition of acrylates resulted in the formation of β-amino esters (via Aza-Michael addition), which are thermo-reversible and allow the incorporation of dynamic bonds into the otherwise robust epoxy formulation. To evaluate the effect of the increasing biobased content, glycidylated depolymerized lignin (GDL) from hardwood was incorporated into the composition to produce five extra polymers. The crosslinked networks of these materials were extensively characterized, and the structure-property relationship was established by comparing their thermomechanical performance. The dissociative acrylate-amine interactions were identified under specific thermal conditions, applied systematically to program temporary shapes and analyse the crosslink reversibility of the thermosets. In summary, our findings demonstrate that recycled and biobased aromatic monomers can be incorporated to create dynamic crosslinked structures with tuneable properties, representing a step forward towards versatile, reusable, and circular materials.

The design of interfaces between nanostructured electrodes and advanced electrolytes is critical for realizing advanced electrochemical double-layer capacitors (EDLCs) that combine high charge-storage capacity, high-rate capability, and enhanced safety. Toward this goal, this work presents a novel and sustainable approach for fabricating ionogel-based electrodes using a renewed slurry casting method, in which the solvent is replaced by the ionic liquid (IL), namely 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI). This method avoids time-consuming and costly electrolyte-filling steps by integrating the IL directly into the electrode during slurry preparation, while improving the rate capability of EDLCs based on non-flammable ILs. The resulting ionogel electrodes demonstrate exceptional electrolyte accessibility and enable the production of symmetric EDLCs with high energy density (over 30Wh/kg based on electrode material weight) and high-rate performance. These EDLCs could operate at temperatures up to 180°C, far exceeding the limitations of traditional EDLCs based on organic electrolytes (1M TEABF4 in acetonitrile, up to 65°C). Ionogel-type EDLCs exhibit remarkable stability, retaining 88% specific capacity after 10000 galvanostatic charge/discharge cycles at 10Ag-1 and demonstrating superior retention compared to conventional EDLCs (50%), while also maintaining 92.4% energy density during 100h floating tests at 2.7V. These electrochemical properties highlight their potential for robust performance under demanding conditions.

Modulating the oxidation state of copper (Cu) is crucial for enhancing the electrocatalytic CO₂ reduction reaction (CO₂RR), particularly for facilitating deep reductions to produce methane (CH₄) or multi-carbon (C₂₊) products. However, Cu^δ+ sites are thermodynamically unstable, fluctuating their oxidation states under reaction conditions, which complicates their functionality. Incorporating interfacial metal oxides has emerged as an effective strategy for stabilizing these oxidation states. This review provides an in-depth examination of the reaction mechanisms occurring at oxide-modified Cu^δ+ sites, offering a comprehensive understanding of their behavior. We explore how Cu/metal oxide interfaces stabilize Cu oxidation states, showing that oxides-modified Cu catalysts often enhance selectivity for C₂₊ or CH₄ products by stabilizing Cu⁺ or Cu²⁺ sites. In addition, we discuss innovative strategies for the rational design of efficient Cu catalytic sites tailored for specific deep CO₂RR products. The review concludes with an outlook on current challenges and future directions, offering new insights into the rational design of selective and efficient CO₂RR catalysts.

Water-lean absorbents are regarded as a new generation of post-combustion CO₂ capture technology that could significantly relieve those drawbacks posed by traditional aqueous alkanolamines. However, the exponential increase in viscosity during CO₂ absorption remains an urgent issue that needs to be resolved before their practical deployment. In this work, novel water-lean amines based on biomass glycerol have been devised as single-component CO₂ absorbents with low viscosity (79~110 cP at 25  ${}^{\circ }C$ , 29~39 cP at 40  ${}^{\circ }C$ ) under high capacity (12~18 wt % at 25  ${}^{\circ }C$ , 10~17 wt % at 40  ${}^{\circ }C$ ). The captured CO₂ could be smoothly released by thermal desorption. Results from preliminary stability test and 10 absorption-desorption cycles showed that such non-aqueous absorbents had significant structural toughness as well as reusability. Spectroscopic measurements including ¹³C NMR and in situ FTIR were performed to gain mechanistic insights by monitoring the entire CO₂ absorption and desorption process, while DSC, VLE and DFT calculations provided rational interpretation for reaction kinetics and thermodynamics. The synergistic promotion of glycerol ether group on both CO₂ chemical and physical absorption was also verified under high pressure conditions.