ChemSusChem最新文献

A novel class of resource-efficient, woven-glass-grid current collectors (CCs) for Li-ion batteries is introduced. These CCs are based on ultra-light multifilament glass threads, woven to a grid and surrounded with a thin metal layer (equivalent to a 1 µm-thick metal foil) in a roll-to-roll physical vapor deposition process. This saves > 90% of the required Cu and Al metals and reduces the mass of the CCs by > 80%. At the same time, the gravimetric capacity of anodes with graphite and cathodes with LiCoO2 active material increases by 48% and 14%, respectively, while full cells are characterized by an increase of 26%. Thus, the specific energy can be improved by 25%. A complete anode and cathode fabrication process from preparing the CCs and electrodes to cells is described and demonstrated in coin cell format. Coin cells with woven-glass-grid CCs achieved 300 cycles with a capacity retention of 93%, a Coulombic efficiency of > 99.9%, and a higher rate capability until a C-rate of 3C. This technology opens up new possibilities for designing ultralight CCs with dedicated surface properties for Li and beyond Li batteries.

Recently, atomically precise metal nanoclusters (NCs) have been widely applied in CO₂ reduction reaction (CO₂RR), achieving exciting activity and selectivity and revealing structure-performance correlation. However, at present, the efficiency of CO₂RR is still unsatisfactory and cannot meet the requirements of practical applications. One of the main reasons is the difficulty in CO₂ activation due to the chemical inertness of CO₂. Constructing symmetry-breaking active sites is regarded as an effective strategy to promote CO₂ activation by modulating electronic and geometric structure of CO₂ molecule. In addition, in the subsequent CO₂RR process, asymmetric charge distributed sites can break the charge balance in adjacent adsorbed C₁ intermediates and suppress electrostatic repulsion between dipoles, benefiting for C-C coupling to generate C₂₊ products. Although compared to single atoms, metal nanoparticles, and inorganic materials the research on the construction of asymmetric catalytic sites in metal NCs is in a newly-developing stage, the precision, adjustability and diversity of metal NCs structure provide many possibilities to build asymmetric sites. This review summarizes several strategies of construction asymmetric charge distribution in metal NCs for boosting CO₂RR, concludes the mechanism investigation paradigm of NCs-based catalysts, and proposes the challenges and opportunities of NCs catalysis.

Redox biocatalysis is an essential pillar of the chemical industry. Yet, the enzymes' nature restricts most reactions to aqueous conditions, where the limited substrate solubility leads to unsustainable diluted biotranformations. Non-aqueous media represent a strategic solution to conduct intensified biocatalytic routes. Deep eutectic solvents (DESs) are designable solvents that can be customized to meet specific application needs. Within the large design space of combining DES components (and ratios), hydrophobic DESs hold the potential to be both enzyme-compatible - keeping the enzymes' hydration -, and solubilizers for hydrophobic reactants. We explored two hydrophobic DESs, lidocaine/oleic acid, and lidocaine/decanoic acid, as reaction media for carbonyl reduction catalyzed by horse liver alcohol dehydrogenase, focusing on the effect of water contents and on maximizing substrate loadings. Enzymes remained highly active and stable in the DESs with 20 wt % buffer, whereas the reaction performance in DESs outperformed the pure buffer system with hydrophobic substrates (e. g., cinnamaldehyde to form the industrially relevant cinnamyl alcohol), with a 3-fold specific activity. Notably, the cinnamaldehyde reduction was for the first time performed at 800 mM (~100 g L^-1) with full conversion, which opens up new avenues to industrial applications of hydrophobic DESs for enzyme catalysis.

The challenge of moving to a carbon-free energy economy is highlighted in the context of technology and materials restrictions. Many technologies needed for the so-called energy transition depend on critical metals such as platinum, lithium, iridium and cobalt. Here we focus on solid borohydride salts as hydrogen carriers, studying catalysts for hydrogen release. We combine metal 3D printing technology and a Raney-type leaching process to make structured macroscopic catalyst/reactor monoliths of cobalt, aluminium and stainless steel with well-defined micropores. Remarkably, the blank catalyst samples, which are made only from aluminium and stainless steel (Al-SS), show high activity and, importantly, high stability in borohydride hydrolysis, with no mass loss and no surface poisoning. The batch results are confirmed in a continuous setup running for 96 h. Catalyst performance is attributed to the stable porous structure, the mechanical stability of the stainless steel macrostructure, and the presence of accessible Al(OH)x sites. This research shows a clear contribution to sustainability based on multi-factor comparison: The Al-SS catalyst outperforms the state-of-the-art on mechanical and chemical durability, it is both PGM-free and CRM-free, and its preparation follows a simple, scalable and low-waste procedure.

Transition metal-catalyzed cross-coupling reaction between organometallic reagents and electrophiles is a potent method for constructing C(sp²)-C(sp³) bonds. Given the characters of organometallic reagents, cross-reductive coupling is emerging as an alternative strategy. The resurgence of electrochemistry offers an ideal method for electrochemical reductive of cross-coupling electrophiles. Inspired by the mechanism of electrochemical metal hydride, our study proposed that Ni-H electrochemically catalyze the hydroarylation coupling of unactivated alkenes with aryl halides. 1,1-Diarylalkanes can be produced effectively. This method have advantages including mild conditions, excellent regioselectivity, and satisfactory yields.

Catalytic hydrocracking of polyethylene to branched liquid fuels has drawn particular attention. Here, bifunctional Pt/Nb₂O₅ catalysts with different Pt loadings were prepared for polyethylene hydrocracking. It was found that the low-loading Pt/Nb₂O₅ catalysts exhibited significantly higher catalytic activity than those of high-loading Pt/Nb₂O₅ catalysts, with the 0.2Pt/Nb₂O₅ catalyst having the best catalytic performance (79.2 % yield of liquid fuels (C₅-C₁₉) with branched alkanes accounting for 85.2 %). Detailed characterizations revealed that the activation of H₂ played a crucial role in the efficient hydrocracking of polyethylene. The 0.2Pt/Nb₂O₅ catalyst, with highly dispersed Pt nanoclusters on the surface, facilitated the highly active H^δ- species formation, thereby enhancing hydrocracking activity. This work highlights the importance of H₂ activation in the hydrocracking of polyethylene and provides insights for the design of efficient catalysts.

Supercapacitors are crucial in renewable energy integration, satellite power systems, and rapid power delivery applications for mitigating voltage fluctuations and storing excess energy. Aqueous electrolytes offer a promising solution for low-cost and safe supercapacitors. However, they still face limitations in cycle life and wide-temperature range performance. Here, we present a symmetric supercapacitor utilizing activated carbon electrodes and a "water-in-salt" electrolyte (WiSE) based on lithium perchlorate. The WiSE electrolyte exhibits an expanded electrochemical stability window, endowing the aqueous supercapacitor with remarkable stability and long cycle life of over 100,000 cycles at 500 mA g^-1 with more than 91 % capacity retention. Moreover, the supercapacitor demonstrates good rate capability and wide temperature operability ranging from -20 to 80 °C. The use of high concentrations of salt in the aqueous electrolyte contributes not only to the enhancement of supercapacitor performance and cycle life but also to the temperature stability range, enabling all-season operability.

Chemical upcycling of plastic wastes into valuable chemicals is a promising strategy for resolving plastic pollution, but economically viable methods currently are still lacking. Here, we report one-pot hydrogenolysis of PET plastic into p-xylene with an excellent yield (99.8 %) over a robust non-precious Cu-based catalyst, CuZn/Al₂O₃, in the absence of alcohol solvents. The presence of Zn species promotes the dispersion of Cu⁰ and increases the ratio of Cu⁺/Cu⁰, whereas the synergistic effect of Cu⁰ and Cu⁺ leads to a superior performance in the conversion of PET. The combination of GC-MS, ¹³C CP MAS NMR, 2D ¹H-¹³C CP HETCOR NMR spectroscopy and kinetic studies for the first time demonstrates 4-methyl benzyl alcohol as an important reaction intermediate in the hydrogenolysis of PET. Mechanistic studies indicate that the conversion of PET mainly follows a hydrogenolysis process, involving the cleavage of ester bonds to alcohols and the C-O bond cleavage of alcohols to alkanes. This work not only brings new insight for understanding the upgrading pathway of PET, but also provides a guidance for the design of high-performance non-precious catalysts for the chemical upcycling of plastic wastes.

FeNi-based hybrid materials are promising oxygen evolution reaction (OER) catalysts for water electrolysis in hydrogen generation. In this work, the coordination tuning of FeNi-HMT frameworks was achieved by simply changing the Fe/Ni ratios using hexamethylenetetramine (HMT) as an organic ligand, and the derived hybrid FeNi catalysts with varied compositions were probed for OER. Incorporating varying amounts of Fe³⁺ by adjusting the Ni/Fe ratio results in different metal-organic framework (MOF) structures, and higher Fe feed leads to the formation of amorphous structures due to the coordination structure destruction from the weaker coordination capacity of Fe³⁺ compared to Ni²⁺ combining with the tertiary amine ligand. Among them, the FeNi-HMT (with the Fe/Ni molar ratio of 1/1) derived catalyst, consisting of Fe_0.36Ni_0.64 alloy/Ni_0.4Fe_2.6O₄ spinel oxide heterostructures supported by graphitized carbon matrix, exhibits the highest OER performance. The unique structure facilitates significant electron transfer at the alloy/spinel interface due to the large work function difference between each phase. This strong electronic effect downshifts the d-band center of the catalyst and optimizes the binding energies to the crucial oxygenated intermediates, thereby promoting the OER kinetics. This work highlights the importance of the coordination tuning of FeNi-HMT frameworks for highly efficient catalyst development.

The molten-salt-mediated oxidative dehydrogenation (MM-ODH) of ethane (C₂H₆) via a chemical looping scheme represents an effective carbon capture and utilization (CCU) method for the valorization of ethane-rich shale gas and concurrent mitigation of carbon dioxide (CO₂) emissions. Here, stepwise experimentation with Li₂CO₃-Na₂CO₃-K₂CO₃ (LNK) ternary salts (i) assessed how each component of the LNK mixture impacted ethane MM-ODH performance and (ii) explored physicochemical and thermodynamic mechanisms behind melt-induced changes to ethylene (C₂H₄) and carbon monoxide (CO) yields. Of fifteen screened LNK compositions, nine exhibited ethylene yields greater than 50 % at 800 °C while maintaining C₂H₄ selectivities of 85 % or higher. LNK salts rich in Li₂CO₃ content yielded more ethylene and CO on average than their counterparts, and net CO₂ capture per cycle reached a maximum of ~75 %. Extended MM-ODH cycling also demonstrated long-term stability of a high-performing LNK medium. Density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations suggested that the molten salt does not directly activate C₂H₆. Meanwhile, an empirical model informed by experimental data and reaction thermodynamics adequately predicted overall MM-ODH performance from LNK composition and provided insights into the system's primary drivers.