ACS Sustainable Chemistry & Engineering最新文献

Alkali metal borate molten salts have emerged as efficient high-temperature liquid CO₂ sorbents, advancing carbon reduction for energy-intensive industrial chemical processes. This work investigated the relationship between the liquidus behavior and CO₂ uptake characteristics of lithium–sodium borates, M_xB_1–xO_1.5–x (M = Li_0.5Na_0.5), over a composition range of 0.50 ≤ x ≤ 0.80. Differential Scanning Calorimetry (DSC) measurements revealed detailed phase–transition profiles, with liquidus temperatures ranging from 500 to 650 °C. Composition-dependent liquidus behavior governs the CO₂ sorption characteristics during the early sorption stages, transitioning from “solid-to-liquid” in low-alkali to “liquid-to-liquid” in high-alkali regions. Optimal working capacities and reaction rates consistently correspond to the liquidus transition range, minimizing energy demands for preserving molten state in the cyclic CO₂ capture-release operations. These findings establish temperature–composition operating windows tailored to industrial needs, providing critical liquidus diagrams and demonstrating their potential as versatile sorbents for high-temperature CO₂ capture.

Enhancing local electric fields (LEFs) near catalytic centers is a pivotal strategy to elevate electrocatalytic efficiency by accelerating electron transport and ion enrichment. Herein, a high-performance nanocomposite multifunctional electrocatalyst with high-curvature nanostructures was designed to generate strong LEFs, addressing slow reaction kinetics and high thermodynamic barriers. Ultrasmall vanadium nitride (VN) and cobalt–nickel alloy (CoNi) nanocomposite electrocatalyst systems were constructed by incorporating polyethylenimine (PEI) as a soft template and polyoxometalates (POMs) as precursors. This approach effectively prevents nanoparticle agglomeration and enhances active site exposure. Finite-element simulations revealed that the ultrasmall CoNi-VN nanoparticles generated strong LEFs, significantly enhancing electron transport and ion concentration around active sites. Meanwhile, the integrated ultrahigh-specific surface area, heteroatom doping, and effective mass transfer of the carbon nanotube structure endowed CoNi/VN/BNCNT with excellent HER (η₁₀, 109 mV), OER (η₅₀, 362 mV), and ORR (E_1/2, 0.85 V) activities. The rechargeable Zn–air batteries achieved a high specific capacity of 810 mAh g^–1, a peak power density of 220 mW cm^–2 at 350 mA cm^–2, a high open-circuit voltage of 1.51 V, and a low charging/discharging voltage gap of 0.89 V. Moreover, CoNi/VN/BNCNT requires cell voltages of 1.52 and 1.67 V to achieve current densities of 10 and 50 mA cm^–2 for water splitting. This work addresses the agglomeration of alloy and VN nanoparticles while regulating the intensity of the local electric field, providing a promising pathway for advanced energy conversion and storage technologies.

Sodium valproate is a well-established drug in neurology, serving as an antiepileptic, migraine prophylactic, and mood stabilizer. According to the World Health Organization, an estimated 50 million people worldwide are affected by these conditions. Continuous pharmaceutical manufacturing offers significant advantages, including consistent drug quality, cost and time efficiency, and the flexibility to scale production to meet rising patient demand. In this work, we present a compact flow synthesis of sodium valproate using inexpensive diethyl malonate, eliminating the need for solvent exchange and intermediate purification. The process features a novel dipropylation reaction with propyl chloride, a simple deethoxycarbonylation step without relying on corrosive acid-mediated decarboxylation, and sequential basic hydrolysis and salification. After an in-line extraction to remove impurities, sodium valproate was obtained with a total yield of 87% and a purity of over 99%, all achieved within a residence time of just 41 min, resulting in a throughput of 552 g/day. The green metrics for this method, with a process mass intensity of 11.8 and an E-factor of 10.8, are significantly lower than those of the current batch production process, demonstrating a more sustainable approach.

Dimethyl carbonate (DMC), a widely used green chemical, has garnered significant attention. Chlorine-free catalytic technology for the carbonylation of methyl nitrite (MN) to DMC has considerable potential for various applications. Currently, research efforts are concentrated on improving the performance of Pd–NaY catalysts. The Lewis acidity and pore structure of the molecular sieve determine the distribution of the Pd species and their electronic structure. In this paper, a strategy of continuous acid–base treatment was employed to design a novel catalyst. It was found that the rearrangement of skeleton Si and Al occurred after the acid–base treatment, which regulated the acidity of the NaY molecular sieve. Additionally, a new mesoporous structure appeared that facilitated the transport of reactants and products. The regulation of NaY molecular sieve acidity enabled more efficient utilization of the active Pd species, helped maintain the Pd species in their oxidation state, and promoted the formation of the active intermediate species *COOCH₃, thereby improving the catalytic performance. The DMC yield of the PdCu/Y-CAT catalyst reached 1591 g·kg_cat^–1·h^–1. Acid–base treatment is an efficient method to design metal-zeolite catalysts, which facilitates the industrial application of chloride-free catalysts in the MN carbonation of the DMC route.

Understanding the structure–activity relationships in perovskite catalysts is essential for advancing renewable electrochemical energy technologies. This study reports the exceptional performance of LaMnO₃ deposited on nickel foam (NF) electrodes in selective methanol electrooxidation. Experimental analyses reveal that the preferred crystalline facets of LaMnO₃ grown on nickel foams predominantly generate {110} facets, and this facet engineering effectively promotes the adsorption of methanol molecules. Moreover, the electronic structure of the Mn–O bonds on the LaMnO₃ surface has been optimized, resulting in good activity and approximately 100% Faradaic efficiency (FE) at current densities ranging from 100 to 500 mA cm^–2. Notably, the total FE for formate demonstrates durability for up to 10 h at 100 mA cm^–2, with selectivity exceeding 86%. This results in a substantial reduction (∼15.88%) in energy consumption for producing pure hydrogen. In situ studies indicate that the unique structure of LaMnO₃/NF facilitates the formation of high-valent active Mn–O species and stabilizes the crystalline framework through an interfacial Mn–O network. This configuration provides abundant active sites and oxygen sources for converting methanol to formate, establishing a stable and efficient catalytic environment.

The carbon content acting as either a support or a protection layer is critical for the catalytic performance of Pt-based catalysts used for proton exchange membrane fuel cells. And, the highly active Pt-based catalysts often include an annealing process during the preparation. However, transferring fresh postannealed catalysts to air faces safety challenges since metal nanoparticles can catalyze the oxidation of the carbon content in the catalyst to generate a large amount of heat in a short time. The released heat, in turn, can raise the sample temperature and accelerate the oxidation reaction. Thus, to ensure processing safety and catalyst quality, the conventional method is complicated, time-consuming, and extreme-caution-required. Here, we report a simple and time-efficient method for transferring annealed catalysts to air together with the capability of optimizing the catalytic performance. With this method, we reduced the processing time from 180 to 10 min (saving 94.4%) without sacrificing the performance of prepared catalysts and achieved a scale-up preparation of up to 11 g per batch. Additionally, the prepared catalyst (PtCo/CB-60s-L_Pt) delivered a mass activity of 0.77 A/mg and a rated power of 12.8 W/mg, both of which are higher than the targets set by the United States Department of Energy. The achieved performance proved that the prepared catalyst is among the top-tier catalysts reported in practical fuel cell tests. Thus, the reported method is promising for reducing the process cost and guaranteeing the quality for industrial production of highly active catalysts.

The Na₄Fe₃(PO₄)₂P₂O₇ (NFPP) cathode exhibits great potential for low-cost, high-safety, and long-life Na-ion batteries, yet lattice distortion at a high voltage of >3.1 V easily causes irreversible Na-ion extraction/insertion in pentagonal pyramid position (Na4 site). Herein, we forecast the elemental doping site according to the deviation degree and then realize the successful occupation of Li ions in Na4 sites of NFPP. The density functional theory calculations and experimental results verify that the Li ions in Na4 sites are not involved in the de/sodiation process but effectively hinder the shift of Fe along the a-axis and the distortion of P₂O₇ dime with well-maintained Na-ion diffusion paths even under high operation voltages. Consequently, Li-doped NFPP delivers an ultrahigh initial charge capacity of 128.7 mAh g^–1 (theoretical value: 129 mAh g^–1) with a Coulombic efficiency of 87.9%. It also exhibits a superior capacity retention of 95.7% after 150 times at 1C with a predictively long-term cycle life of 80% after 5589 h. The increase in energy density of Fe-based phosphate cathodes is reckoned to further accelerate their large-scale applications in energy storage systems.