Chemistry of Materials最新文献

The structure–property relationships of metal–organic framework (MOF)-based solid-state electrolytes are not well understood. Herein, a systematic investigation of 12 Zr(IV)-based UiO-66 MOFs with varying ether-chain functional groups was carried out to elucidate the critical microscopic interactions that facilitate improved solid-state electrolyte performance. Enhanced sampling molecular dynamics (MD) simulations were employed and revealed a three-tier ion hopping mechanism: linker–linker hopping, linker-counterion hopping, and counterion-counterion hopping. Detailed structural analysis of the MD trajectories revealed that the chemistry and morphology of the linker groups affect the relative stability and population distribution of the electrolyte components, such that crown-ether-based linker groups enhance the probability of extended, low-barrier ion percolation pathways. As a result, we were able to tune the ionic conductivities by rationally manipulating the counterion distributions, linker binding strengths, and the configurational entropy (multivariability of the linkers). The resulting performance of these MOF-based solid-state electrolytes was significantly enhanced, with a methoxy-functionalized framework (UiO-66-L1₁₀₀) achieving high ionic conductivities of 2.32 × 10^–4 S/cm and 2.07 × 10^–3 S/cm at 30 °C and 90 °C, respectively, an order of magnitude greater than other all-solid-state MOF electrolyte systems. The electrolyte stability was evaluated with LiIn|LPSCl|MOF:LiTFSI|LPSCl|LiIn symmetric cells, showing excellent Li plating/stripping processes for over 2 months.

Future soft materials and polymer chemistries will require innovative nonpetroleum sourcing pathways. While leveraging microbial metabolites derived from biological feedstocks possesses high potential in many avenues of chemical development, the applicability of this paradigm to the specifics of soft materials chemistry is unclear. Here, we construct a chemical reaction network based on databases of common microbial metabolites and the USPTO reaction set to examine what is possible in the chemical space of metabolite-derived chemistries of relevance to soft materials. We observe that the accessible chemical space of our chemical reaction network possesses strong microbe-specific chemical diversity and that this space saturates rapidly within three synthetic steps applied to the original microbial metabolites. Importantly, we show that the chemical space accessible from metabolite precursors possesses significant overlap with existing petrochemical building blocks, known and proposed synthetically feasible polymer monomers, and the chemical space of common organic semiconductors and redox active materials. The biases induced by the metabolite and reaction databases that parametrize our reaction network are analyzed as a function of chemical functional groups, and pathways toward broader sets of chemistries and reactions are outlined. This work introduces a computational framework for soft materials discovery with the potential to accelerate the identification of soft materials relevant to metabolic engineering targets and nonpetroleum sourcing pathways for existing soft materials.

Cadmium zinc sulfide pigments (Cd_xZn_1–xS) have been extensively used in art and industry for their bright colors. However, concerns exist over their long-term chemical stability. Due to their semiconductive properties under light exposure, these compounds may trigger photocatalytic processes that can lead to degradation issues in artworks. This study aims to replicate and compare the historical wet and dry synthesis of Cd_xZn_1–xS pigments and investigate their photocatalytic behavior, specifically their reactivity and ion leaching predispositions. Using adapted historical methods, we synthesized a series of Cd_xZn_1–xS pigments and fully characterized them using a range of analytical techniques. Their photocatalytic activity was evaluated against methylene blue dye under simulated sunlight, alongside a concomitant assessment of metal ion leaching. These experiments provide valuable insights into the historical pigments photocatalytic behavior, proposing key indicators of pigment reactivity in real artworks and demonstrating the origin of the inherent instability of historically synthesized pigments, particularly those made via wet methods. Under solar simulation, cubic nanosized pigments with 20% and 40% zinc content exhibit the highest degradation activity. This process is accompanied by the leaching of Cd²⁺ and Zn²⁺ ions, which may contribute to the formation of undesirable secondary products. The same pigments exhibited ion leaching even in the dark, although at significantly lower levels.

The design of oxygen carriers is essential for the chemical looping partial oxidation of methane (CL-POM) in syngas production. LaFeO₃ is a promising oxygen storage material, but the impact of its morphology on the reaction characteristics and mechanisms in CL-POM remains unclear. Herein, we synthesized and characterized LaFeO₃ samples with diverse morphologies (cube, porous microsphere, irregular nanoparticle, and polyhedron) to explore how morphology governs crystal plane exposure, oxygen vacancy formation, and oxygen migration. Results showed that cubic LaFeO₃ not only achieved outstanding oxygen storage capacity (4.18 mmol/g), 2.5 times that of the other three samples combined (1.64 mmol/g), but also demonstrated superior methane reactivity with good low-temperature activity (initial reaction temperature of 500 °C) and the highest methane conversion (78.26% at 750 °C). This impressive performance is due to the synergy between oxygen vacancies and the (110) crystal plane, which optimizes oxygen release and enhances methane adsorption and dissociation. DFT calculations further confirmed that the (110) plane has lower energy barriers for reaction processes than the (100) plane, and more oxygen vacancies enhance reactivity and oxygen migration. This work underscores the pivotal role of LaFeO₃ morphology in advancing the design of oxygen storage materials and a redox catalyst.