结构化学最新文献

Organic radicals feature versatile unpaired electrons key for photoelectronic and biomedical applications but remain difficult to access in stable concentrated forms. We disclose easy generation of stable, concentrated radicals from various alkynyl phenyl motifs, including 1) sulfur-functionalized alkyne-rich organic linkers in crystalline frameworks; 2) the powders of these molecules alone; 3) simple diethynylbenzenes. For Zr-based framework, the generation of radical-rich crystalline framework was achieved by thermal annealing in the range of 300–450 °C. For terminal alkynes, electron paramagnetic resonance signals (EPR, indicative of free radicals) arise after air exposure or mild heating (e.g., 70 °C). Further heating (e.g., 150 °C for 3 h) raises the radical concentrations up to 3.30 mol kg⁻¹. For more stable internal alkynes, transformations into porous radical solids can also be triggered, albeit at higher temperatures (e.g., 250–500 °C). The resulted radical-containing solids are porous, stable to air as well as heat (up to 300–450 °C) and exhibit photothermal conversion and solar-driven water evaporation capacity. The formation of radicals can be ascribed to extensive alkyne cyclizations, forming defects, dangling bonds and the associated radicals stabilized by polycyclic π-systems.

Rationally constructed new catalyst can promote carbon dioxide reduction reaction (CO₂RR) to valuable carbonaceous fuels such as formate and CO, providing a promising strategy for low CO₂ emissions. Herein, the synthesized Ni₃S₂@C as a highly efficient electro-catalyst exhibits remarkable selectivity for formate with 73.9% faradaic efficiency (FE) at −0.7 V vs. RHE. At high applied potential, it shows a high syngas evolution with CO/H₂ ratios (0.54–3.15) that are suitable for typical downstream thermochemical reactions. The experimental and theoretical analyses demonstrate that the electron-rich Ni²⁺ in Ni₃S₂ enhances the adsorption behavior of ^∗OCHO intermediate, reduces the energy barrier of the formation of intermediates, and improves the selectivity of the formate product. Attenuated total reflection surface-enhanced infrared absorption spectra conducted in situ show that ^∗OCHO intermediate is more likely to be generated and adsorbed on Ni₃S₂, enhancing the selectivity and activity of the formate product.

Solar light driven hydrogen production from water splitting and oxidation of biomass-derivatives is attractive for the conversion of solar energy to high value-added chemicals. The fabrication of heterostructure photocatalysts with matched band structure between two semiconductors is a promising approach for efficient photocatalysis. In this work, a novel In₂O₃/In₂S₃ heterostructured hollow fiber photocatalyst was successfully fabricated through two-step ion exchange and chemical bath deposition methods, where the In₂S₃ nanoparticles (NPs) anchored on the surface of In₂O₃ hollow fibers via strong interfacial interaction between the In₂O₃ (222) and In₂S₃ (220) facets. The photocatalyst was used for efficient visible-light-driven photocatalytic hydrogen production integrated with selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). Compared with pristine In₂O₃ and In₂S₃, the optimal In₂O₃/In₂S₃ heterostructure exhibits an enhanced photocatalytic hydrogen production rate (111.2 μmol h⁻¹ g⁻¹), HMF conversion efficiency (56%) and DFF selectivity (68%) under visible light irradiation. The experimental and theoretical investigations illustrate the phase interface between well matched In₂O₃ (222) and In₂S₃ (220) facets gives rise to facilitated photogenerated charge separation and transfer. This study presents the development of high-performance heterostructured photocatalysts for high efficient hydrogen production coupled with biomass oxidation.

The escalating emissions of greenhouse gases into atmosphere have precipitated a host of ecology and environmental concerns. Electrochemical reduction of CO₂ (CO₂RR) is emerging as a sustainable solution for effectively addressing these issues. Leveraging the cost-effectiveness and eco-friendly attributes, Bi-based catalysts have been extensively studied with the purpose of enhancing activity and stability. This minireview majorly overviews the research advancements in Bi-based catalysts for CO₂ electrocatalysis towards formic acid/formate production. Initially, we offer a concise overview of the reaction pathways involved in electrochemical CO₂ reduction. Subsequently, we summarize the progress in various types of electrolysis cells and associated influencing factors. Specifically, the electronic structure modulation strategies of Bi-based catalysts including oxide-derived bismuth, bismuth-based chalcogenides, bimetallic and high-entropy compounds, etc. have been highlighted. Future research endeavors are poised to delve deeper into comprehending system dynamics during the reaction process to achieve exemplary stability high energy efficiency under industrial conditions.

As an emerging class of inorganic hybrid materials, salt-inclusion chalcogenides (SICs) have garnered significant attention in the past decade owing to their distinct host-guest structural characteristics and outstanding performance in the field of optoelectronics. In this study, a novel quaternary SIC [Cs₁₄Cl][Tm₇₁Se₁₁₀] has been discovered using an appropriate flux method. The structure comprises two distinct parts within the lattice: the host [Tm₇₁Se₁₁₀]¹³⁻ framework and the guest [Cs₁₄Cl]¹³⁺ polycation. Notably, this structure reveals the presence of mixed-valent Tm²⁺/Tm³⁺ and different types of closed cavities for the first time. Additionally, thermal transport performance testing shows that it has ultralow thermal conductivity, ranging from 0.29 to 0.24 W/m⋅K within the temperature range of 323–673 K, which is one of the lowest reported values among polycrystalline chalcogenides. This research not only advances the coordination chemistry of rare-earth-based compounds but also reaffirms that SIC semiconductors are promising systems for achieving ultralow thermal conductivity.