Latest ArticlesAs one of the most essential components in photocuring system, photoinitiators (PIs) exert a crucial influence on the properties of the cured product. However, commercially available PIs encounter challenges in simultaneously achieving efficient photoinitiation performance and excellent light absorption properties, significantly limiting their applications in various fields. Here, two bis-chalcones and four corresponding oxime esters (OXEs) were designed and synthesized as highly efficient PIs. Featuring a structure comprising bis-chalcone and two diphenyl sulfides, the conjugated systems in these compounds enhance their light-absorption properties in near-ultraviolet and visible region, effectively. Both the frontier molecular orbital simulations and excited state calculations suggest the contribution of sulfur atoms to electron delocalization and the formation of conjugated structure. Due to the high reactivity of the NO bond in OXE moiety, the four OXEs exhibit exceptional free radical photoinitiating ability in commercial acrylic monomers/oligomers with LED@365 nm as light source. Notably, one of them demonstrates superior performance in the photoinitiation of multifunctional crosslinker, achieving more than 70% conversion within 3 s, coupled with outstanding absorption at 365 nm. These chalcone-based OXEs are considered to exert significant potential in the realm of free radical photocuring.
The bicarbonate-formate (HCO3− – HCO2−) interconversion provides a promising cycle for a conveniently accessible hydrogen storage system via reversible dehydrogenation and hydrogenation processes. Existing catalytic systems often use organic solvents, tedious optimization as well as manipulation of pH values, solvent, pressure and various additives. Herein, we present an operational, robust, safe and cost-effective catalytic system for hydrogen storage and liberation. We have established a unique catalytic system with two different solid organometallic assemblies (NHC-Ru and NHC-Ir) that facilitate the reversible transformation between sodium formate and bicarbonate in aqueous solutions collaboratively and efficiently. Notably, the NHC-Ru catalyst is privileged for the hydrogenation of sodium bicarbonate, whereas the NHC-Ir component enables the dehydrogenation of sodium formate, all in a single reaction vessel. What sets this system apart is its simplicity. The H2 discharging and recharging is simply regulated by heating the mixture with or without H2. Remarkably, this process requires no extra additives or supplementary treatments. Moreover, the reversible hydrogen storage system is durable and can be reused for over 30 cycles without a discernible decline in activity and selectivity. The strategic paradigm in this study shows significant practical potential in hydrogen fuel cell applications.
Achieving seamless tiling through the self-assembly of organic species has long fascinated scientists for its potential applications across various fields. However, constructing periodic nanostructures with high-order tessellation remains challenging, particularly in achieving precise control at the supramolecular level. In this study, we present the successful creation of multiple seamless 2D tessellations on Au (111) surface using versatile hexagonal tiles derived from a singular molecular unit, namely 2,6,10-tribromotricycloquinazoline. Through scanning tunneling microscopy imaging, seven distinct 2D tessellations, ranging from regular to semiregular to k-uniform tilings, are unveiled at the molecular level. Density functional theory calculations provide a theoretical basis for the formation of these complex 2D tessellation, highlighting the important role of the variability of Br···Br/H contacts in facilitating complex seamless 2D tessellations on surface. This work opens avenues for exploring possibilities in constructing intricate tiling patterns with diverse applications.
Sluggish conversion reaction kinetics and spontaneous shuttle effect of lithium polysulfides (LiPSs) are deemed as the two big mountains that hinder the practical application of lithium-sulfur batteries (LSBs). Herein, dual-defect engineering strategy is implemented by introducing boron-doping and phosphorus-vacancy sites with MoP@NC composite as the precursor. Based on the experimental characterizations and theoretical calculations, B-MoP1-x@NC-based electrode presents low oxidation potential, high lithium diffusivity, small Tafel slope and strong adsorption capability for polysulfides, which is beneficial to enhance the adsorption capability for LiPSs, reduce the lithium diffusion energy barriers and Gibbs free energy for the conversion reactions of LiPSs. As demonstrated, the corresponding Li-S/B-MoP1-x@NC batteries can remain high reversible capacity of 753 mAh/g at 0.5 C after 300 cycles, and keep a stable capacity of 520 mAh/g at 0.5 C after 100 cycles even at the high-loading content of 5.1 mg/cm2. According to the results of in-situ UV–vis spectra, the satisfactory battery performance majorly originates from the existence of dual-defect characteristics in B-MoP1-x@NC catalyst, which effectively promotes the conversion reaction kinetics of LiPSs, and restrains the shuttle behavior of LiPSs. The key ideas of this work will enlighten the development of catalytic cathode materials for sulfur-based secondary batteries.
The development of stable and efficient non-noble metal cocatalysts has arisen as a promising yet challenging endeavor in the context of photocatalytic overall water splitting. In this study, NiCo alloy cocatalysts were synthesized with nickel/cobalt metal organic framework (NiCo-MOF) as source of nickel and cobalt. Systematic characterization results demonstrate the successful deposition of alloy cocatalysts onto the surface of SrTiO3. The prepared SrTiO3 loaded NiCo-alloy can generate hydrogen and oxygen in a stoichiometric ratio for photocatalytic overall water splitting, achieving an apparent quantum yield of 11.9% at 350 ± 10 nm. Theoretical calculations indicate that the introduction of cobalt has a beneficial regulatory effect on the hydrogen evolution sites of Ni, reducing the free energy of H adsorption. The synergistic catalytic effect of bimetallic catalysts contributes to enhancing photocatalytic activity and stability. This study offers constructive insights for the development of high-efficiency and cost-effective cocatalyst systems.
Utilizing superwettability micro/nanostructures to enhance the condensation heat transfer (CHT) performance of engineering materials has attracted great interest due to its values in basic research and technological innovations. Currently, exploring facile micro/nanofabrication approaches to create high-efficiency CHT surfaces has been one of research hotspots. In this work, we propose and demonstrate a type of new superwettability hybrid surface for high-efficiency CHT, which consists of superhydrophobic nanoneedle arrays and triangularly-patterned superhydrophilic microdots (SMDs). Such hybrid surface can be fabricated by the facile growth of densely-packed ZnO nanoneedles on the Zn-electroplated copper surface followed by fluorosilane modification and mask-assisted photodegradation. Through regulating the diameters and interspaces of SMDs, we obtain the optimized triangularly-patterned hybrid surface, which shows 42.7% higher CHT coefficient than the squarely-patterned hybrid surface and 58.5% higher CHT coefficient than the superhydrophobic surface. The key of such hybrid surface design is to considerably increase CHT coefficient brought about by SMD-triggered drop sweeping at the cost of slightly reducing heat transfer area of superhydrophobic functional zone for drop jumping. Such new strategy helps develop advanced CHT surfaces for high-efficiency electronic cooling and energy utilization.
The tert-butyl nitrite as a bifunctional reagent mediated radical alkene difunctionalization has emerged as a powerful strategy for synthesis of structurally diverse oxime-containing compounds. However, the phosphorus-centered radical initiated transformations remain largely elusive. Herein, a visible-light-induced radical phosphinoyloximation of alkenes with secondary phosphine oxides and tert-butyl nitrite has been developed under photocatalyst- and metal-free conditions. This protocol features mild conditions, broad substrate scope, good functional tolerance, and operational simplicity, yielding a diverse array of α-phosphinoyl oximes in moderate to good yields with high stereoselectivities. The photomediated homolytic cleavage of ONO bond of tert-butyl nitrite generates the reactive tert-butoxyl radical and persistent NO radical to act as both HAT reagent and the source of oximes.
Core-shell colloidal particles with a polymer layer have broad applications in different areas. Herein, we developed a two-step method combining aqueous surface-initiated photoinduced polymerization-induced self-assembly and photoinduced seeded reversible addition-fragmentation chain transfer (RAFT) polymerization to prepare a diverse set of core-shell colloidal particles with a well-defined polymer layer. Chemical compositions, structures, and thicknesses of polymer layers could be conveniently regulated by using different types of monomers and feed [monomer]/[chain transfer agent] ratios during seeded RAFT polymerization.
Up to now, numerous emerging methods of cancer treatment including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, immunotherapy and chemotherapy have rapidly entered a new stage of development. However, the single treatment mode is often constrained by the complex tumor microenvironment. Recently, the nanomaterials and nanomedicine have emerged as promising avenues to overcome the limitation in cancer theranostics. Especially, metal-organic frameworks (MOFs) have gained considerable interests in cancer therapy because of their customizable morphologies, easy functionalization, large specific surface area, and good biocompatibility. Among these MOFs, iron-based MOFs (Fe-MOFs) are particularly promising for cancer treatment due to their properties as nano-photosensitizers, peroxidase-like activity, bioimaging contrast capabilities, and biodegradability. Utilizing their structural regularity and synthetic tunability, Fe-MOFs can be engineered to incorporate organic molecules or other inorganic nanoparticles, thereby creating multifunctional nanoplatforms for single or combined theranostic modes. Herein, the minireview focuses on the recent advancements of the Fe-MOFs-based nanoplatforms for self-enhanced imaging and treatment at tumor sites. Furthermore, the clinical research development of Fe-MOFs-based nanoplatforms is discussed, addressing key challenges and innovations for the future. Our review aims to provide novice researchers with a foundational understanding of advanced cancer theranostic modes and promote their clinical applications through the modification of Fe-MOFs.
The nano-MOF-303 synthesized by microwave method exhibited efficient adsorption capacity (232 mg/g) toward Ag+, in which the adsorption behaviors were fitted by the pseudo-second-order kinetic and the Freundlich isotherm model. The outstanding Ag+ sorption ability of nano-MOF-303 could be contributed to electrostatic interactions, weak coordination interaction of Ag-N, and AgCl precipitates originating from the stored Cl− in nano-MOF-303. Besides the adsorbent regeneration, the formed Ag/AgCl onto nano-MOF-303 could produce Ag/AgCl/MOF-303 as a photocatalyst for sulfamethoxazole degradation under visible light. In this work, both the adsorption and photocatalysis mechanisms were clarified, which might provide insight to develop more effective adsorbents for mining the critical resource from the wastewater.
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