Latest ArticlesMulti-stimuli responsive materials controlled and coupled by two or more channels have a broad range of applications in the field of switches, memories, and molecular machines. The exploration of the material is currently focused on the pure organic system, which limits the development of such materials greatly. In this work, we present a new chiral organic-inorganic hybrid salt, (R-3-hydroxypyrrolidinium)2[Fe(CN)5(NO)] (1), which exhibits rare multi-stimuli responsive behaviors in thermal, mechanical and optical channels. In detail, 1 undergoes a C2-P21221 phase transition deriving from the thermal motion of organic cations with the increase of temperature, but the reverse transition can only be induced by mechanical pressure. Moreover, polycrystalline hybrid salt showed photo-responsive performance, i.e., the ground-state N-bound nitrosyl ligand adopts two configurations in excited states caused by light in 532 nm irradiation, accompanying with a photo-induced structural transformation of the anionic framework. Namely, the thermal motion characteristics of organic cations, the photoresponse characteristics of anionic inorganic skeleton and the pressure characteristics from hydrogen bonds are simultaneously integrated in 1. This unprecedented coupling mechanism of multi-stimuli responses makes 1 a potential candidate for future multichannel data storage applications.
Most photodynamic therapies (PDT) rely on reactive oxygen species (ROS) produced by type Ⅱ mechanisms. However, since the production of type Ⅰ ROS is not limited by oxygen content, making it more favorable for antimicrobial phototherapy in complex microenvironments. Herein, we report a substituent cationization design strategy that not only improves the hydrophilicity of the prepared phthalocyanine molecule, but also promotes the electron transfer process in the photosensitizer, resulting in the strong type Ⅰ photodynamic effect of the phthalocyanine self-assembled photosensitizer to efficiently generate O2•- under both normal and hypoxic conditions. This in combination with its excellent bacteria recognition capability derived from the cationic part on its surface and intrinsic photothermal therapy effect of the phthalocyanine macrocycle endows the phthalocyanine self-assembled photosensitizer with excellent phototherapeutic antimicrobial properties in preclinical models, effectively promoting the wound healing process. This work provides a promising strategy for designing efficient multi-mode photosensitizers.
Control of subsurface interstitial atoms in transition metals is an effective approach to modulate selectivity in hydrogenation reactions. In this study, nickel was alloyed with gallium to form Ni3Ga, thereby regulating the octahedral interstitial sites. Subsequently, carbon atoms were introduced into the Ni3Ga (forming Ni3GaC0.5) via thermal treatment in an acetylene atmosphere, leading to a significant enhancement in selectivity for acetylene hydrogenation reaction. The X-ray diffraction and transmission electron microscopy results demonstrate an increase in the lattice parameter due to the incorporation of carbon atoms and the uniform distribution of carbon in Ni3GaC0.5 nanoparticles. The obtained Ni3GaC0.5/oCNT catalyst exhibits significantly improved selectivity in acetylene hydrogenation reaction, with approximately 82% ethylene selectivity at 98% conversion. Furthermore, it maintains good selectivity at various hydrogen-to-alkyne ratios and displays good stability during long-term operation. The introduction of carbon suppresses the formation of the subsurface hydrogen structure under reaction conditions. Additionally, the charge transfer between carbon and nickel results in the electron deficiency of nickel, effectively inhibiting the over-hydrogenation pathway and enhancing the selectivity. These results provide insights for the design of non-precious metal catalysts in selective hydrogenation reactions.
The design of pnictide nonlinear optical crystals is quite different from chalcogenide and oxide those, in which a new paradigm need be developed to regulate the band gap, one of key optical parameters. In this work, two non-centrosymmetric halidepnictides, [Cd2P]2[CdBr4] (CPB) and [Cd2As]2[CdBr4] (CAB) were reported. The complete octet binding electrons of pnictogens were constructed by four Cd-P polar covalent bonds under the anchoring effect of halogens, creating an extremely flat valence band maximum with band dispersion of only 0.17 eV. As expected, the balance of the covalency and ionicity in CPB and CAB was successfully realized, leading to a wide band gap of 2.58 eV and 1.88 eV. Remarkably, CPB not only has a widest band gap among Cd-containing pnictides, but also exhibits a SHG effect of 1.2 × AgGaS2, moderate birefringence (0.088@visible light and calcd. 0.043@2050 nm) and a wide IR transmission range. This is the first time that the octet binding electrons construction strategy was utilized to design non-diamond like NLO pnictides with excellent performances.
The prototype material, Li1.23Ru0.41Ni0.36O2, is proposed to gain the deep and comprehensive understanding of chemical and structural changes of the novel layered/rocksalt intergrown cathodes. Synchrotron-based X-ray absorption spectra and resonant inelastic X-ray scattering reveal that both cationic and anionic redox evolves in the charge compensation process of the intergrown material, while synchrotron-based extended X-ray fine structure spectra and in situ X-ray diffraction measurements demonstrates that the intergrown material undergoes minimal local- and long-range structural variations at deep de/lithiation. This work highlights the great potential of the intergrown structure to inspire the design of advanced cathode materials for lithium-ion batteries.
The usage of flexible ligands in constructing MOF materials (FL-MOFs) has been widely studied due to its numerous advantages, including the structural diversity, polynuclear MOFs, transmitting magnetic exchanges, enantioselective separation, asymmetric catalysis, etc. However, the field still faces challenges in deeply understanding the effect of ligand configuration on the properties of these materials. Here, we employ a flexible aggregation-induced emission ligand (4,4′-((1E, 1′E)-anthracene-9,10-diylbis(ethene-2,1-diyl))dibenzoic acid) with great mechanical stability to construct FL-MOFs to lock the ligand configuration to explore the pressure-induced evolution of the ligand with coordination restriction, involving changes in fluorescence and intermolecular interaction. In-situ high-pressure fluorescence, Raman, and FT-IR experiments have revealed that the intermolecular interaction of AIE-Mn-MOF with configuration restriction increased more rapidly than that of free AIE-L. This discovery offers valuable insights for synthesizing MOF materials with exceptional mechanical stability and significantly advances our understanding of the impact of coordination restriction in FL-MOFs on their response to external stimuli.
BA2(MA)n-1PbnI3n+1 series low-dimensional (2D) perovskites have been widely investigated for their remarkable environmental stability, but still suffer the poor light absorption and disordered phase distribution, hindering their practical applications. In this work, we combine the introduction of FA and the addition of PbCl2 to optimize the film quality, strengthen the light absorption, regulate internal phase distribution, and promote carrier transport inside 2D perovskite films. The incorporation of FA promotes sufficient light absorption and improve the film crystallinity. Furthermore, the addition of PbCl2 eliminates the low n phase (n = 1) and suppresses the forming of the low n phase of n = 2, enhancing the film conductivity and diminishing carrier recombination. The synergistic of A-site cation engineering and phase manipulation achieves a high efficiency of 16.48%. Importantly, the synergistic prepared perovskite film does not show any changes after 60 days in the air with an average humidity of 57% ± 3%, and the corresponding solar cell maintains 85% of the original efficiency after more than 800 h, demonstrating remarkable environmental stability. The results indicate that the synergistic of A-site cation engineering and phase manipulation is promising for producing superior efficiency, along with satisfying humidity stability.
Graphene-like materials and metal-organic framework (MOF) materials hold significant promise for advanced energy systems. However, the accumulation of two-dimensional (2D) material and the low conductivity of MOF have seriously affected their practical application. The universal method for synthesizing homogeneous nitrogen-doped graphene-like carbon/metal-organic framework (N-GLC/MOF) composites, including N-GLC/MOF-74, N-GLC/ZIF-8, N-GLC/Cu-BTC, and N-GLC/FeCo-PBA was presented. Thanks to the synergistic effect of the two components, the N-GLC/MOF-74 composite exhibits a specific capacitance of 470.18 F/g at 1 A/g and maintains a coulombic efficiency of 95.04% at 5 A/g over 5500 cycles. Our work lays a solid foundation for the design and synthesis of N-GLC-based composites. We anticipate that this research will furnish valuable insights for the advancement of N-GLC/MOF composites, with a primary focus on enhancing supercapacitor performance.
The increasing demand for energy density pushes LiCoO2 (LCO) to work at higher voltage (≥4.5 V), which brings a series of problems including detrimental phase transition and structural instability. Various elemental doping has been proven an effective strategy to improve its structure stability. However, the understanding of elemental doping homogeneity effect is not enough, whether in terms of the controllability of doping homogeneity or its complex consequences. In this work, LCO powders with different Al doping homogeneity were synthesized and tested under high voltage (≥4.5 V) in both half and full cell at room and high temperature, respectively. The results show that the Al homogeneously doped LCO showed better cycling stability and rate performance compared to the inhomogeneous LCO sample. Particularly, the discharge capacity of Al homogeneously doped LCO after 500 cycles under 4.5 V in full cells could reach 160.1 mAh/g at 1.0 C with 94.1% capacity retention. Postmortem characterization demonstrates that a better doping homogeneity favors the stability of both the bulk and interface as well as the kinetic conditions. This study provided new insights about LCO performance fading, which sheds new light on the development of high-voltage LCO products
Highly active cathode catalysts for efficient formation/decomposition of Li2O2 are essential for the performance improvement of lithium-oxygen batteries (LOBs). In this study, a grain-refining Co0.85Se catalyst with a lattice spacing of 2.69 Å of (101) plane closely matching with the (100) plane (2.72 Å) of Li2O2 was applied for high-performance LOBs. Highly (101) plane exposed Co0.85Se@CNT was synthesized by a simple one-pot hydrothermal method. The Co0.85Se with the lattice matching effect not only led to the efficient conversion and polarized growth of Li2O2, but also prevented the formation of byproducts. Density functional theory (DFT) calculations reveal that Co0.85Se (101) plane has the intrinsic catalytic ability to generate/decompose Li2O2 during ORR/OER process, due to its homogeneous electron distribution, suitable adsorption energy, and promoted Li2O2 growth kinetics. As a consequence, the (101) plane highly exposed Co0.85Se@CNT-80 electrode exhibited remarkable cycle stability over 2400 h at 100 mA/g and 290 cycles at 500 mA/g, which is about 2 times longer than other electrodes.