Accelerated sonochemical fabrication of MIn2S4 (M = Zn, Mg, Ni, Co) for ultra-high photocatalytic hydrogen peroxide production.

Ternary metal sulfide (MIn2S4) by virtue of large extinction coefficient, suitable band gap and stability, has been proposed as a candidate for photocatalytic synthesis hydrogen peroxide (H2O2). However, MIn2S4 is conventionally synthesized by solvothermal method that is generally characterized by tedious operational steps and long reaction time. In this work, four sonoMIn2S4 (M = Zn, Mg, Ni, Co) were successfully prepared by sonochemical method within 2 h. These as-synthesized sonoMIn2S4 delivered much high-efficient photocatalytic H2O2 generation. Particularly, the sonoZnIn2S4 presented H2O2 production rate of 21295.5 µmol∙g-1∙h-1 in water/benzylalcohol system, which is 3.0 times that of ZnIn2S4 prepared by solvothermal method. The remarkably improved photocatalytic performance of sonoZnIn2S4 might be due to the multiple defects and fast electron-hole pair separation caused by ultrasound cavitation effect. Other metal sulfide photocatalysts with high performance were efficiently fabricated by facile sonochemical technology as well. The sonochemical method realized the rapid preparation of metal sulfide photocatalysts and efficient production of H2O2, which benefits to meet the United Nations Sustainable Development Goals (SDGs) including SDG-7 and SDG-12.

Design strategies of covalent organic framework-based electrodes for supercapacitor application.

Supercapacitors (SCs) have been recognized as a promising electrochemical energy storage (EES) device, thanks to their high-power density, long lifespan, fast charge-discharge capability, and eco-friendliness. The breakthrough of electrode materials that determine the electrochemical performance of SCs is urgently desired. Covalent organic frameworks (COFs), an emerging and burgeoning class of crystalline porous polymeric materials, have been found to have huge potential for application in EES devices by virtue of their unique properties including atomically adjustable structures, robust and tunable skeletons, well-defined and open channels, high surface areas, etc. In this feature article, we aim at summarizing the design strategies of COF-based electrode materials for SCs based on the representative advances. The current challenges and future perspectives of COFs for SC application are highlighted as well.

Cage-Confinement Induced Emission Enhancement.

As a proof-of-concept study, Imi-cage and Phos-cage organic molecular cages (OMCs) containing the triphenylphosphine (TPP) moiety, a nonclassic AIE luminogen (AIEgen), have been designed to demonstrate the cage-confinement induced emission enhancement (CCIEE). Thanks to the confinement effect of OMCs, the rigid Imi-cage exhibits much higher photoluminescence (PL) quantum yield (ΦPL) than the open-shell Semicage and small molecule TPP in both solution and amorphous solid states. The emission of Phos-cage could be further enhanced in crystalline solid state with a remarkably high ΦPL of 97.6% (vs 3.47% of crystalline TPP) benefiting from AIE enabled by the highly ordered molecular packing. The novel strategy of CCIEE via confining an AIEgen into an OMC to achieve a significant emission enhancement will shed light on the development of solid-state highly fluorescent materials. The fluorescent nature of Imi-cage was further exploited for the ultrahighly sensitive detection of the explosive picric acid.

A nanostructured covalent organic framework with readily accessible triphenylstibine moieties for high-performance supercapacitors.

A pristine, redox-active triphenylstibine based COF (Sb-COF) exhibits well-uniform nanostructures which could provide sufficient electron conduction pathways and minimize the ion transport lengths, making triphenylstibine moieties readily accessible by the electrolyte. The assembled Sb-COF//rGO thus provides an excellent energy density of 69 W h Kg-1.

Controlled Synthesis of Palladium Nanoparticles with Size-Dependent Catalytic Activities Enabled by Organic Molecular Cages.

Particle size plays a key role in the performance of metal nanoparticles (MNPs). However, the size-controlled synthesis of MNPs still represents a challenging task. In this work, we revealed a strong solvent effect on the growth of palladium nanoparticles (PdNPs), which was directed by a porous [2 + 3] organic molecular cage (OMC, Phos-cage) containing triphenylphosphine moieties. PdNPs with different average diameters of 0.8, 1.2, and 3.3 nm supported by Phos-cage were obtained by simply varying the reaction media. The catalytic performance of such ultrafine PdNPs in the reduction of p-nitrophenol and a Suzuki-Miyaura coupling reaction has been studied, which clearly shows size-dependent catalytic activity and stability. The knowledge gained in this study, controlling the size of PdNPs supported by the OMC template in different solvents, will open new possibilities for size-controlled synthesis of ultrafine MNPs with high catalytic activity and stability.

Phosphine-Based Covalent Organic Framework for the Controlled Synthesis of Broad-Scope Ultrafine Nanoparticles.

In this work, a phosphine-based covalent organic framework (Phos-COF-1) is successfully synthesized and employed as a template for the confined growth of broad-scope nanoparticles (NPs). Ascribed to the ordered distribution of phosphine coordination sites in the well-defined pores, various stable and well-dispersed ultrafine metal NPs including Pd, Pt, Au, and bimetallic PdAuNPs with narrow size distributions are successfully prepared as determined by transmission electron microscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, and powder X-ray diffraction analyses. It is also demonstrated that the as-prepared Phos-COF-1-supported ultrafine NPs exhibit excellent catalytic activities and recyclability toward the Suzuki-Miyaura coupling reaction, reduction of nitro-phenol and 1-bromo-4-nitrobenzene, and even tandem coupling and reduction of p-nitroiodobenzene. This work will open many new possibilities for preparing COF-supported ultrafine NPs with good dispersity and stability for a broad range of applications.