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Fluorosis has been regarded as a worldwide disease that seriously diminishes the quality of life through skeletal embrittlement and hepatic damage. Effective detection and removal of fluorinated chemical species such as fluoride ions (F-) and perfluorooctanoic acid (PFOA) from drinking water are of great importance for the sake of human health. Aiming to develop water-stable, highly selective and sensitive fluorine sensors, we have designed a new luminescent MOF In(tcpp) using a chromophore ligand 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (H4tcpp). In(tcpp) exhibits high sensitivity and selectivity for turn-on detection of F- and turn-off detection of PFOA with a detection limit of 1.3 μg L-1 and 19 μg L-1, respectively. In(tcpp) also shows high recyclability and can be reused multiple times for F- detection. The mechanisms of interaction between In(tcpp) and the analytes are investigated by several experiments and DFT calculations. These studies reveal insightful information concerning the nature of F- and PFOA binding within the MOF structure. In addition, In(tcpp) also acts as an efficient adsorbent for the removal of F- (36.7 mg g-1) and PFOA (980.0 mg g-1). It is the first material that is not only capable of switchable sensing of F- and PFOA but also competent for removing the pollutants via different functional groups.

A new type of hybrid material (NCMTs@MoO2/FeNi3) with a multi-layer heterostructure was designed and fabricated via a one-step pyrolysis process using FeOOH/NiMoO4@PDA as the precursor. FeOOH/NiMoO4@PDA was prepared by the solvothermal method, followed by the nickel-ion etching method coupled with the polymerization of dopamine (DA). The as-obtained material was made of nitrogen-doped carbon nanotubes embedded with FeNi3 and MoO2 nanoparticles (NPs). Notably, the FeNi3 NPs exhibited significantly improved performance in the reduction of 4-nitrophenol (4-NP) and adsorption of histidine-rich protein as well as provided appropriate magnetism resources. The MoO2 NPs imparted a metallic nature with excellent conductivity, and the N-doped mesoporous carbon microtubes also improved conductivity and facilitated mass transfer, thus leading to enhanced performance in catalysis. Benefiting from the 1D hierarchical porous structure and compositional features, the NCMTs@MoO2/FeNi3 composites exhibited excellent performance in 4-NP reduction and protein adsorption via specific metal affinity between the polyhistidine groups of proteins and the FeNi3 NPs. The result presented here indicates that the strategy of combining tailored components, heterostructuring, and carbon integration is a promising way to obtain high-performance composites for other energy-related applications. [ABSTRACT FROM AUTHOR]

Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) showed great potential for bioimaging due to their integration of non-in situ excitation and deep tissue penetration. However, PLNPs are often introduced with Cr3+ ions as the NIR emission centers. Herein, we report Cr-free Bi2Ga3.985O9:1.5% Fe3+ (BGF), with Fe3+ ions as the NIR emission centers. BGF under 310 nm excitation exhibited NIR afterglow emission at 794 nm in the first biological imaging window (650–950 nm), with the afterglow duration of 3 h. BGF was grafted with hydroxyl groups and then polydopamine (PDA) for the integration of indocyanine green (ICG) through π–π stacking and hydrophobic interactions, as the PLNP–PDA–ICG composite. Bi in the composite, as a heavy atom element, exhibits computed tomography (CT) contrast capacity, while PDA is a photothermal agent, and ICG is excited to produce reactive oxide species for photodynamic therapy. The afterglow/CT dual-modality imaging-guided photothermal/photodynamic combination therapy was validated with in vitro/vivo imaging and therapeutic applications. This work provides the Cr-free PLNP composite for drug-free theranostics with a low toxicity. [ABSTRACT FROM AUTHOR]

Tubular structured composites have attracted great interest in catalysis research owing to their void-confinement effects. In this work, we synthesized a pair of hollow N-doped carbon microtubes (NCMTs) with Fe3O4 nanoparticles (NPs) encapsulated inside NCMTs (Fe3O4@NCMTs) and supported outside NCMTs (NCMTs@Fe3O4) while keeping other structural features the same. The impact of structural effects on the catalytic activities was investigated by comparing a pair of hollow-structured nanocomposites. It was found that the Fe3O4@NCMTs possessed a higher peroxidase-like activity when compared with NCMTs@Fe3O4, demonstrating structural superiority of Fe3O4@NCMTs. Based on the excellent peroxidase-like catalytic activity and stability of Fe3O4@NCMTs, an ultra-sensitive colorimetric method was developed for the detection of H2O2 and GSH with detection limits of 0.15 μM and 0.49 μM, respectively, which has potential application value in biological sciences and biotechnology. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF)-derived hollow Co3O4 has attracted considerable attention owing to its porosity, high dispersion and large specific surface area. To further improve its activity, well-dispersed Co3O4-decorated MnO2 was successfully fabricated using MnO2@ZIF-67 as the precursor. Initially, MnO2 nanowires were prepared, which acted as a structure-directing support for the growth of ZIF-67. Polyvinylpyrrolidone (PVP) was exploited as a surface stabilizer, growth modifier and dispersant. After calcination, the one-dimensional shish-kebab MnO2@Co3O4 composite was obtained. Subsequently, its oxidase-mimicking performance was validated using 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrate. This composite possessed abundant active sites, continuously ordered hetero-interface, and increased diffusion pathway, and thereby high oxidase-mimicking activity, which was 2 times higher than that of MnO2 and 14.6 times higher than that of Co3O4. The mechanism studies revealed that MnO2@Co3O4 enhanced the O2 adsorption ability and facilitated the production of O2˙− radicals, resulting in improved activity. Considering the selective inhibition of L -cysteine, a sensitive and selective assay for the detection of L -cysteine was established. This work presents an effective strategy for designing new types of hybrid materials with potential prospect in the fields of bioanalysis, catalysis, and environmental monitoring. [ABSTRACT FROM AUTHOR]

Herein, we designed and prepared the persistent luminescence nanoparticles (PLNPs) of γ-Ga2O3:Cr,Ba rationally with Cr ions to achieve the near-infrared (NIR) emission at 700 nm and Ba ions to improve the emission intensity by inducing trap distribution. Energy transfer between γ-Ga2O3 and Cr ions occurs as the emission at 508 nm decreases and that at 700 nm increases along with the increased content of Cr ions. In combination with the trap depth, band gap of the host, and energy levels of Cr ions, an emission mechanism was proposed. Thus, NIR emission (700 nm), high brightness, large Stokes shift (446 nm), and long afterglow time (90 min) were achieved with the optimal γ-Ga2O3:0.0025Cr,0.0012Ba (γGCB) under excitation at 254 nm. The emission intensity of γGCB is temperature-dependent for non-contact ratiometric temperature sensing, and temperature linearity ranging from 300 to 420 K was achieved with an absolute sensitivity of 3.4% K−1. γGCB and γ-G2O3 are white under sunlight but exhibit red and green emissions under single excitation at 254 nm. Thus, Morse and binary codes are adapted to achieve encryption information transfer with the combination of γGCB and γ-G2O3. This work provides ideas for selecting a host, emission center, and trap for PLNPs with desirable properties and thus achieves extensive applications, as validated with ratiometric temperature sensing and encryption information transfer. [ABSTRACT FROM AUTHOR]

Hydrophobic conjugated polymers have poor ionic transport property, so hydrophilic side chains are often grafted for their application as organic electrochemical transistors (OECTs). However, this modification lowers their charge transport ability. Here, an ionic gel interfacial layer is applied to improve the ionic transport while retaining the charge transport ability of the polymers. By using the ionic gels comprising gel matrix and ionic liquids as the interfacial layers, the hydrophobic polymer achieves the OECT feature with high transconductance, low threshold voltage, high current on/off ratio, short switching time, and high operational stability. The working mechanism is also revealed. Moreover, the OECT performance can be tuned by varying the types and ratios of ionic gels. With the proposed ionic gel strategy, OECTs can be effectively realized with hydrophobic conjugated polymers. [ABSTRACT FROM AUTHOR]

Anchoring bimetallic alloys in a one-dimensional(1D) heteroatom-doped carbon matrix with excellent electro-conductibility is a powerful strategy for the reduction of 4-nitrophenol (4-NP). Herein, we report the design and fabrication of CoNi bimetallic nanoparticles (NPs) decorated on N, P, and S-doped carbon/MnO nanowires (NWs) as an active catalyst for the reduction of 4-NP. The CoNi bimetallic NPs enable the full utilization of accessible edge sites, and the unique 1D framework creates a large surface area, exposing abundant active sites and providing a fast charge/ionic diffusion pathway. Moreover, the synergistic electronic interaction between the CoNi NPs and N, P and S co-doped carbon layer leads to optimal electronic structures and good adhesion ability, thus facilitating the catalytic performance. As a result, the obtained CoNi decorated on N, P, and S-doped carbon/MnO NWs exhibited superior catalytic activities in the reduction of 4-NP as well as robust stability in catalyst recycling. This work highlights the effect of rationally constructing a 1D bimetallic catalyst. [ABSTRACT FROM AUTHOR]