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A novel and convenient method for fabricating homogeneous nanocatalysts with high catalytic activity and controllable reusability is promising for catalytic reduction. In this study, a high-efficiency magnetic recyclable nanocatalyst (PFe3O4@CD@PdNPs) was successfully prepared via depositing highly dispersed palladium nanoparticles (Pd NPs) on a thermo-responsive copolymer support functionalized with superparamagnetic Fe3O4 nanoparticles (NPs) with carbon dots (CDs) as both a stabilizing and reducing agent. The thermo-responsive copolymers with catechol end groups could be facilely anchored onto Fe3O4 NPs (PFe3O4) through a mussel-inspired chemistry strategy. The well-dispersed ultrafine Pd NPs were located on Fe3O4 NPs decorated with copolymer brushes using an episulfide ligand-containing copolymer as a costabilizer. Fourier transform infrared spectroscopy, thermogravimetric analysis and other tests proved that the copolymer brushes were successfully grafted on the surface of the Fe3O4 NPs. Moreover, transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the presence of CDs in the nanohybrids. In addition, the PFe3O4@CD@PdNPs showed interesting thermo-responsive catalytic behaviour because of the presence of thermo-responsive polymer chains on the catalyst surface. Finally, owing to good water dispersibility and the synergistic effect of the Pd NPs with CDs, the PFe3O4@CD@PdNP nanocatalyst possessed higher catalytic activity for the catalytic reduction of different dyes and nitrophenols compared with PdNP@PFe3O4 without CD modification.

In this work, catechol-formaldehyde resin (CFR) microspheres were successfully prepared by a solvothermal method under alkaline conditions. Furthermore, the impacts of the concentration, solvent ratio and temperature on the size and morphology of the as-synthesized CFR microspheres were studied in detail. The results showed that the size of the CFR microspheres could be controlled between 50 and 800 nm by changing the reaction conditions, and the morphology of the CFR microspheres was significantly different under different conditions. The as-prepared CFR microsphere as a support was also used to construct a CFR-stabilized Ag nanoparticle (CFR@Ag) nanohybrid via an in situ reduction and growth process on mussel-inspired CFR layers. Upon alkaline solution treatment on the CFR microspheres, silver nanoparticles could be deposited onto the surface or inside of the CFR microspheres. Additionally, the abundant hydroxyl groups on the CFR spheres could act as reducing agents for both the Ag+ precursor and ligands to stabilize Ag NPs without additional reducing agents. The as-prepared CFR@Ag and alkali-treated CFR microsphere stabilized Ag NP (TCFR@Ag) nanohybrids could serve as highly efficient nanocatalysts for the reduction of 4-nitrophenol and methylene blue (MB) dye with good cycling stability. In addition, the nanohybrids as outstanding antibacterial agents also showed long-term inhibition of microbial growth against bacteria Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).

Magnetic Fe3O4@catechol–formaldehyde resin (CFR) core–shell nanospheres were fabricated via a controllable hydrothermal method. The shell thickness of Fe3O4@CFR nanospheres can be effectively regulated in the range of 10–170 nm via adjusting reaction parameters. In particular, catechol groups on the surface of nanospheres also play a significant role in mussel-inspired chemistry to further combine with graphene oxide (GO) to wrap the Fe3O4@CFR spheres. The obtained Fe3O4@CFR and Fe3O4@CFR@GO nanospheres can be used as the effective catalyst supports of small Pd nanoparticles (PdNPs

A series of novel well-defined 8-hydroxyquinoline (HQ)-containing thermoresponsive amphiphilic diblock copolymers {poly(styrene-co-5-(2-methacryloylethyloxy-methyl)-8-quinolinol)-b-poly(N-isopropylacrylamide) P(St-co-MQ)-b-PNIPAm (P1,2), P(NIPAm-co-MQ)-b-PSt (P3,4)} and triblock copolymer poly(N-isopropylacrylamide)-b-poly(methyl-methacrylate-co-5-(2-methacryloylethyloxymethyl)-8-quinolinol)-b-polystyrene PNIPAm-b-P(MMA-co-MQ)-b-PSt (P5) were prepared by reversible addition–fragmentation chain-transfer (RAFT) polymerization, and their self-assembly behaviors were studied. Block copolymer P1–P5-stabilized gold nanoparticles (Au@P1–Au@P5) with a small size and a narrow distribution were obtained through the in situ reduction of gold precursors in an aqueous solution of polymer micelles with HQ as the coordination groups. The resulting Au@P nanohybrids possessed excellent catalytic activity for the reduction of nitrophenols using NaBH4. The size, morphology, and surface chemistry of Au NPs could be controlle...

Novel temperature-responsive block copolymer-functionalized graphene oxide (GO) nanosheets were successfully prepared via non-covalent π–π stacking interactions between GO and pyrene-terminated PNIPAM-b-P(OEGMA-co-MQ). The pyrene-terminated block copolymer was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization using a pyrene functional RAFT agent and the monomers N-isopropylacrylamide (NIPAM), oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA) and 5-(2-methacryloyl-ethyloxymethyl)-8-quinolinol (MQ). ZnS nanoparticles were also integrated into the block copolymer-decorated GO via the coordination of MQ units of the block copolymers to fabricate a fluorescent nanocomposite with good temperature-responsive behavior based on a conformation change in the PNIPAM blocks on the GO sheets. The as-prepared block copolymer anchored graphene oxide@ZnS NPs nanocomposite can be used as a fluorescent sensing platform for sensitive and selective detection of nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) with a detection limit of 4.4 nM via a fluorescence resonance energy transfer (FRET) process.

A novel strategy was developed to fabricate thermo-responsive copolymer functionalized reduced graphene oxide@Fe3O4@Au magnetic nanocomposites (Au NPs@GFDP) for highly efficient catalysis. Superparamagnetic Fe3O4 nanoparticles (NPs) on reduced graphene oxide (RGO@Fe3O4) were obtained via a one-pot chemical functionalization method. RGO@Fe3O4 was coated with dopamine (DA) to generate polydopamine (PDA) modified RGO@Fe3O4 (GFD) through a combination of mussel inspired chemistry of dopamine in a weakly alkaline aqueous solution. The thermo-responsive polymer of poly(N-isopropylacrylamide-co-2,3-epithiopropyl methacrylate) P(NIPAM-co-ETMA) (P) was synthesized via a reversible addition fragmentation chain transfer (RAFT) polymerization and was facilely grafted onto the surface of GFD through a Michael addition reaction. The final gold nanoparticle (Au NP) functionalized GFDP nanocomposites were obtained through in situ reduction of gold precursors in GFDP solution using the episulfide groups of P(NIPAM-co-ETMA) as a ligand. The Au NPs@GFDP nanocomposite exhibited excellent dispersibility and stability in aqueous solutions. More importantly, the obtained nanocomposite also displayed easy recyclability because of the existence of Fe3O4 NPs and a higher catalytic efficiency for the reduction of nitrophenols over the Au NPs@RGO@Fe3O4 and Au NPs@GO without polymer modification. Au NPs@GFDP modified with PNIPAM also exhibited excellent temperature-responsive behavior for the catalytic reduction of nitrophenol. Therefore, the strategy described in this work may be of great potential for various industrial catalytic applications.

Magnetic Fe

Well-dispersed ultrafine palladium nanoparticles supported by reduced graphene oxide functionalized with catechol-terminated thermo-responsive block copolymer (PdNPs@BPrGO) were successfully constructed for highly efficient heterogeneous catalytic reduction. We first synthesized a novel temperature-responsive episulfide-containing double-hydrophilic diblock copolymer, poly(poly(ethylene glycol) methyl ether methacrylate-co-2,3-epithiopropyl methacrylate)-block-poly(N-isopropylacrylamide) (P(PEGMA-co-ETMA)-b-PNIPAM), through a reversible addition–fragmentation chain transfer (RAFT) polymerization utilizing a chain-transfer agent with a catechol unit as the end group. The obtained block copolymers can be facilely anchored to the surface of GO via mussel-inspired chemistry. The PdNPs were loaded on GO decorated with block copolymer brushes (BPrGO) as a support via the in situ reduction of palladium precursors with the episulfide ligands of the block copolymer as a stabilizer. The resulting PdNPs@BPrGO nanohybrid catalyst had good water dispersibility and stability. Furthermore, a low dosage of PdNPs@BPrGO catalyst exhibited excellent catalytic performance in the reduction of methylene blue and nitrophenols. The performance was attributed to the ability of PdNPs@BPrGO to facilitate the diffusion of reactants compared to PdNPs@GO without polymer modification. PdNPs@BPrGO also possessed an interesting temperature-responsive catalytic property due to the reversible “coil-to-globule” phase transition behaviour of PNIPAM blocks onto the surface of catalyst. The PdNPs@BPrGO catalyst was successfully recovered and reused five times without any detectible loss in catalytic activity, demonstrating its great potential in a wide range of industrial catalytic applications.

We report discrete heterojunction small molecular organic photovoltaics (OPVs) with enhanced performance by modifying the interface using molybdenum oxide (MoO x ) and molecular template layer perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA). A large increase in open-circuit voltage was obtained in copper phthalocyanine/fullerene, i . e ., CuPc/C 60 and CuPc/PCBM, discrete planar heterojunction photovoltaics with an insertion of 5 nm MoO x hole transport layer at the interface between the anode electrode and the CuPc donor layer. It results from the band bending at the interface and the pinning of the highest occupied molecular orbital level of CuPc to the Fermi level of MoO x due to the defect states (oxygen vacancies) in MoO x thin films. Moreover, the short-circuit current showed an efficient improvement by inserting a 1 nm PTCDA layer at the interface between the MoO x layer and the CuPc layer. The PTCDA layer induces the growth of CuPc thin film with lying-down molecular arrangement, supporting the charge transports along the vertical direction. The power conversion efficiencies of CuPc/C 60 and CuPc/PCBM discrete planar heterojunction photovoltaic devices were improved from about 0.80% to 1.50% with inserting both MoO x and PTCDA layers. The results suggest that the performance of organic discrete planar heterojunction photovoltaics could be optimized by interface modification with combining hole transport layer and molecular template layer, which are potentially suitable for other highly efficient OPVs, such as small molecular tandem OPVs.

TiO2 sols synthesized with a facile solution-based method were used as a buffer layer between the active layer and the cathode Al in conventional structure polymer solar cells (PSCs). Using transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD) and atomic force microscopy (AFM), the morphological and crystallographic properties of synthesized TiO2 nanoparticles (TiO2 NPs) as well as the buffer layer were studied in detail. It was observed that by increasing H2O in the process of peptization both the crystallinity and particle size of TiO2 NPs were enhanced, while the particles in sol showed a narrower size distribution conformed by dynamic light scattering. Inserting TiO2 NPs as a buffer layer in conventional structure PSCs, both the power conversion efficiency (PCE) and stability were improved dramatically. PSCs based on the structure of ITO/PEDOT:PSS/P3HT:PCBM/TiO2 NPs/Al showed the short-circuit current (Jsc) of 12.83 mA/cm2 and the PCE of 4.24%, which were improved by 31% and 37%, respectively comparing with the reference devices without a TiO2 buffer layer. The stability measurement showed that PSC devices with a TiO2 NPs buffer layer could retain 80% of the original PCEs after exposed in air for 200 h, much better than the devices without such a buffer layer. The effect can be attributed to the protection by the buffer layer against oxygen and H2O diffusion into the active layers. The observations indicate that TiO2 NPs synthesized by facile solution-based method have great potential applications in PSCs, especially for large-area printed PSCs.

Ordered nanocolumn-array phthalocynine semiconductor thin films with controllable molecular orientation were fabricated by combining molecular template growth (MTG) and glancing angle deposition (GLAD) techniques. The pre-deposited planar perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) molecular template layer induces phthalocynine molecules arrange with a lying-down molecular orientation, in which the π–π stacking is vertical to the substrate improving the charge transport along the vertical direction; While the GLAD technique supports the formation of nanocolumn-array thin films, supplying a much larger exposed surface area than the conventional compact thin films. The ordered nanocolumn-array thin films with controllable molecular orientation fabricated by combining MTG and GLAD techniques show the potentials to fabricate ordered bulk heterojunction for improving the performance in organic photovoltaics.