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BiVO4@PDMS@MS is a floatable photocatalytic system with many microreactors, forming a 3D sandwich-type triphase interface to transfer nitrogen and water simultaneously, enhance light utilization, and achieve excellent nitrogen fixation performance.

We constructed a biosensor for detecting E. coli using a 3D graphene aerogel as the detection substrate. The detection limit of E. coli can be as low as 10 cfu mL−1.

The Ag3PO4 NPs had a high photocatalytic activity in MB degradation under visible-light illumination. The photocatalytic activity reduced by 4.4% after 5 cycles.

Conjugated polymer dots or semiconducting polymer nanoparticles (Pdots) are nanoparticles prepared based on organic polymers. Pdots have the advantages of lower cost, a simple preparation process, good biocompatibility, excellent stability, and easy modification and regulation. Based on these characteristics, they can not only realize super-resolution imaging of subcellular structure, and the localization of deep tissue lesions, but also interact with various substrates to realize quantitative sensing. Besides the imaging and sensing application, these Pdots can also be used as a targeted therapeutic effective agent to achieve several biotherapy functions. In this review, we will focus on the applications of conjugated polymer dots, including related design and preparation strategies, as well as the current situation and future development of specific applications such as imaging and treatment.

Recently, polymer dots (Pdots) possessing conjugated structures have attracted the attention of researchers for use as photocatalysts for H2 evolution reactions. Herein, soluble Pdots (ca. 30 nm) based on the semiconducting polymer poly(9,9-dioctylfluorene) (PFO) were introduced as a photocatalyst for photodegradation activity and light-driven hydrogen generation by a nanoprecipitation method. A photodegradation activity study of these Pdots (PFO-Pdots) with methylene blue (MB) showed a good ability to degrade MB in aqueous solution under simulated light. Moreover, the PFO-Pdots exhibited a good H2 production rate up to 1.20 ± 0.04 mmol h−1 g−1 without platinum or rhodium as a cocatalyst. According to the I–V curves and transient photocurrent response study, it was obvious that a significant photocurrent of the PFO-Pdots was generated under light irradiation. The low recombination rate of the photogenerated carriers and shortened charge diffusion path led to a good photocatalytic H2 evolution rate. These phenomena suggested that the conjugated Pdots only composed of C, H, and O elements had good photocatalytic activity, and it was a powerful supplement to existing polymer photocatalytic systems. Moreover, PFO-Pdots had better photocatalytic activity in water than pure PFO. This study shows that PFO-Pdots or conjugated Pdots may be promising candidates in the field of photocatalysis in the future.

A new battle line is drawn where antibiotic misuse and mismanagement have made treatment of bacterial infection a thorny issue. It is highly desirable to develop active antibacterial materials for bacterial control and destruction without drug resistance. A large amount of effort has been devoted to transition metal oxide and chalcogenide (TMO&C) nanomaterials as possible candidates owing to their unconventional physiochemical, electronic and optical properties and feasibility of functional architecture assembly. This review expounds multiple TMO&C-based strategies to combat pathogens, opening up new possibilities for the design of simple, yet highly effective systems that are crucial for antimicrobial treatment. A special emphasis is placed on the multiple mechanisms of these nanoagents, including mechanical rupture, photocatalytic/photothermal activity, Fenton-type reaction, nanozyme-assisted effect, released metal ions and the synergistic action of TMO&C in combination with other antibacterial agents. The applications of TMO&C nanomaterials mostly in air/water purification and wound healing along with their bactericidal activities and mechanisms are also described. Finally, the contemporary challenges and trends in the development of TMO&C-based antibacterial strategies are proposed.

Er3+ (10%) and Yb3+/Er3+ (10%/10%) doped tetragonal LiLuF4 microcrystals were synthesized via a hydrothermal method. The upconversion (UC) luminescence of LiLuF4:Yb3+,Er3+ and LiLuF4:Er3+ microcrystals is studied under 1560 nm pulsed laser excitation. The UC luminescence spectra indicated that LiLuF4 with doped rare earth ions achieved emissions that come from 2–4 photon UC processes. In the Yb3+/Er3+ doped LiLuF4, the UC fluorescence shows enhanced emission of Er3+ ions in the infrared range of about 1 μm under 1560 nm laser excitation. The UC population processes of Er3+ and the energy transfer (ET) mechanism between Er3+ and Yb3+ played important roles in the as-prepared samples.

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A bio-inspired graphene honeycomb structure was fabricated via the breath figure method using a graphene composite (GO/DODA). The graphene composite was prepared via the phase-transfer method using dimethyldioctadecylammonium (DODA) as the surfactant. The biomimetic structure of the graphene porous film was characterized using optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy. After reducing the GO/DODA porous film to a rGO/DODA porous film, the cell growth on the honeycomb structure was investigated using two cell lines, HeLa cell and human breast cancer cell (MCF-7) lines. In vitro cell experiments showed that the bio-inspired graphene porous film showed no obvious toxicity to HeLa cells or MCF-7 cells and was promising for biomedical applications.

Photocatalytic H2 generation was studied for a series of ZnO/Zn(OH)2 macrostructure photocatalysts. Different ZnO/Zn(OH)2 macrostructures were prepared through a one-step hydrothermal method by adjusting the pH values of the solution and the concentration of dodecyl sulfate. Three different morphologies of the ZnO/Zn(OH)2 macrostructure were synthesized and studied using SEM and XRD. The reflectance spectra revealed that the cone shaped ZnO/Zn(OH)2 macrostructure (ZnO-C) had the lowest reflectivity of UV light. It was found that the photoelectronic properties depend on the morphology of the ZnO/Zn(OH)2 macrostructures. The photocatalytic activity of these ZnO/Zn(OH)2 macrostructure hybrids (about 0.070 mmol g−1 h−1) were higher than that observed for ZnO nanorods (0.050 mmol g−1 h−1). These results suggest the substantial potential of metal oxide materials with macrostructures in photocatalytic water splitting applications.

The fabrication of photocatalysts to achieve efficient utilization of renewable solar energy has attracted broad interest. Herein, a plasmonic spiky TiO2/Au nanorod (NR) nanohybrid was prepared by in situ nucleation and growth of spiky TiO2 in AuNR colloidal solution. The spiky TiO2/AuNR nanohybrids demonstrated enhanced hydrogen evolution activity and photocurrent generation under both visible light and simulated solar light irradiation as compared to bare spiky TiO2 nanoparticles and commercial TiO2. Specifically, the spiky nanohybrids displayed a high H2 production rate of 1.81 mmol g−1 h−1 under simulated solar light irradiation, which is 1.7 times higher than that of TiO2/Au nanosphere nanohybrids, and remain stable for three cycles. The improved photocatalytic H2 evolution demonstrated by the nanohybrids can be ascribed to the coupling effect of the AuNRs and the unique spiky structure. Furthermore, the charge transfer process during H2 evolution was investigated by photocurrent and electrochemical impendence spectroscopy (EIS) measurements. A fast and stable photocurrent was observed for the spiky TiO2/AuNR nanohybrid photoelectrode under both visible light and simulated solar light irradiation, while the EIS plots indicate a rapid charge transfer within the nanohybrids. Such a nanohybrid with a bio-inspired structure will afford new insights for the fabrication of novel photocatalysts.

A facile approach for the preparation of Au nanorod/ZnO nanodisks (AuNR/ZnONDKs) through in situ nucleation and growth of ZnO in AuNR colloidal solution was developed. This is the first report of AuNRs modified on the ZnO surface. Furthermore, the aspect ratios of AuNRs in nanohybrids of AuNR/ZnONDKs were also tuned to achieve tunable and broad LSPR bands for an optimized photocatalytic performance. All of the resultant AuNR/ZnONDK nanohybrids with exposed AuNRs exhibit much higher photocatalytic activity and photocurrent generation compared to commercial ZnO (C-ZnO). In particular, AuNR-707/ZnONDKs express a swift and steady photocurrent of 0.33 mA cm−2, which is 16.5 times higher than the photocurrent generated by C-ZnO. The facile approach presented here opens up a new avenue for the rational design and preparation of high-performance photocatalysts for the future applications in both environmental purification and photoelectric conversion.

Transformation from single-mesoporous to dual-mesoporous structured organosilica nanoparticles can be achieved by simply varying the volume fraction of ethanol in the synthesis system, using lauryl sulfonate betaine and sodium dodecyl sulfonate as dual-templates. Core-shell structured dual-mesoporous organosilica nanoparticles possess smaller mesopores (4.0 nm) in the shell and flower-like larger mesopores (46 nm) in the core. Owing to the unique mesostructure, dual-mesoporous organosilica nanoparticles show a high loading capacity and a slow release rate for cargo molecules. The large mesopores on the inside can provide a large storage space for the guest molecules and the small mesopores in the outer shell act as a natural valve, slowing the release. In addition, both single-mesoporous and dual-mesoporous organosilica nanoparticles, exhibit low cell toxicity and excellent cell permeability.

A facile float zone method to grow ZnO microrods with a hexagonal crystal structure is described. It was found that the crystal-growth mechanism was different from the well-known vapor–liquid–solid (VLS) growth mechanism. However, the one-dimensional growth morphologies occurring in the vapor phase are similar to those of ZnO grown using conventional VLS processes. The free-exciton, bound-exciton, acceptor-exciton, two-electron satellite emission, and their phonon replicas, obtained from the 15 K photoluminescence (PL) spectra of the ZnO microrods, were recorded. The PL spectra of the ZnO microrods at temperatures between 15 and 150 K show that the bound-exciton peak dissociates into a free-exciton peak and that the free-exciton emission and its phonon replicas dominate at temperatures above 120 K. Following the approach of Viswanath for measuring the intensity ratio of PL peaks, we found that the strongest bound-exciton peak at 3.3615 eV had a thermal activation energy of 15.9 meV, consistent with the value expected for the exciton-defect binding energy. This bound-exciton peak was not observed at temperatures above 120 K.

Self-assembling inorganic nanoparticles (NPs) into macroscopic three dimensional (3D) architectures often requires the assistance of organic components, leaving residual organics in the resultant. In this work, organic-free MnO2 aerogels with ultralow density have been achieved by the self-assembly of two dimensional (2D) MnO2 nanosheets via an ice-templating approach. To the authors' best knowledge, it is the first reported case of constructing a high-purity inorganic aerogel from preformed NPs without using any functionalization or stabilization agents. Moreover, it has been demonstrated that an ultralight MnO2 aerogel with a density as low as ∼0.53 mg cm-3, which is the lightest metal oxide aerogel to date, can be well obtained by such an approach. The successful formation of the aerogel can be attributed to the enhanced van der Waals force between the 2D building blocks that have been more orderly arranged by the squeezing of ice crystals during the freezing process. Hence, this work shows a pioneering example of assembling inorganic NPs into aerogels relying only on the weak interactions between NPs (e.g. van der Waals forces). It has also been demonstrated that the obtained MnO2 aerogel can function as an effective absorbent for toxic reducing gas, owing to its strong oxidation ability and high porosity. The strategy presented herein holds good potential to be applied to the fabrication of other high-purity inorganic aerogels, especially those with 2D building blocks readily available.

The most common materials used to generate near-infrared-driven photocatalysis occur by 980 nm laser excitation of composites that are a combination of a semiconductor and upconverting luminescence particles. The challenge remains to increase the light harvesting efficiency, and thus, it is necessary to extend the absorption spectra of photocatalysts. In this work, NaYF4:Yb,Er/CdSe composites were prepared by depositing CdSe nanocrystals onto the surface of NaYF4:Yb,Er microcrystals. UV and visible emission of light resulted from multiphoton upconverting processes in Er3+ under 1560 nm laser irradiation, which, in turn, activated the CdSe catalyst. The energy transfer between NaYF4:Yb,Er and CdSe was investigated by steady-state and dynamic fluorescence spectroscopy. The photocatalytic performance was investigated by the degradation of methylene blue in aqueous solution. These results show that Er coupled with semiconductor heterojunctions provides a photocatalyst that operates in the extended near-infrared range.

A bio-inspired photoelectrode was developed by self-assembly of honeycomb graphene oxide films, followed by reduction and in situ growth of ZnO nanorods (NRs). In the nanocomposite film, the graphene substrate shows an elegant macroporous structure of an ordered honeycomb pattern, with uniformly and densely deposited ZnO NRs. In a photoelectric conversion system, the rGO/DODA/ZnO honeycomb film not only significantly improves light-capturing ability, but also provides a direct and stable pathway for rapid electron transport, promoting photoinduced electron–hole separation. Compared to the counterpart of a smooth hybrid film, the honeycomb composite material shows a decreased incident light reflection of 26%, and a three-fold increase in photocurrent. It is envisioned that this facile and scalable fabrication approach, as well as this bio-inspired structure, will open a new avenue for the rational design and engineering of high-performance solar energy conversion devices.

Semiconductor polymer dots (Pdots) were encapsulated into a SiO2 matrix to form fluorescent nanocomposites using a modified Stober method. Significantly, the photostability and thermal stability of the nanocomposites were greatly improved as compared to those of pure Pdots. The luminescent nanocomposites combined with blue LEDs result in white-light emitting devices with a high color-rendering index.

3D protonated titanate nanoflowers synthesized by an organic-free and cost-effective facile method exhibit a high reversible capacity, excellent cycling performance, and a remarkable rate capability when they worked as anode electrode materials for lithium-ion batteries.