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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.

Herein, the CaTiO3/Cu/TiO2 all-solid-state Z-scheme heterojunction is successfully designed via Cu nanoparticles situating at the interface between CaTiO3 and TiO2 with a new synthesis route. Interestingly, TiO2 nanosheets are generated in-situ on the surface of CaTiO3 in the second step hydrothermal reaction. The lifetimes of photoexcited carriers, photoluminescence emission spectra and transient photocurrent response tests have confirmed that the efficient Z-scheme charge transmission path of the CaTiO3/Cu/TiO2 is beneficial to facilitate the separation of photogenerated carriers and reduce their recombination efficiency. As expected, the hydrogen generation rate of CaTiO3/Cu/TiO2 is increased to 23.550 mmol g-1h−1 with the appropriate amount of copper loading, which is about 981 times and 93 times higher than that of pristine CaTiO3 (0.024 mmol g-1h−1) and CaTiO3/TiO2 (0.253 mmol g-1h−1), respectively. Furthermore, the CaTiO3/Cu/TiO2 sample shows good stability in cycle experiments. Particularly, experimental results show that the non-noble metal Cu nanoparticles can be an effective electron mediator. And these merits strongly demonstrate that the CaTiO3/Cu/TiO2 composites have potential application in photocatalytic field. This study can provide fundamental guidance for designing rationally efficient non-noble metal vector Z-scheme system photocatalysts with outstanding photocatalytic H2 generation performance.

Bacterial infection is one of the most frequent wound complications and has become a major public health concern. Increasing resistance to antibiotics has been noted with these agents broadly used in wound management. It is an urgent demand to develop alternative antibacterial strategies with a reduced chance of resistance. Herein, a Nepenthes-mimicking nanosheet array of MoS

Conjugated polymer dots (Pdots) are often used as excellent fluorescent probes in the biomedical field. In the process of preparing Pdots, the rapid change of the solvent polarity will result in a messy and defective stacking of the polymer chains in the particle, and these stacking defects of the polymer chains may weaken its luminescence properties. Here, we try to optimize the stacking of the conjugated polymer chains by the thermal annealing treatment. After the low temperature thermal treatment, the fluorescence intensity of Pdots can be enhanced by about 11%-29%, and Pdots maintain their original stability and biosafety. We used transmission electron microscopy (TEM) and single particle fluorescence imaging to reveal the possible mechanism of the chain stacking optimization process, that is, the thermal annealing process of Pdots is the competition between internal chain rearrangement in the particle and particle aggregation. The luminescence-enhanced Pdots exhibit good cellular imaging performance. These results prove that it is feasible to extend the thermal annealing treatment from planar polymer devices to polymer nanoparticles. It provides the possibility to realize stable and complex biological imaging applications using Pdots with a simple molecular structure, and a mature improvement scheme for the mass preparation of Pdots.

There is a great deal of interest in the development of nanoparticles for biomedicine. The question of how many nanoparticles are taken up by cells is important for biomedical applications. Here, we describe a fluorescence method for the quantitative measurement of the cellular uptake of polymer dots (Pdots) and a further estimation of intracellular Pdots photosensitizer for fluorescence imaging and photodynamic therapy. The approach relies on the high brightness, excellent stability, minimal aggregation quenching, and metalloporphyrin doping properties of the Pdots. We correlated the single-cell fluorescence brightness obtained from fluorescence spectrometry, confocal microscopy, and flow cytometry with the number of endocytosed Pdots, which was validated by inductively coupled plasma mass spectrometry. Our results indicated that, on average, ∼1.3 million Pdots were taken up by single cells that were incubated for 4 h with arginine 8-Pdots (40 μg/mL, ∼20 nm diameter). The absolute number of endocytosed Pdots of individual cells could be estimated from confocal microscopy by comparing the single-cell brightness with the average intensity. Furthermore, we investigated the cell viability as a result of an intracellular Pdots photosensitizer, from which the half maximal inhibitory concentration was determined to be ∼7.2 × 105 Pdots per cell under the light dose of 60 J/cm2. This study provides an effective method for quantifying endocytosed Pdots, which can be extended to investigate the cellular uptake of various conjugated polymer carriers in biomedicine.

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.

Alpha-fetoprotein (AFP) in adult serum often appears in early liver cancer. Therefore, early detection of an abnormal elevation of AFP concentration is important for the early diagnosis and treatment of primary liver cancer. In this work, a photoelectrochemical (PEC) electrode was fabricated for AFP-sensitive detection based on a reduced graphene oxide (rGO) honeycomb structure. After layer-by-layer bioconjugation, the immunoassay graphene electrode was modified with anti-AFP antibodies (Ab). Meanwhile, polymer nanoparticles (PFBT dots) were prepared via a nanoprecipitation method. In addition, the AFP was modified by using the PFBT dots and glucose oxidase (GOD), which formed a fluorescent probe (AFP-PFBT-GOD). By the competitive linkage of AFP and AFP-PFBT-GOD onto the anti-AFP modified honeycomb structure electrode, an immunosensor for AFP detection was obtained. During the PEC test, the electrons produced by the catalytic reaction of glucose and GOD can scavenge the photogenerated holes on the PFBT dots, which can reduce the recombination of photogenerated holes and electrons on the PFBT dots. The PEC immunosensor based on a rGO honeycomb structure exhibited a linear detection range of 0.05–100 ng/mL with a detection limit of 0.05 ng/mL. The excellent detection performance of the graphene PEC biosensor provides an opportunity for the early diagnosis of primary liver cancer.

It still remains a challenge to explore facile, economic, and environmental friendly process for the fabrication of graphene aerogels with low density and high purity to meet the various applications. Herein, arbitrary-shaped reduced graphene oxide (rGO) aerogels are prepared by freeze-drying process and followed unsaturated water vapor reduction method staring from GO aqueous suspensions for the first time. Water vapor hydrothermal treatment can decompose all oxygen-containing functional groups in GO and repair GO surface defects effectivly. At higher temperatures (≥175 °C), the carbon in GO may react with water vapor via water-gas shift reaction to form CO, which could also be used as the reductant for the reduction of GO aerogels. The water volume as well as the temperature are key parameters for realizing high reduction degree as well as good shape control of rGO aerogels. Arbitrary shaped rGO aerogels could be prepared by using various molds for freezing GO suspensions. rGO aerogels exhibit a high oil/water separation performance, which could absorb various oils up to 40-55 times of its initial weight with high recyclability. Moreover, the rGO aerogels exhibit typical pressure sensing behavior and excellent energy storage capacitance, which hold great potential applications in flexible pressure sensors and supercapacitors.

MicroRNAs (miRNAs) are a class of small, noncoding RNAs involved in nearly all genetic central dogma processes and human biological behavior, which also play a significant role in the pathological activity of tumors, such as gene transcription, protein translation, and exosome secretion. Therefore, through the navigation of certain specific miRNAs, we can trace the specific physiological processes or image some specific tissues. Designing and accurately positioning microRNA (miRNA)-sensitive fluorescent nanoprobes with benign specificity and recognition in cells or tissues are a challenging research field. To solve the difficulties, we introduce four semiconducting polymer dots (Pdots) as nanoprobes linked by specific miRNA antisense sequences for monitoring the pathological grading by the variation in miRNA expression. Based on the base pairing principle, these miRNA-sensitive Pdots could bind to specific miRNAs within the cancerous cells. As impacted by the background of different pathology gradings, the proportions of the four hepatocellular carcinoma (HCC)-specific miRNAs within the cancerous cell are different, and the pathological grading of the patient tissues can be determined by comparing the palette combinations. The short single-stranded RNA-functionalized Pdots, which have excellent microRNA sensitivity, are observed in an experimental cell model and a series of tissue specimens from HCC patients for the first time. Using the Förster (or fluorescence) resonance energy transfer (FRET) model of Pdots and Cy3dt tag to simulate in vivo miRNA detection, the superior sensitivity and specificity of these nanoprobes are verified. The interference of subjective factors in traditional single/bis-dye emission intensity detection is abandoned, and multiple label staining is used to enhance sensitivity further and reduce the false-positive rate. The feasibility exhibited by this novel staining method is verified in normal hepatocellular HCC cell lines and 16 frozen ultrathin tissue sections, which are employed to quantify pathological grading-related color presentation systems for clinical doctors and pathologists' use. The intelligently designed miRNA-guided Pdots will emerge as an ideal platform with promising biological imaging.

Monodisperse cubic NaYF4: 20%Yb, 2%Er nanoparticles (NPs) were successfully synthesized using the high-temperature thermal decomposition method. It is found that the crystal structure of NaYF4: 20%Yb, 2%Er, [Formula: see text]%Eu ([Formula: see text] 0, 2, 4) NPs changes from cubic to hexagonal phase with the increase in Eu[Formula: see text] concentration, and the upconversion (UC) luminescent intensities of green and red emissions were decreasing. The emission peaks of Eu[Formula: see text] ([Formula: see text] ([Formula: see text] 1, 2)) ions and the extra peaks of Er[Formula: see text] ([Formula: see text] ions at 450 nm are found, which suggests that the energy transfer between Er[Formula: see text] ions and Eu[Formula: see text] ions occurred with the near infrared light excitation. The probable mechanism related to the cubic-to-hexagonal phase transition of NaYF4 and energy transfer between Eu[Formula: see text] and Er[Formula: see text] ions or Yb[Formula: see text] ions are discussed.

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.

Nowadays, bacterial resistance has continued to be a troublesome issue caused by the abuse of antibiotics, and it is the paramount difficulty in resolving the bacterial proliferation and infection. In this study, fresh lotus leaf was treated with Zn

Ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) are a novel T1 contrast agent with good biocompatibility and switchable imaging signal that have not been widely applied for magnetic resonance imaging (MRI) because it is difficult to induce their relatively close ideal agglomeration. Here, by combining the microemulsion method with the biomineralization principle, a pH-responsive T2-T1 switchable MRI nanoprobe was constructed via the microemulsion-confined biomineralization of PEGylated USPIONs (PEG-USPIONs). The size of the formed CaCO

Semiconductor photocatalysis, as a means of utilizing stranded renewable solar resources, is now emerging as a viable and promising approach for increasingly severe water pollution. In this work, a high-performance photocatalytic system has been fabricated by immobilizing spiky TiO

As the global energy crisis and environmental pollution problems become increasingly severe, it is important to develop new energy capture and pollution management methods. Among these new technologies, photocatalysis has garnered significant interest because of its significant application prospects in harnessing pollution-free solar energy to degrade organic pollutants. From a fundamental scientific and technical perspective, improved optical frequency is a key research topic that provides a useful framework for studying the optical processes impacted by the local photonic environment. This type of study is especially pertinent because plasmonics emphasizes nonlinearity. Thus, near-infrared (NIR) catalysis has received considerable attention. In this review, we aimed to provide an integrated framework for NIR photocatalysis. We briefly introduce photocatalysis based on upconversion (UC) materials, including the efficiency of UC materials and the bination and energy transfer process between the semiconductor and UC particles as well as photoelectric response photocontrolled-delivery and photodynamic therapy based on NIR-responsive materials.

Herein, the CaTiO

Solar energy has received extensive attention as a renewable and sufficient energy source. Herein, inspired by the Janus wettability of lotus leaves, we have constructed a bioinspired hydrophilic-hydrophobic Janus hybrid system of carbonized carrot powder (CC powder)-modified cotton cloth with Nafion coating on one side (cotton cloth-NCC) for highly efficient solar steam generation. In cotton cloth-NCC, CC powder functions as a light absorber to achieve high light absorption, whereas the hydrophilic cotton cloth ensures efficient water transport. Meanwhile, the coating of Nafion establishes a hydrophobic-hydrophilic Janus structure, which can not only modulate water supply but also prevent salt deposition even with the high-concentration salt solution. The cotton cloth-NCC has been further shaped into a waved structure (w-cotton cloth-NCC) to increase the water evaporation area and achieve high light absorption (95%). Under 1 sun irradiation, w-cotton cloth-NCC yields a pure water steam generation rate of 1.88 kg m-2 h-1 and a seawater evaporation rate of 1.52 kg m-2 h-1. Furthermore, the w-cotton cloth-NCC also has a good purification effect on sewage: Escherichia coli can be completely removed, and the removal rate of Rhodamine B reaches 98.3%. The simple approach presented here for the construction of a high-efficient, low-cost, environmentally sustainable, long-term stable hydrophobic-hydrophilic Janus solar steam evaporator holds great promise for application in both environmental purification and photothermal conversion.

We present a facile two-step procedure for synthesizing spiky nanohybrids of titanium dioxide/gold (TiO2/Au) nanoparticles. In this process, spiky TiO2 is obtained using a hydrothermal method, followed by the introduction of plasmonic Au nanoparticles (AuNPs) via a photoreduction approach in which titanium fluoride and chloroauric acid tetrahydrate are used as raw materials. The photodegradation property of the resulting sample was evaluated according to the removal of Rhodamine B (RhB) and ciprofloxacin (CIP) via excitation with visible light. Additionally, the antimicrobial property of the spiky TiO2/Au nanoparticles was examined with respect to the suppression of the growth of Escherichia coli (E. coli). Compared with commercial TiO2, the spiky TiO2/Au nanoparticles exhibited a significantly enhanced photocatalytic efficiency in persistent organic pollutant degradation and bacteria inactivation under simulated environmental conditions. The photocatalysis mechanism primarily entails the combination of AuNPs with spiky TiO2 nanoparticles, which increases the optical path owing to the unique spiky structures of the latter. This results in an improved light-harvesting efficiency based on the localized surface plasmon resonance (LSPR) of AuNPs and the promotion of the charge-separation efficiency through electron-trap processes. These nanoparticles realize the objective of effectively addressing the inherent weaknesses of bare TiO2 and potentially facilitate new fitting approaches for applications in sewage treatment and marine antifouling paint.

The Fenton-like reaction has great potential in water treatment. Herein, an efficient and reusable catalytic system is developed based on atomically dispersed Fe catalyst by anchoring Fe atoms on nitrogen-doped porous carbon (Fe SA/NPCs). The catalyst of Fe SA/NPCs exhibits enhanced performance in activating peroxymonosulfate (PMS) for organic pollutant degradation and bacterial inactivation. The Fe SA/NPCs + PMS system demonstrates a high turnover frequency of 39.31 min

The energy transfer from upconversion nanoparticles (UCNPs) to photosensitizers has been widely used for generating reactive oxygen species (ROS) in photodynamic therapy (PDT) by near infrared (NIR) excitation. However, the poor spectral overlap of lanthanide ions and conventional photosensitizers leads to low PDT efficiency. In this study, we construct a multilayered upconversion nanoplatform with dual photosensitizers to efficiently use the UV and visible upconversion emissions in NIR-responsive PDT. The nanoplatform consists of three functional layers, which are the upconversion nanoparticle as a core, and light-sensitive conjugated polymer and apo-transferrin-titanocene (Tf@Tc) as shells. Under NIR irradiation, apparent energy transfer occurs from the core to the polymer and Tc components in the shell, producing reactive oxygen species and free radicals for cancer cell killing. In vitro cellular assays show the synergistic therapeutic effect of the conjugated polymer and Tc as photosensitizers. In vivo animal studies show that tumor growth is significantly inhibited in the mice receiving the theranostic platform and NIR irradiation. Based on these observations, the multilayered upconversion nanocomposites can find potential applications in NIR-mediated anti-tumor therapy.

A uniform ultra-small (10 nm) nanosized dendritic composite was reported for combined photothermal-chemotherapy, wherein a giant ring-like polymolybdate cluster was introduced for the first time as a photothermal therapeutic agent. The giant polyoxometalate cluster possesses strong absorption characteristics in the near infrared region, whereas it has never been applied for biomaterials due to its sensitivity towards environment and structural instability under physiological conditions. Herein, a cationic dendron bearing triethylene glycol monomethyl ether terminal groups was used to cover a giant polyanionic cluster Mo

Solar energy conversion is an important field gaining increasing interest. Herein, bio-inspired Au@TiO2 yolk-shell nanoparticles (NPs) have been prepared via a facial one-pot hydrothermal approach. The Au@TiO2 yolk-shell NPs can self-assemble into 3D-structure to form photoelectrode for photoelectric conversion. The obtained photoelectrode demonstrates a swift and stable photocurrent of 3.5 μA/cm2, which is 4.2 and 1.6 times higher than those of the photocurrents generated by the counterparts of commercial TiO2 and Au@TiO2 core-shell NPs, respectively. Moreover, compared to the commercial TiO2 and Au@TiO2 core-shell NPs, the Au@TiO2 yolk-shell NPs also exhibit superior photocatalytic activity, delivering a H2 evolution rate of 4.92 mmol/g h. The performance improvement observed for the Au@TiO2 yolk-shell NPs is likely contributed by two synergistic factors, i.e. the incorporation of AuNPs and the unique hollow structure, which benefit the activity by simultaneously enhancing light utilization, charge separation and reaction site accessibility. The rational design and fabrication of Au@TiO2 yolk-shell NPs hold great promise for future application in efficient solar energy conversion.

Optical methods such as absorptiometry, fluorescence, and surface plasmon resonance have long been explored for sensing glucose. However, these schemes have not had the clinical success of electrochemical methods for point-of-care testing because of the limited performance of optical sensors and the bulky instruments they require. Here, we show that an ultrasensitive optical transducer can be used for wireless glucose monitoring via a smartphone. The optical transducer combines oxygen-sensitive polymer dots (Pdots) with glucose oxidase that sensitively detect glucose when oxygen is consumed in the glucose oxidation reaction. By judicious design of the Pdots with ultralong phosphorescence lifetime, the transducer exhibited a significantly enhanced sensitivity by 1 order of magnitude as compared to the one in a previous study. As a result, the optical images of subcutaneous glucose level obtained with the smartphone camera could be utilized to clearly distinguish between euglycemia and hyperglycemia. We further developed an image processing algorithm and a software application that was installed on a smartphone. Real-time dynamic glucose monitoring in live mice was demonstrated with the smartphone and the implanted Pdot transducer.

A self-standing macroporous noble metal-zinc oxide (ZnO) sponge of robust 3D network has been fabricated through in-situ growth method. The key to the construction of the bioinspired sponge lies in the choice of commercial polyurethane sponge (CPS) with interconnected and junction-free macroporous structure as the skeleton to support Au/ZnO nanorods (Au/ZnONRs). The resultant Au/ZnO/CPS not only exhibits hierarchical structures representing physical features of CPS, but also demonstrates durable superior photocatalytic activity and hydrogen generation capability. In addition, we have adopted various irradiations to investigate the effect of UV light and visible light on the photocatalytic performance of Au/ZnO/CPS individually. In detail, the photocatalytic properties of Au/ZnO/CPS and ZnO/CPS have been monitored and compared under irradiations of different wavelengths (200–1100, 350–780, 200–420 and 420–780 nm) for 90 min to reveal the effect of irradiation wavelength on the activity of photocatalysts. A possible mechanism between irradiation wavelength and photocatalytic degradation efficiency is proposed. The facile in-situ growth approach presented herein can be easily scaled up, affording a convenient method for the preparation of self-standing 3D macroporous materials, which holds great potential for the application in both environmental purification and solar-to-hydrogen energy conversion.

A uniform ultra-small (

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.

A three-dimensional (3D) graphene macroporous foam substrate with ZnO nanorod array was developed for specific and non-invasive detection of circulating tumor cells (CTCs). With the help of the epithelial cell adhesion molecule antibody (anti-EpCAM) and the array structure, the EpCAM-positive CTCs can adhere on the detection substrate (rGO-ZnO-antiEpCAM foam). Moreover, the resistance and the electrochemical impedance spectroscopy (EIS) of the rGO-ZnO-antiEpCAM foam was changing during the CTCs adhering process with high sensitivity. Compared to the EpCAM-negative cancer cell, the resistance of the substrate is rising with the amount of the EpCAM-positive CTCs. The possible reason is that the negative charges of CTCs affected the conductivity of the p-type reduced graphene oxide (rGO), and when CTCs were adhering to the rGO-ZnO-antiEpCAM foam, the resistance of the rGO-ZnO-antiEpCAM foam increased. In addition, the EIS measurement also shows the regular changes during the adhering process. From the equivalent circuit modeling of EIS, the charge transfer resistance (Rct) on the surface of the rGO-ZnO-antiEpCAM foam electrode had a linear growth. This may be due to the fixation of negatively charged Breast cancer cells (MCF-7) on the substrate, the charge transfer process was hindered, which caused the semicircle domain of the EIS curve to expand significantly with time. These results reveal that CTCs can not only be specifically adhered on the rGO-ZnO-antiEpCAM foam, but also the electrical microenvironment of the detection substrate was changed during CTCs adhering process. The construction of the detection substrate, the measurement and analysis methods of the electrical signals are of great significance in CTCs acquisition and sensing, which will provide an effective strategy for the real-time monitoring of CTCs at the clinic.

Many studies have been devoted to enhancing photocatalytic activity of hydrogen generation by water splitting in recent years. Herein, a well-defined 3D flowerlike mesoporous photocatalyst (kermesinus BiOI, K-BiOI) was successfully prepared through UV–Vis-Light driving method. The X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and surface photovoltage (SPV) tests confirmed that the oxygen vacancies (OVs) were introduced onto the surface of BiOI, which resulted that the color of BiOI changed from normal orange to kermesinus. The successful introduction of OVs led to the absorption range of K-BiOI stretched. Although the OVs are introduced on the surface, the main body of the material is still BiOI. Furthermore, K-BiOI exhibited a remarkably improved hydrogen production rate of 6.51 mmol g−1 h−1 under UV–Vis-light irradiation, which was 21-fold higher than that of BiOI under UV light irradiation. The OVs on the K-BiOI surface could form a defect state lying near the conduction band minimum of the photocatalyst and act as an electron scavenger delaying the photogenerated carrier recombination during the photoreaction process. The present work provides a new approach to introduce OVs on the surface of BiOI, which can provide a new strategy of catalyst preparation for the efficient H2 production.

A bio-inspired graphene/Au@ZnO photoelectrode has been prepared via breath figure method, in which Au@ZnO nanospheres were uniformly distributed in the whole honeycomb film. The size of the honeycomb holes effects the light using efficiency. The honeycomb film with smaller holes in more ordered array shows better antireflective property. All the formed graphene/Au@ZnO honeycomb photoelectrodes show a fast, stable, and reversible response of photocurrent accompanied by each switch-on and switch-off event. Au@ZnO-modified graphene honeycomb film can combine the advantages of increased light harvesting provided by honeycomb structure, efficient charge separation from Au nanoparticles (NPs), and efficient electron transfer provided by graphene. Au@ZnO- modified graphene honeycomb film shows a two-fold increase of photocurrent generation than ZnO-modified graphene honeycomb film and a three-fold increase of photocurrent generation than Au@ZnO-modified graphene smooth film, respectively. The rational design and engineering of multi components with different functions in a hybrid bio-inspired structure hold great promise for further efficient solar energy conversion devices.

Tm 3+ doped β-NaYbF 4 with different aspect ratios has been synthesized by a facile hydrothermal method. A different morphology and size of β-NaYbF 4 microrods were obtained by changing the NaF/RE (RE = Yb,Tm, 99.5% Yb 3+ , 0.5% Tm 3+ ) molar ratio. The morphology and size of products were explored by SEM, and the influences of the NaF/RE molar ratio on the microrod size were evidenced by XRD. It is shown that the size and morphology of the products can be precisely controlled by modulation of the NaF/RE molar ratio. β-NaYbF 4 microrods with 35 μm in length and 7.5 μm in diameter were prepared when NaF/RE molar ratio is 6. Intense ultraviolet emissions at 290 nm, 345, and 361 nm and visible emissions at 451 and 494 nm were observed in Tm 3+ doped NaYbF 4 microrods with an excitation of a 980 nm diode laser. The effect of NaF/RE ratio on growth rate has been proposed.

A self-standing three-dimensional (3D) nanocomposite foam of Au/ZnO/reduced graphene oxide (rGO) has been fabricated via a facile and convenient template-directed approach. This is the first report of self-standing ternary macroporous foam consisting of noble metal, ZnO and rGO, which can be directly used in photocatalytic degradation and photocurrent generation, free of any inactive binders or substrates. The resultant 3D Au/ZnO/rGO foam exhibits superior photocatalytic activity than binary ZnO/rGO foam and flat Au/ZnO/rGO film, demonstrating 94% Rhodamine B degradation within 180 minutes under 200–780 nm irradiation and good cycling stability after 5 photodegradation cycles. Moreover, the Au/ZnO/rGO foam expresses a swift and steady photocurrent of 0.055 mA cm −2 , which is 3 and 24 times higher than those photocurrent generated by ZnO/rGO foam without Au nanoparticle (AuNP) decoration and flat Au/ZnO/rGO film electrode respectively. The observed performance enhancement is likely contributed by the hierarchical macroporous structure of conductive Au/ZnO/rGO foam, which can not only improve the light utilization, but also facilitate electron transport by promoting the photo-induced charge separation. Furthermore, the AuNPs loaded on ZnO can function as an electron sink to enhance photocurrent generation and photocatalytic property. The simple approach presented here holds great promise for the application in both environmental purification and photoelectric conversion.

A self-supporting macroporous graphene foam was prepared by template method. This foam which was fabricated by reduced graphene oxide (rGO) has good conductivity, and it also has large surface both in the foam interior and outside surface. The surface can offer a good platform to introduce active materials into the foam. TiO2 nanorods were grown on the foam framework using hydrothermal synthesized method. Due to a well-ordered macroporous structure and high conductivity of the reduced graphene oxide scaffold, the light utilizing in the composite TiO2/rGO foam will increase, and the photoinduced electron also transports quickly to the substrate. These advantages resulted in a better photocurrent response. Furthermore, the well photo induced electron transports will also lead to better photocatalytic degradation property. The enhanced absorption performance, photocurrent response, photocatalytic degradation property of composite TiO2/rGO foam will make this foam a promising material for practical applications in the environmental protection field.

Two kinds of hydrophilic conjugated polymer, poly[9,9-bis((6-N,N,N-trimethylammonium)hexyl)fluorine-alt-co-(1,4-benzo-{2,1′,3}-thiadiazole] (PFBD) with cationic groups and poly[9,9-bis(4′-sulfonatobutyl)fluorine-alt-co-(1,4-benzo-{2,1′,3}-thiadiazole)] sodium salt (PFSBT) with anionic groups, were prepared by Suzuki method. The as-prepared conjugated polymers were formed nanoparticles (NPs) with the diameter of ~20 nm in water. Under a 488 nm laser excitation, the PFBD shows an emission peak at 560 nm and with the quantum yield of ~26%, while the PFSBT shows an emission peak at 575 nm with the quantum yield of ~4%. We investigated the cellular uptake and cell viability of two conjugated polymer NPs (CPNPs) on human gastric adenocarcinoma (SGC-7901). Both of CPNPs show low cytotoxicity by MTT assay, even at the concentration of 40 ppm. Flow cytometers studies indicate that the fluorescence intensity of PFBD NPs is stronger than that of PFSBT NPs. These results would provide a basic experiment evidence in the fluorescence imaging field.