Photocatalytic CO2 reduction into fuels has been an attractive research topic. Herein, Ag and TiO2 nanoparticles co-loaded zeolite TS-1 (Ag–TiO2/TS-1) were synthesized by the ion-exchange and ...subsequently in-situ photodeposition method. The obtained Ag–TiO2/TS-1 sample has a high surface area and rich Ti3+-Vo defects and as well as highly dispersed Ag nanoparticles. As expected, the sample Ag–TiO2/TS-1 not only shows high CO2 adsorption capacity, but also improves the separation efficiency of photogenerated electron-hole pairs. As a result, only CO and CH4 can be detected on the sample Ag–TiO2/TS-1 in the photocatalytic CO2 conversion, and the competing H2 evolution can be completely suppressed, suggestive of its high selectivity. The super photocatalytic activity toward CO2 reduction can be ascribed to the synergistic effect among highly dispersed Ag nanoparticle, the support zeolite TS-1 and TiO2 with highly exposed {101} planes.
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•A novel Ag and TiO2 nanoparticles co-loaded zeolite TS-1 (Ag–TiO2/TS-1) was prepared.
•Ag–TiO2/TS-1 has highly exposed {101} planes and rich Ti3+-Vo defects.
•Ag–TiO2/TS-1 exhibits high CO2 adsorption capacity.
•Ag–TiO2/TS-1 exhibits super separation efficiency of photogenerated charges.
•Only CO and CH4 can be detected on the sample Ag–TiO2/TS-1 in the CO2 reduction.
In consideration of comparable ionic radius between indium ions and tin ions, indium-doped SnS
2
(In/SnS
2
) sample was designed and synthesized by one-pot solvothermal method. Its multi-level ...structure composed of 10-nm-thick ultrathin sheets can enhance utilization efficiency of solar light. The substitution of trivalent indium ions for tetravalent tin ions causes indium to form a negative charge center and simultaneously produces sulfur vacancies positively charged. As expected, the production of hydrogen on doped sample is up to 470 µmol g
−1
, which is about twice as high as that on SnS
2
. This is attributed to hierarchical structure composed of ultrathin sheets and effective attraction of hydrogen ions by negative charge on trivalent indium ions. The results suggest that doping the ions whose ionic radius is close to the radius of the anions or cations in the material into the lattice sites may provide a new tactic for the design of semiconductor photocatalytic materials.
The problems of severe oxygen-dependent hypoxia and fluorescence aggregation-caused quenching (ACQ) of conventional photosensitizers (PSs) in tumour cells with a hypoxic microenvironment have impeded ...the development of photodynamic therapy (PDT) for cancer treatment. To overcome these shortcomings, PDT PSs based on free radical reactive oxygen species (ROS) with aggregation-induced emission (AIE) characteristics have attracted considerable attention recently. Herein, we design and synthesize two AIE-PSs,
OMEPY
and
OMEPYH
, based on the benzophenone core. Detailed photophysical and photochemical study has shown that these two AIE-PSs produce ROS based on both type I (electron transfer) and both type II (energy transfer) pathways. The
in vitro
experimental results reveal that
OMEPYH
can be used for mitochondria-targeted PDT due to the interaction of its positively charged methylpyridinium group with the negative mitochondrial membrane
via
electrostatic interactions. This work provides a strategy for utilizing the benzophenone core to design efficient AIE-PSs for the image-guided PDT modality.
AIE active photosensitizer of
OMEPYH
with benzophenone core and methylpyridinium group exhibited highly efficient generation of both type-I and type-II reactive oxygen species, which can be used for mitochondria-targeted photodynamic therapy (PDT).
In this paper a nanocomposite prepared by graphene (GR) and SnO2 nanosheets was used to modify a N-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode. The presence of GR–SnO2 ...nanocomposite on the electrode surface exhibited synergistic effects to improve the electrochemical performance of the modified electrode. Electrochemical behaviors of dopamine (DA) on the electrode were evaluated by cyclic voltammetry and differential pulse voltammetry. The results indicated that the GR–SnO2 nanocomposite modified electrode displayed high electrocatalytic activity to the oxidation of DA with the increase of the redox peak currents and the decrease of the peak-to-peak separation. Under the selected conditions the oxidation peak current was proportional to the DA concentration in the range from 0.5 to 500.0μmol/L with a detection limit of 0.13μmol/L (S/N=3). The modified electrode showed excellent selectivity and sensitivity even in the presence of high concentration of uric acid. The proposed method was applied to determine DA content in real samples with satisfactory results.
A biocompatible sensing platform based on graphene (GR) and titanium dioxide (TiO₂) nanorods for the immobilization of hemoglobin (Hb) was adopted in this paper. The GR-TiO₂-Hb composite-modified ...carbon ionic liquid electrode was constructed through a simple casting method with Nafion as the film forming material. UV-Vis and FT-IR spectra confirmed that Hb retained its native structure in the composite film. Direct electron transfer of Hb incorporated into the composite was realized with a pair of quasi-reversible redox waves appeared, indicating that the presence of GR-TiO₂ nanocomposite on the electrode surface could facilitate the electron transfer rate between the electroactive center of Hb and the substrate electrode. Hb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.6 to 21.0 mmol L⁻¹. These results indicated that GR-TiO₂ nanocomposite could be a friendly biocompatible interface for immobilizing biomolecules and keeping their native structure. The fabricated biosensor displayed the advantages such as high sensitivity, good reproducibility and long-term stability.
Four undescribed pyranone derivatives, named ascomycopyrones A-D (
-
), as well as one known analogue simplicilopyrone (
) (this is the first study to report the absolute configuration), were ...isolated from the endophytic fungus
sp. FAE17 derived from the flowers of
. The structures of these pyranones were identified by comprehensive spectroscopic and MS analyses, and the absolute configurations were determined by their experimental and quantum chemical electronic circular dichroism (ECD) calculations. All isolated compounds were tested for various bioactivities, including antibacterial, cytotoxic activity, and NO inhibitory activity. Unfortunately, none of the compounds showed significant bioactivities.
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► Poly(methylene blue) functionalized graphene was electrodeposited on the electrode. ► The fabricated electrode showed better electrochemical performances. ► Dopamine was sensitive ...detected by the modified electrode.
An ionic liquid 1-butylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE) was used as the substrate electrode and a poly(methylene blue) (PMB) functionalized graphene (GR) composite film was co-electrodeposited on CILE surface by cyclic voltammetry. The PMB–GR/CILE exhibited better electrochemical performances with higher conductivity and lower electron transfer resistance. Electrochemical behavior of dopamine (DA) was further investigated by cyclic voltammetry and a pair of well-defined redox peaks appeared with the peak-to-peak separation (ΔEp) as 0.058V in 0.1molL−1 pH 6.0 phosphate buffer solution, which proved a fast quasi-reversible electron transfer process on the modified electrode. Electrochemical parameters of DA on PMB–GR/CILE were calculated with the electron transfer number as 1.83, the charge transfer coefficients as 0.70, the apparent heterogeneous electron transfer rate constant as 1.72s−1 and the diffusional coefficient (D) as 3.45×10−4cm2s−1, respectively. Under the optimal conditions with differential pulse voltammetric measurement, the linear relationship between the oxidation peak current of DA and its concentration was obtained in the range from 0.02 to 800.0μmolL−1 with the detection limit as 5.6nmolL−1 (3σ). The coexisting substances exhibited no interference and PMB–GR/CILE was applied to the detection of DA injection samples and human urine samples with satisfactory results.
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► Ploy-l-lysine modified glassy carbon electrode was prepared by electropolymerization. ► A carboxyl functionalized graphene oxide was synthesized and decorated on PLLy/GCE. ► ...Electrochemical DNA biosensor based on GO-COOH/PLLy/GCE was fabricated. ► The tlh gene related to vibrio parahaemolyticus was detected successfully.
A carboxyl functionalized graphene oxide (GO-COOH) and electropolymerized ploy-l-lysine (PLLy) modified glassy carbon electrode (GCE) was fabricated and used for the construction of an electrochemical deoxyribonucleic acid (DNA) biosensor. The NH2 modified probe ssDNA sequences were immobilized on the surface of GO-COOH/PLLy/GCE by covalent linking with the formation of amide bonds, which was stable and furthur hybridized with the target ssDNA sequence. Differential pulse voltammetry (DPV) was used to monitor the hybridization events with methylene blue as electrochemical indicator, which gave a sensitive reduction peak at −0.287V (vs. SCE). Under the optimal conditions the reduction peak current was proportional to the concentration of tlh gene sequence in the range from 1.0×10−12 to 1.0×10−6molL−1 with a detection limit as 1.69×10−13molL−1 (3σ). The polymerase chain reaction products of tlh gene from oyster samples were detected with satisfactory results, indicating the potential application of this electrochemical DNA sensor.
A carbon/ionic liquid paste electrode (CILPE) prepared by 1-hexylpyridinium hexafluorophosphate as the binder was used as the substrate electrode. A layer of graphene oxide (GO) film was cast on ...CILPE surface (GO/CILPE) and the electropolymerization of acridine orange (AO) on electrode was further realized by cyclic voltammetry in the potential range from −1.40V to 1.40V, which could simultaneously reduce GO to graphene (GR) electrochemically. The fabricated PAO-GR/CILPE exhibited good electrochemical performances with higher conductivity and lower electron transfer resistance. Electrochemical behaviors of rutin were further investigated on the modified electrode in 0.1mol/L pH 2.0 phosphate buffer solution by cyclic voltammetry with a pair of well-defined redox peaks appeared. The peak-to-peak separation (ΔEp) was calculated as 0.076V, which proved a fast quasi-reversible electron transfer process and the electrochemical parameters of rutin on PAO-GR/CILPE were calculated. Under the optimal conditions, the linear relationship between the oxidation peak current of rutin and its concentration was obtained in the range from 0.03 to 800.0μmol/L with the detection limit as 8.33nmol/L (3σ). The PAO-GR/CILPE showed good selectivity, stability and reproducibility, which was further applied to detect rutin tablet samples with satisfactory results.
The diffusion and local structure of eight normal alkanols in 1-octanol at infinite dilution from 298 to 370 K have been investigated via molecular dynamics simulation. For short-chain
n
-alkanols, ...the simulated infinite dilute diffusion coefficients
D
12
are in good agreement with the experimental data, while for long-chain
n
-alkanols, the simulated
D
12
overestimate the experimental data. Meanwhile, the local structures are characterized by calculating the radial distribution functions, hydrogen bond, radius of gyration, and end-to-end distance. It is interesting that the average number of hydrogen bonds decreases as the chain length of
n
-alkanols increases from methanol to 1-heptanol, but unexpectedly, the average number of hydrogen bonds for 1-nonanol begins to increase. The simulation results demonstrate that a kind of intertwist effect through alkyl chain-chain interactions and caused by the molecular flexibility could explain the abnormal change of hydrogen bond number and the serious overestimation of simulated
D
12
for long-chain
n
-alkanols.
