Well-redispersed ceria nanoparticles (CeO 2 NPs) were synthesized by a simple hydrothermal method. The prepared CeO 2 NPs exhibited excellent catalytic activity towards classical peroxidase substrate 3,3,5,5-tetramethylbiphenyl dihydrochloride (TMB$2HCl) in the presence of H 2 O 2 , based on which a colorimetric method that is highly sensitive and selective was developed for glucose detection. The composition, structure, morphology and peroxidase-like catalytic activity of CeO 2 NPs are investigated in detail by using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FT-IR), thermal analysis (TG) and UV-vis absorption spectroscopy. According to this method, the detection of H 2 O 2 and glucose are in linear range from 6.0 Â 10 À7 to 1.5 Â 10 À6 mol L À1 and 6.6 Â 10 À6 to 1.3 Â 10 À4 mol L À1 , with the detection limit down to 5.0 Â 10 À7 mol L À1 H 2 O 2 and 3.0 Â 10 À6 mol L À1 glucose, respectively. Further, this simple, cheap, highly sensitive and selective colorimetric method for glucose detection was successfully applied for the determination of glucose in human serum samples.

Graphene sheets decorated with SnO 2 nanoparticles were prepared through a facile hydrothermalassisted in situ synthesis route. According to the XPS, XRD, FESEM and TEM analysis, rutile SnO 2 nanocrystals were exclusively deposited on graphene sheets with high density and high uniformity to form layered composite sheets. Propanal, a common volatile organic compound, was selected as a model to investigate the cataluminescence (CTL) sensing properties of the SnO 2 /graphene composite in this paper. It was found that the strong CTL emission could be generated due to the catalyzing oxidization of propanal on the surface of SnO 2 /graphene composite and this composite was an efficient sensing material for propanal. We further studied the analytical characteristics of the CTL sensor based on SnO 2 /graphene composite sensing material for propanal under the optimal experimental conditions. The linear range of the propanal gas sensor was 1.34-266.67 mg mL À1 (r ¼ 0.9987), over two orders of magnitude, and the detection limit was 0.3 mg mL À1 (S/N ¼ 3).

Herein, we present a novel strategy based on a "turn-on" persistent luminescence imaging chemical system of graphitic carbon nitride for detecting biothiols in biological fluids. Graphitic carbon nitride (g-C3N4) as persistent luminescence probe is fabricated via a new procedure based on pyrolysis of guanidine hydrochloride under ambient atmospheric conditions. The prepared g-C3N4 nanosheets give intensively long-persistent luminescence that can avoid interference from biological media such as tissue autofluorescence and scattering light. The original persistent luminescence of g-C3N4 turns off due to the adsorption of silver ion (Ag(+)) onto g-C3N4 materials with an electron transfer process. The presence of biothiols induces the onset of persistent luminescence emission by interrupting the quenching interaction, thereby turning on the imaging probe. The approach exhibits high specificity and high sensitivity to biothiols with low detection limit for cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) with 6.4, 8.1, and 9.6 nM, respectively. It is also successfully applied for imaging detection of biothiols in human urine, plasma, and cell lysates, demonstrating its great value of practical application in biological systems.

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A metal (Co)-Organic Framework (Co-MOF) was first found to catalyze the chemiluminescence (CL) of luminol. On the basis of X-ray photoelectron spectroscopy, powder X-ray diffraction, CL spectral, UV-visible absorption spectral, and electron spin resonance (ESR) spectral studies, as well as the research of the influence of various free radical scavengers, a possible CL mechanism was proposed. The enhanced CL might be attributed to the formation of a peroxide analogous complex between the oxygen-related radicals and the active metal site of the Co-MOF material. The established Co-MOF-luminol CL system was successfully applied to determine L-cysteine (CySH), based on the selective and sensitive enhancing effect of CySH on this CL system. Under the optimized conditions, CySH was selectively detected in the range 0.1-10 μM with a detection limit of 18 nM. This novel CL system obviously gives impetus to the new research field of metal-organic frameworks (MOFs) in chemiluminescence.

The present study outlines a one‐step route to the preparation and functionalization of graphene nanosheets from graphene oxide using tea polyphenols as a simultaneous reductant and functionalization reagent. This method uses a “green” reductant and is free of additional functionalization reagents, thus it is environmentally friendly, simple, and low‐cost. The resulting functionalized graphene nanosheets have a mostly single‐layer structure, are stable, and have very good water dispersibility. The structure, composition, and morphology of the resulting material were characterized by using various methods including, X‐ray diffraction (XRD), UV/Vis spectroscopy, Raman spectroscopy, detailed X‐ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Among other possible applications of the functionalized graphene, we discuss its use as an adsorbent for heavy‐metal ions in aqueous solutions.