RESUMO
Multidimensional bimetallic Pt-based nanoarchitectonics are highly promising in electrochemical energy conversion technologies because of their fancy structural merits and accessible active sites; however, hitherto their precise template-free fabrication remains a great challenge. We report a template-free solvothermal one-pot approach for the rational design of cocentric PtNi multicube nanoarchitectonics via adjusting the oleylamine/oleic acid ratio with curcumin. The obtained multidimensional PtNi multicubes comprise multiple small interlace-stacked nanocube subunits assembled in spatially porous branched nanoarchitectonics and bound by high-index facets. The synthetic mechanism is driven by spontaneous isolation among prompt nucleation and oriented attachment epitaxial growth. These inimitable architectural and compositional merits of PtNi multicubes endowed the ethanol oxidation mass and specific activity by 5.6 and 9.03 times than the Pt/C catalyst, respectively, along with the enhancement of methanol oxidation mass activity by 2.3 times. Moreover, PtNi multicubes showed superior durability and a higher tolerance for CO poisoning than the Pt/C catalyst. This work may pave the way for tailored preparation of Pt-based nanoarchitectonics for myriad catalytic reactions.
RESUMO
This work describes a new chemiluminescence (CL) system that is composed of lucigenin and carbon dots (CDs). The CDs display absorption peak at 260 nm and fluorescence with a emission peak centered at 524 nm (photo-excited at 470 nm). They were synthesized by hydrothermal treatment of starch and characterized by Fourier transform infrared spectroscopy, high resolution transmission electron microscopy, UV-vis absorption spectra and fluorescence spectra. The effects of oxygen and free radical scavengers on the CL system and on the CL spectra were investigated to elucidate the CL mechanism. It is found that L-cysteine (Cys) enhances the blue CL of the lucigenin-CD system by 59%. The finding was used to design a method for the determination of Cys. CL increases linearly in the 10.0 to 100 µM Cys concentration range, and the detection limit is 8.8 µM (at an S/N ratio of 3). The assay is highly selective over other amino acids. Conceivably, this novel CL system paves the way to numerous new assays based on the use of lucigenin. Graphical abstractSchematic representation of the carbon dots enhanced lucigenin chemiluminesence.
RESUMO
Perylene and its derivatives are often used in many analytical fields, but its electrochemiluminescence (ECL) behavior has been rarely reported. Here, a novel anodic ECL of 3,4,9,10-perylenetetracarboxylic acid (PTCA)/oxamic hydrazide (OHZ) has been investigated for the first time with OHZ as the coreactant. The mechanism of the PTCA/OHZ ECL system is discussed. This ECL system enables the detection of OHZ with a linear range from 0.0626 to 312.5 µM and a detection limit of 21 nM (S/N = 3). Moreover, a highly sensitive method for tannic acid determination has been developed based on the effective quenching of PTCA/OHZ ECL by tannic acid. The proposed method shows a linear range of 0.05-320 µM with the limit of detection at 5 nM for tannic acid (S/N = 3). This study indicates that PTCA/OHZ shows great potential for application in ECL analysis as a new low-cost ECL system.
RESUMO
Lucigenin-riboflavin chemiluminescence is reported for the first time. Moreover, most dopamine chemiluminescence (CL) detection methods are based on the quenching of CL by dopamine. In contrast, we find that dopamine can significantly enhance lucigenin/riboflavin CL and establish a highly sensitive turn-on method for dopamine detection based on the enhancement of lucigenin/riboflavin CL. Under the optimal conditions, the CL intensity of the lucigenin/riboflavin system increased linearly with the concentration of dopamine in the range of 0.0056-55.56 µM, and the limit of detection is 1.87 nM.