Xiulin Yang

High electrocatalytic activity of PtRu nanoparticles supported on starch-functionalized multi-walled carbon nanotubes for ethanol oxidation

The high-performance PtRu electrocatalysts on ethylenediamine modified cross-linked starch-functionalized multi-walled carbon nanotubes have been synthesized by the polyol process. The method was simple and can be carried out at room temperature without the use of expensive chemicals or corrosive acids, thus preserving the integrity and the electronic structure of the nanotubes. Transmission electron microscopy revealed that the PtRu is well distributed with no formation of aggregates. Cyclic voltammetry and chronoamperometry studies indicate the material had a higher electrochemically active surface area, electrocatalytic activity and stability for the electro-oxidation of ethanol compared to that of PtRu electrocatalysts supported on conventional acid-treated multi-walled carbon nanotubes and on XC-72 carbon black.

A hybrid catalyst of Pt/CoNiO2 on carbon nanotubes and its synergetic effect towards remarkable ethanol electro-oxidation in alkaline media

Herein, a hybrid catalyst of Pt/CoNiO2 on carbon nanotubes (Pt/CoNiO2–CNTs) has been successfully synthesized by a facile and cost-effective method, and its crystal structures, chemical valence states, and morphologies have been characterized in detail. CO stripping voltammograms reveal that the adsorbed COads on the active sites of the Pt/CoNiO2–CNT catalyst is easily oxidized at a lower potential (−0.60 V) as compared to the Pt particles on rGO (−0.35 V) and acid-treated CNTs (−0.36 V). Cyclic voltammograms demonstrate that the designed Pt/CoNiO2–CNT catalyst possesses an ultrahigh electrocatalytic activity (1136.2 mA mgPt−1) for ethanol oxidation, which is 5.1 and 3.0 times higher than that of Pt/rGO (221.6 mA mgPt−1) and Pt/CNTs (375.4 mA mgPt−1), respectively. The Tafel plot of Pt/CoNiO2–CNTs is 205 mV dec−1, indicating much faster reaction kinetics than that of the compared catalysts. In addition, the outstanding long-term stability indicates that the designed Pt/CoNiO2–CNT catalyst exhibits expected application prospects in direct alkaline ethanol fuel cells. Moreover, the catalytic mechanism of the hybrid Pt/CoNiO2–CNTs has been proposed and discussed via C2 and C1 pathways with respect to the final products for CH3COO− and CO32−, respectively.

A simple and rapid dual-cycle amplification strategy for microRNA based on graphene oxide and exonuclease III-assisted fluorescence recovery

A simple microRNA detection method by combining Graphene Oxide (GO) fluorescence quenching with exonuclease III (Exo-III) aided cycling amplification was developed. Three DNA probes, a FAM-containing ssDNA (P-DNA), hairpin probe 1 (H1) and hairpin probe 2 (H2), were masterly designed. In the presence of the target, H1 and H2 are digested by Exo III because of the target DNA-induced two-step hybridization and a series of single stranded DNAs (ssDNAs) are released; ssDNA and probe P are completely complementary to form double-stranded DNA. This duplex is not easily adsorbed by GO, thus weakening the fluorescence quenching of FAM. In the absence of target miRNA, the ssDNA probes are fully adsorbed on the GO resulting in fluorescence quenching by π–π stacking. This strategy provides a highly sensitive fluorescence detection of microRNA with a limit of detection down to 21.40 pM, and also exhibits good selectivity. The results show that this simple and economical strategy has underlying application value in biomedical research.