Hengxi He,Weirui Chen,Jiaxin Zhou,Xukai Li,Jing Wang,Laisheng Li
The sluggish Me (n+m)+ / Me n+ redox cycle greatly restrained the catalytic ozonation performance of metal-based catalysts. To break this bottleneck, we adopted an interfacial oxidation reaction to create electron-deficient/rich centers within carbon skeleton derived from MOF (C-MOF) by utilizing the electronegativity difference between cerium (Ce) and manganese (Mn), and evaluated its catalytic ozonation activity with ibuprofen (IBP) as model pollutant. XPS, H 2 -TPR, LSV and EPR characterizations as well as DFT calculation demonstrated that there existed electron-deficient Ce sites and electron-rich Mn sites on CeO x /MnO x /C-MOF. Under the co-function of Ce and Mn sites, CeO x /MnO x /C-MOF/O 3 process achieved 100% IBP removal in 90 min, which was 3.1 times of sole ozonation process. IBP could be absorbed at the electron-deficient Ce center and directionally donate its electron to the O 3 around electron-rich Mn center. Singlet oxygen ( 1 O 2 ) played the major role in IBP degradation. Cl − , HCO 3 − , NO 3 − and SO 4 2− demonstrated limited inhibitions on IBP degradation. This work provided a sustainable strategy for breaking the rate-limiting step in the traditional catalytic ozonation.
N 6 -methyladenosine (m 6 A) modification has an impact on RNA metabolism, and it has been demonstrated that m 6 A regulatory mechanisms play an important role in tumorigenesis and may serve as a potential hepatocellular carcinoma (HCC) marker. We constructed a dual-signal amplification strategy electrochemical biosensor based on biocatalytic silver deposition and hybridization chain reaction (HCR). Enzymatic silver deposition was performed on the electrode and detected by linear sweep voltammetry (LSV), which was used for the quantitative detection of m 6 A. There was a nice linear relationship between the current response values and the logarithm of the m 6 A RNA concentration in the range of 0.5 pM-5 μM, with a detection limit as low as 25 fM. The concentration of m 6 A detected by the sensor constructed in this work is consistent with the results obtained using commercial colorimetric immunoassays . What's more, the analysis of m 6 A RNA in the serum of HCC patients using the developed sensor showed the high analytical efficiency of the designed strategy, which was superior to three other markers (AFP, CEA, CA199). The constructed electrochemical biosensor has good sensitivity, specificity and reproducibility for the detection of m 6 A RNA, and the sensing platform has promising clinical applications in the diagnosis and prognosis of HCC.
E. Loni,M.H. Siadati,A. Shokuhfar,D. Leybo,D. Kuznetsov
Water splitting, an assuring concept for future sustainable hydrogen/oxygen production, is intensely dependent on the efficiency of catalysts to promote the oxygen evolution reaction (OER) or hydrogen evolution reaction (HER). In this regard, finding high-performance electrocatalysts for OER remains amongst the key challenges in water splitting. Here, for the first time, an aerosol-assisted spray pyrolysis method was applied to synthesize hollow spherical powder possessing nano-thick walls of sodium-cobalt pyrophosphate (Na 2 CoP 2 O 7 ) electrocatalyst for OER application. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses were carried out for investigating the structure, composition , and morphology of the electrocatalyst powder. The electrocatalytic performances of the as-synthesized Na 2 CoP 2 O 7 powder along with its composites with Vulcan XC-72 (conductive carbon black), reduced graphene oxide (rGO) and N-doped rGO (N-rGO) were studied by the linear sweep and cyclic voltammetry (LSV and CV). The best sample synthesized was Na 2 CoP 2 O 7 /rGO (50/50 wt%), which required only 240 mV overpotential to produce a current density of 10 mA cm −2 .
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