ABSTRACT
Developing efficient, environmentally friendly and cost-effective non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is essential to alleviate the energy crisis and environmental pollution. Herein, we report a simple and practical method to prepare non-precious metal catalysts, namely iron-modulated Ni3S2 (Fe-Ni3S2/NF) on nickel foam, by growing a Ni-MOF directly on 3D porous conductive nickel foam, followed by the formation of Ni-MOF-based Prussian blue analogs (Ni-MOF@PBA) via in situ cation exchange reactions, which are further sulfidated to iron-modulated Ni3S2. Based on a series of characterization results, it is confirmed that iron acts as a modulator at the Ni active site, leading to electron depletion, thereby modulating the electron spin state and optimizing the binding energy of key reaction intermediates, resulting in highly exposed active sites and acceleration of OER reaction kinetics. The synthesized Fe-Ni3S2/NF exhibits excellent activity in alkaline media, which needs overpotentials of only 232 mV and 287 mV to drive current densities of 10 mA cm-2 and 50 mA cm-2, respectively. Additionally, Fe-Ni3S2/NF exhibits excellent stability for at least 24 h during the OER process. This work presents a rational design and synthesis of transition metal-based catalysts with nanocone structures, providing a new strategy for assembling advanced materials and insights for exploring various energy storage and conversion systems.
ABSTRACT
Electrochemical water splitting is a promising approach to produce hydrogen gas, but sluggish four-electron transfer of the oxygen evolution reaction (OER) severely limits the overall energy conversion efficiency of water splitting. Herein, as an excellent OER electrocatalyst, a technique of synthesizing Fe doped CoNiSe2 nanosheet (Fe-CoNiSe2) whole series using CoFe prussian blue analog produced by Co-ZIF-L reaction as a template is proposed here. The introduction of iron ions promotes the redistribution of the cobalt-nickel charge density, which enhances the OER kinetics. In view of the abovementioned points, Fe-CoNiSe2/NF has excellent activity, electrocatalytic properties and excellent stability in alkaline media, which only demands a lower overpotential of 244 mV and 271 mV to deliver a current density of 10 mA cm-2 and 50 mA cm-2, respectively. The material also exhibits excellent stability for at least 24 h during the OER process. This work may provide some new insights into the assembly of advanced and highly-active materials for a variety of other energy conversion applications.
ABSTRACT
A novel LUX (Light Upon eXtension) primer-based real-time PCR assay was developed and evaluated in this study, which was designed to provide a cost-effective, specific and highly sensitive method for viral load determination of hepatitis B virus (HBV). The assay employed an effective and rapid nucleic acid extraction system based on magnetic beads. To evaluate its efficacy, this new viral DNA preparation method was compared with QIAamp Blood Mini Kit and the results showed a good correlation (r=0.971; P<0.001). The performance of the LUX real-time assay was validated by testing serial dilutions of HBV plasmid DNA (5 to 5 x 10(8)copies/reaction) and a good linear relationship was obtained between the Ct values and the log(10) concentration of the HBV DNA. The assay possessed high sensitivity and the detection limit of this system was as few as 25 copies/ml of serum. A total of 91 positive serum samples were detected to evaluate further the assay and the high specificity was confirmed by melting curve analysis. This assay provides an ideal tool for monitoring the treatment efficacy and studying the relationship between HBV viral load and the stage of disease.
