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Oxygen reduction reaction (ORR),as a multielectron electrode reaction, is an important electrochemical reaction in the field of electrochemical energy storage systems. Herein, a new advanced electrochemical laboratory experiment is designed for undergraduates to master the preparation of oxygen reduction catalytic electrode. Students can use rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) to evaluate the properties of the ORR catalyst and expound the kinetics mechanism of multielectron electrode reaction. By fitting the K-L curve to calculate the electron transfer number, the ORR reaction path of the industrial Pt/C catalyst in the KOH electrolyte can be determined. The basic kinetic parameters of the ORR and the intermediate content will help students to deeply understand the Butler-Volmer equation. The new teaching experiment focuses on the integration of frontier scientific research and undergraduate teaching. This experiment may enhance students' interest in learning electrochemistry and broadening their horizons as well as help them understand the ORR mechanism involved in modern electrochemical testing technology. In addition, the student's ability of data processing and comprehensive analysis will be improved. This new comprehensive experiment is a fundamental, innovative, and systematic physical chemistry experiment.

The development of an electrochemical energy storage system with exceptional performance is an important way to address the energy crisis and environmental pollution of the modem world. In this study, an NiCo2O4@MnS composite with a unique hierarchical structure has been successfully synthesized on an NF substrate using the hydrothermal–electrodeposition method. The results indicate that NiCo2O4@MnS possesses superior specific capacitance and excellent cycling stability. At a current density of 2 A g−1, its specific capacitance can reach 2100 F g−1, while the capacitance retention is still 76% after 10 000 cycles at 10 A g−1. Moreover, when the current density is 1 A g−1, the assembled NiCo2O4@MnS//AC device can deliver a specific capacitance of 203 F g−1, and the energy density is up to 55 W h kg−1 at a power density of 697 W kg−1. These outstanding electrochemical properties of NiCo2O4@MnS can be ascribed to the increase in ion diffusion, specific surface area and electronic conductivity due to its unique hierarchical structure and introduction of MnS. [ABSTRACT FROM AUTHOR]

A NiB binary catalyst with a unique mulberry-like nanoparticle morphology has been prepared by one-step electrodeposition. The NiB-0.2 catalyst exhibits excellent catalytic activity, selectivity, and stability for the borohydride oxidation reaction. Moreover, a direct borohydride fuel cell using the NiB-0.2 catalyst anode can deliver a peak power density of 453 mW cm−2 and open-circuit voltage of 1.96 V at 343 K. The improved performances are due to the introduction of B. This study may inspire the development of efficient noble-metal-free anode catalysts for DBFCs. [ABSTRACT FROM AUTHOR]

Developing catalysts with superior activity to hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is equally important to the overall photoelectrochemical water splitting to produce hydrogen. In this work, bismuth oxyiodide (BiOI), iron-modified bismuth iodide Fe/BiOI, and the sulfurized S-Fe/BiOI were prepared using the solvothermal method. The three materials all have good absorption ability for visible light. The photoelectrochemical catalytic activity of BiOI to oxygen evolution reaction (OER) is significantly enhanced after iron modification, while the sulfurized product S-Fe/BiOI exhibits better catalytic activity to hydrogen evolution reaction (HER). Hence, OER and HER can be simultaneously catalyzed by using Fe/BiOI and S-Fe/BiOI as anodic and cathodic catalysts to facilitate the overall photoelectrochemical water splitting process. [ABSTRACT FROM AUTHOR]

This paper is concerned with the global existence and large-time behavior of strong solutions to an initial boundary value problem of the one-dimensional isentropic compressible Navier-Stokes equations with degenerate density-dependent viscosity on the half line $ \mathbb{R}^+ = (0,+\infty) $. We focus on the impermeable wall problem where the velocity $ u(t,x) $ of the fluid is zero on the boundary $ x = 0 $. The case when the pressure $ p(v) = v^{-\gamma} $ and the viscosity coefficient $ \mu(v) = v^{-\alpha} $ for the specific volume $ v(t,x)>0 $ is considered, where $ \alpha,\gamma\in \mathbb{R} $ are some parameters. Under some suitable assumptions on the parameters $ \alpha,\gamma $ and the initial data, we prove that the impermeable wall problem of the one-dimensional compressible Navier-Stokes equations admits a unique global strong non-vacuum solution, which tends to the constant equilibrium state as time goes to infinity. Here the initial perturbation can be arbitrarily large. Our analysis is based on a new approach to derive the uniform-in-time positive lower and upper bounds on the specific volume and delicate estimates to control the boundary terms. [ABSTRACT FROM AUTHOR]