A Unique Hierarchical Structure: NiCo2O4 Nanowire Decorated NiO Nanosheets as a Carbon-Free Cathode for Li–O2 Battery

The development of high-performance cathodes is critical to promoting the development of Li-O2 batteries. In this work, three-dimensional NiCo2O4 nanowire-decorated NiO nanosheets (NiO@NiCo2O4) on a Ni foam were fabricated...

Symmetric Catalytic Pt-MnO2@Carbon Microspheres as Micromotors for Dynamic Pollutant Remediation

Organic pollutants in water pose a serious risk to public health, hence, it is essential to develop new and innovative approaches to the remediation of contaminated water. This work demonstrates a highly effective bubble-propelled micromotor based on the surface coating of symmetrical carbon microspheres (CMSs) with catalytic manganese dioxide (MnO2) nanoflakes and platinum nanoparticles (Pt NPs) (Pt-MnO2@CMS). This concept represents a simple and flexible strategy for the decomposition of organic pollutants in water and could be used to construct a wide range of diverse micromotors with applications in drug delivery, sensing, energy generation and environmental remediation. The unique hierarchical structure of the MnO2 nanoflakes and the uniform dispersion of Pt NPs in this material were confirmed. The resulting micromotors were found to move rapidly as a result of propulsion by oxygen bubbles generated in a H2O2 solution via the catalytic actions of the MnO2 nanoflakes and Pt NPs. In contrast to the intrinsic asymmetry of tubular and Janus structures, the self-driven motion of these symmetrical micromotors can be attributed to morphological variations and the uneven distribution of the cocatalysts. Combining a porous structure, rapid movement and Fenton-like reactions, these Pt-MnO2@CMS micromotors rapidly degraded methylene blue (MB), providing greater than 99% decolorization in just 30[Formula: see text]min without the need for external agitation. Analyses of the adsorption mechanism based on pseudo-first-order and pseudo-second-order kinetics models showed that adsorption proceeded via chemical processes. These new micromotors are expected to have important environmental and biomedical applications.

Facile Synthesis of Hierarchical CuO Microspheres and their Gas Sensing Properties for NOx at Room Temperature

In this research, hierarchical CuO microspheres have been successfully synthesised by a facile reflux method. Scanning electron microscopy results clearly revealed that the hierarchical CuO microspheres were composed of two-dimensional nanosheets. The morphology of the prepared products could be tailored by changing the precursor concentration. The CuO-2 sample shows a higher NOx gas sensing performance with a low detection limit of 0.97 ppm, high gas response of 64.93 %, and short response time of 5.33 s to 97.0 ppm NOx at room temperature. The CuO-2 sensor also presents good selectivity and stability. The significantly improved gas response was concluded to be related to the well aligned microstructures and the improved conductivity of the CuO-2 sample. The unique hierarchical structure allows effective and rapid gas diffusion towards the sensing surfaces. In addition, the sensing mechanism based on the hierarchical CuO microspheres is discussed.

One-pot hydrothermal synthesis of peony-like Ag/Ag0.68V2O5 hybrid as high-performance anode and cathode materials for rechargeable lithium batteries

We proposed a simple but effective method to synthesize a peony-like Ag/Ag0.68V2O5 hybrid and explored the effects of its unique hierarchical structure on the superior cycling stability as electrode material for rechargeable lithium batteries.