Is the Plastic Pandemic a Greater Threat to Humankind than COVID-19?

The advent of the COVID-19 pandemic has initiated a radical attention shift of society toward the severe consequences it has had over human health, shadowing a symmetrically, if not more, important issue of the rapid intensification in the amount of plastic waste that has been generated over the due course of time. Such a growth in the plastic footprint across the globe has led to a carbon positive environment with an increased amount of greenhouse gases (GHGs) released due to the processing of the waste plastic. We aim to address and provide our perception to this pressing challenge that can be decoded via the advancement of upcycling technologies, utilized and augmented worldwide. With the establishment of such sustainable policies and strategies, the global plastic footprint can be systematically mitigated, accelerating the world into economic circularity and environmental sustainability.

Double transition metal MXene (TixTa4-xC3) 2D materials as anodes for Li-ion batteries.

A bi-metallic titanium-tantalum carbide MXene, TixTa(4-x)C3 is successfully prepared via etching of Al atoms from parent TixTa(4-x)AlC3 MAX phase for the first time. X-ray diffractometer and Raman spectroscopic analysis proved the crystalline phase evolution from the MAX phase to the lamellar MXene arrangements. Also, the X-ray photoelectron spectroscopy (XPS) study confirmed that the synthesized MXene is free from Al after hydro fluoric acid (HF) etching process as well as partial oxidation of Ti and Ta. Moreover, the FE-SEM and TEM characterizations demonstrate the exfoliation process tailored by the TixTa(4-x)C3 MXene after the Al atoms from its corresponding MAX TixTa(4-x)AlC3 phase, promoting its structural delamination with an expanded interlayer d-spacing, which can allow an effective reversible Li-ion storage. The lamellar TixTa(4-x)C3 MXene demonstrated a reversible specific discharge capacity of 459 mAhg-1 at an applied C-rate of 0.5 °C with a capacity retention of 97% over 200 cycles. An excellent electrochemical redox performance is attributed to the formation of a stable, promising bi-metallic MXene material, which stores Li-ions on the surface of its layers. Furthermore, the TixTa(4-x)C3 MXene anode demonstrate a high rate capability as a result of its good electron and Li-ion transport, suggesting that it is a promising candidate as Li-ion anode material.

Reversible, stable Li-ion storage in 2 D single crystal orthorhombic α-MoO3 anodes.

Engineering two dimensional (2D) materials at atomic level is a key factor to achieve enhanced electrochemical Li-ion storage properties. This work demonstrates that single crystals of orthorhombic α-MoO3 phase can preferentially grow with a 2D nanoarchitecture via a ball-milling process, followed by heat treatment at elevated temperature. Detailed FE-SEM and TEM micrographs proved the 2D architecture of α-MoO3 nanoparticles and Raman spectroscopy evidenced the active vibration modes that correspond to the orthorhombic α-MoO3 phase. Single crystalline MoO3 belts depicted high intensity of (0 2 0) and (0 4 0) indexed planes indicating a preferential arrangement. As Li-ion host anode, the 2D α-MoO3 nanostructure delivered high reversible specific discharge capacity of ~540 mA h g-1 at 0.2 C-rate with 99.9% coulombic efficiency as well as 63% capacity retention after 200 charge-discharge cycles. An excellent reversible Li-ion storage performance (high capacity, longer cycle life and good rate capability) was attributed to the 2D α-MoO3 arrangement consists of MoO6 octahedron by corner sharing chains.