HMTA-assisted uniform cobalt ions activated copper oxide microspheres with enhanced electrochemical performance for pseudocapacitors

Superhydrophobic MS@CuO@SA sponge for oil/water separation with excellent durability and reusability

We present a superhydrophobic material based on commercially melamine sponge (MS) with great durability, recyclability, and excellent sorption performance. The fabrication process of this sponge is facile without using toxic reagents or sophisticated equipment and therefore it is simple to scale up. The CuO layer utilized to give a rough surface of the substrate (MS) was successfully prepared in a commercial microwave to seed copper nucleuses in an alkaline medium. Stearic acid (SA) plays a role as the self-assembled monolayer on the surface of the sponge skeletons. Throughout this study, the properties of the modified sponge were fully characterized, and the changes in wettability were carefully examined. Water contact angle (WCA) measurements revealed the excellent superhydrophobicity of the material with high static WCA of 165.1° and low dynamic WCA of 8°. Furthermore, the as-prepared sponge demonstrated high efficiency in separation (over 99.0%) of different oils from water. Notably, several unique properties of as-modified material were found, consisting of ultrafast sorption capacities of up to 32-52 times of its own weight by using 80 mL of each oil, outstanding reusability with good sorption capacity even after 40 cycles. Even under various harsh environments, the novel materials proved its outstanding durability and ultrafast sorption capacity of oils. The durability, recyclability, and superhydrophobic properties of the novel superhydrophobic sponge provide it a solid basis for oil-water separation applications through an ultrafast sorption capacity of oils as well as quick recovery of the oil by easy squeezing process.

Electrochemical Performance of 2D-Hierarchical Sheet-Like ZnCo2O4 Microstructures for Supercapacitor Applications

With the rapid improvement of the global economy, the role of energy has become even more vital in the 21st century. In this regard, energy storage/conversion devices have become a major, worldwide research focus. In response to this, we have prepared two-dimensional (2D)-hierarchical sheet-like ZnCo2O4 microstructures for supercapacitor applications using a simple hydrothermal method. The 2D-hierarchical sheet-like morphologies with large surface area and smaller thickness enhanced the contact area of active material with the electrolyte, which increased the utilization rate. We investigated the electrochemical performance of sheet-like ZnCo2O4 microstructures while using Cyclic voltammetry (CV), Galvanostatic charge-discharge (GCD), and Electrochemical impedance spectroscopy (EIS) analysis. The electrochemical results demonstrated that the ZnCo2O4 electrode possesses 16.13 mF cm−2 of areal capacitance at 10 µA cm−2 of current density and outstanding cycling performance (170% of capacitance is retained after 1000 cycles at 500 µA cm−2). The high areal capacitance and outstanding cycling performance due to the unique sheet-like morphology of the ZnCo2O4 electrode makes it an excellent candidate for supercapacitor applications.