Hafnium Oxide/Graphene Oxide Nanocomposites as Efficient Supercapacitor Electrodes

Abstract

This paper reports on the preparation of graphene oxide (GO) modified with hafnium oxide (HO) nanoparticles composites by a simple mixing and their use as efficient electrode in electrochemical supercapacitors. The technique relies on simple mixing the aqueous solutions of hafnium oxide (HO) nanoparticles and graphene oxide (GO) at different ratios of GO content (20, 30 and 40 wt%). The morphological studies, chemical composition and electrochemical behavior of the resulting HO/GO nanocomposites were investigated by using UV/vis spectrometry, X-Ray Diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electrochemical respectively. The electrochemical performance, including the capacitive behavior of the HO/GO nanocomposites were investigated by cyclic voltammetry and galvanostatic charge-discharge curves. The HO/GO nanocomposites (40 wt%) ratio exhibited the best performance with a specific capacitance of 268 Fg -1 at a scan rate 5 mVs -1 in 1 M H2SO4 and it shows excellent long-term cycle stability.

Superhydrophobic Copper‐Composite Surfaces Exert Antibacterial Effects against Gram‐Negative and ‐Positive Bacteria

“…HfO 2 ‐based nanoparticles have been reported to show antibacterial activity against certain Gram‐negative bacteria, such as Klebsiella pneumoniae and S. aureus . [ 66 ] Here, SHB nano‐HfO 2 showed moderate to high binding affinity toward each bacteria, with Pa_15442 and Pa_9027 showing the greatest adherence. Other studies have indicated the ability of HfO 2 nanopores/nanofilms to bind proteins and DNA, [ 8,67 ] implying that the fabricated HfO 2 –PDMS exhibited positively charged surface under the experimental conditions used and thus could have stimulated the bacterial adherence to this material.…”

Gram-scale synthesis of highly biocompatible and intravenous injectable hafnium oxide nanocrystal with enhanced radiotherapy efficacy for cancer theranostic

“…However, the synthesized HfO2 NPs seem to exhibit poor monodispersity, which are not suitable for via i.v. injection [24][25][26]. Other the available preparation method for uniform HfO2 NPs are harsh, such as in the condition of anhydrous and anaerobic [27].…”

Synthesis and Characterization of Functionalized Hafnium Oxide Nanoparticles for Supercapacitor Applications

“…Like aforesaid series, hafnium oxide (HfO 2 ) is also one of the metal oxides in transition metals and it offers a lower cost, less toxic and its availability creates us more interest. Consequently, expectation of nanosized HfO 2 particles towards supercapacitor performance has increased [13] and addition of oxides can improve the cycling stability of energy storage devices (ESD) [14][15][16]. But, functionalization and dispersion of metal oxide are of crucial importance for their applications, as they have enormous utilization in several areas including defense, aerospace, electric vehicles and consumer electronics applications [17].…”