Electrocatalytic oxidation of methanol by ZSM-5 nanozeolite-modified carbon paste electrode in alkaline medium

Boosting the Electrochemical Oxygen Evolution with Nickel Oxide Nanoparticle-Modified Glassy Carbon Electrodes in Alkaline Solutions

The present work investigates the electrocatalysis of oxygen evolution (OE) on a glassy carbon electrode modified with nickel oxide nanoparticles (NPs) (nano-Ni) in an alkaline solution. The nano-Ni is electrodeposited from an acidic sulfate electrolyte containing various additives, such as glucose, glycerol, and dimethyl glyoxime. The NPs are characterized morphologically and electrochemically using scanning electron microscopy and cyclic voltammetry. The elemental composition and electronic state of the modified electrodes were analyzed using X-ray photoelectron spectroscopy. A considerable enhancement in electrocatalytic activity, depending on the additives used, is observed. The study also explores the effect of nickel oxide loading to optimize the process. The highest cathodic shift in the onset potential of the oxygen evolution reaction is achieved with nickel oxide deposited in the presence of ethylene glycol.

Synthesis of chitosan-grafted poly-acrylic acid (CTS-g-PAA) hydrogel and its potential application in biosensors for signal enhancing and bioanalysis

Nowadays, hydrogels have been attracted a lot of interest due to their immense potential in different fields such as biomedicine and biotechnology. Biodegradable and biocompatible pH-sensitive chitosan-grafted polyacrylic acid (CTS-g-PAA) hydrogel was synthesized by grafting an acrylic acid monomer onto chitosan at the presence of methylene bisacrylamide as a cross-linking agent and ammonium persulphate as an initiator. FT-IR spectroscopy and scanning electron microscopy (SEM) were used to analyze the properties of the obtained hydrogel. The synthesized hydrogel is suitable for the delivery of many hydrophilic drugs or species. Using a multi-walled carbon nanotube modified-glassy carbon electrode (CNT-GCE), the loading and release conditions of Nile Blue (NB) as an electroactive compound were evaluated utilizing the differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The effect of various parameters on the electrochemical signal of NB was investigated, and the optimal conditions for the efficient performance of hydrogel to delivery of NB were obtained. The electrocatalytic current values show linear dependence to NB concentration in the range of 0.098 - 0.971 μM while the detection limit of this electrochemical platform was 12.3 nM. The unique proposed hydrogel with the electroactive NB has a broad range of possible applications in biosensors for signal enhancement and bioanalysis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10854-021-06939-7.

Fabrication of a non-enzymatic Ni(ii) loaded ZSM-5 nanozeolite and multi-walled carbon nanotubes paste electrode as a glucose electrochemical sensor

A template-free ZSM-5 nanozeolite was synthesized and then carbon paste electrode (CPE) was modified by ZSM-5 nanozeolite, multi-walled carbon nanotubes and Ni²⁺ and was used as catalyst for the electrooxidation of glucose (EC′ mechanism).