Reduced graphene oxide/zinc oxide composite as an electrochemical sensor for acetylcholine detection

Acetylcholine (ACh) plays a pivotal role as a neurotransmitter, influencing nerve cell communication and overall nervous system health. Imbalances in ACh levels are linked to neurodegenerative diseases, such as Alzheimer's and Parkinson's. This study focused on developing electrochemical sensors for ACh detection, utilizing graphene oxide (GO) and a composite of reduced graphene oxide and zinc oxide (rGO/ZnO). The synthesis involved modified Hummers' and hydrothermal methods, unveiling the formation of rGO through deoxygenation and the integration of nano-sized ZnO particles onto rGO, as demonstrated by XPS and TEM. EIS analysis also revealed the enhancement of electron transfer efficiency in rGO/ZnO. Cyclic voltammograms of the electrode, comprising the rGO/ZnO composite in ACh solutions, demonstrated prominent oxidation and reduction reactions. Notably, the composite exhibited promise for ACh detection due to its sensitivity, low detection threshold, reusability, and selectivity against interfering compounds, specifically glutamate and gamma-aminobutyric acid. The unique properties of rGO, such as high specific surface area and electron mobility, coupled with ZnO's stability and catalytic efficiency, contributed to the composite's potential in electrochemical sensor applications. This research, emphasizing the synthesis, fabrication, and characterization of the rGO/ZnO composite, established itself as a reliable platform for detecting the acetylcholine neurotransmitter.

Crystal Phase Conversion on Cobalt Oxide: Stable Adsorption toward LiO2 for Film-Like Discharge Products Generation in Li-O2 Battery

Regulating the structure and morphology of discharge product is one of the key points for developing high performance Li-O₂ batteries (LOBs). In this study, the reaction mechanism of LOB is successfully controlled by the regulated fine structure of cobalt oxide through tuning the crystallization process. It is demonstrated that the cobalt oxide with lower crystallinity shows stronger affinity toward LiO₂ , inducing the growth of film-like LiO₂ on the electrode surface and inhibiting the further conversion to Li₂ O₂ . The batteries catalyzed by the lower crystallinity cobalt oxide hollow spheres which pyrolyzed from ZIF-67 at 260 °C (ZIF-67-260), go through the generation and decomposition of amorphous film-like LiO₂ , which significantly reduces the charge overpotential and improves the cycle life. By contrast, the ZIF-67 hollow spheres pyrolyzed at 320 °C (ZIF-67-320) with better crystallinity are more likely to go through the solution-mediated mechanism and induce the aggregation of discharge product, resulting in the sluggish kinetics and limited performance. The combined density functional theory data also directly support the strong relationship between the adsorption toward LiO₂ by the electrocatalyst and the battery performance. This work provides an important way for tuning the intermediate and constructing the high-performance battery system.

Popcorn-like Co3O4 Nanoparticles Confined in Three-Dimensional Hierarchical N-doped carbon nanotubes Networks as Highly Efficient Trifunctional Electrocatalyst for Zinc-Air Batteries and Water Splitting Device

A novel unique popcorn-like three-dimensional (3D) hierarchical structural electrocatalyst is synthesized by the pyrolysis of ZIF-8/ZIF-67 and polyacrylonitrile fibers composites, where popcorn-like Co3O4 nanoparticles coated with nitrogen-doped amorphous carbon anchor...

Nanocasting synthesis of an ordered mesoporous CeO2-supported Pt nanocatalyst with enhanced catalytic performance for the reduction of 4-nitrophenol

Ordered mesoporous ceria was used to support Pt nanoparticles stabilized by dendrimers and enhance catalytic reduction of 4-nitrophenol.

Enhanced CO catalytic oxidation of flower-like Co3O4composed of small nanoparticles

The enhanced catalytic performance of flower-like Co₃O₄composed of nanoparticles originates from the redistribution of surface ions induced by the calcining process.

Preparation of platinum nanoparticles immobilized on ordered mesoporous Co3O4–CeO2 composites and their enhanced catalytic activity

Ordered mesoporous Co₃O₄–CeO₂ composites supported uniform Pt nanoparticles and exhibited excellent performance for the reduction of 4-nitrophenol.