Abstract
This study reports a scalable green electrochemical synthesis of novel biogenic silver nanoparticles colloid (biogenic AgNPs) in large scale up to 5 liters using the bulk silver bar and the green tea leaves (Camellia sinensis) extract (GTE) as reducing agent during the electrochemical process. Under a direct-current voltage source, the biomolecules in GTE can release electrons to promote the reducing process of Ag+ to Ag0. More interestingly, the formation of the intermediate complex helps to cap on the nanoparticles, which leads to stabilizing AgNPs. The as-synthesized biogenic AgNPs with the size of 34 nm exhibit the outstanding electrochemical properties due to the presence of biomolecules on the biogenic AgNPs surface, which facilitates the effective attaching of AgNPs on the carbon surface of the screen-printed carbon electrode (SPE) through the formation of the strong C-O coordinate bonds between O atom of oxygen functional groups and C atom of SPE. The electrochemical properties of the biogenic AgNPs-modified SPE are enhanced significantly in comparison with bare SPE and pure AgNPs-SPE. The biogenic AgNPs-SPE is applied successfully to the detection of 4-nitrophenol (4-NP). The electrochemical sensor using biogenic AgNPs can reliably detect 4-NP in the linear range from 0.1 to 25 μM with the sensitivity about 6.69 μA μM-1 cm-2. The present work reveals, as the greener synthesis method with ultra-large scalable ability, high purity, and excellent electrochemical properties of biogenic AgNPs is very promising for technological applications in high-sensitive electrochemical chemosensors, nanopharmaceuticals, and other fields.
Highlights
AgNPs are one of the nanomaterials possessing the highest degree of commercialization owing to the full range of potential applications in sensors, biomedical imaging, disinfection agents, healthcare products, cleaning agents, food storage, textile coatings, and medical devices [1,2,3]
Based on the advantages and disadvantages of both biosynthesis method and electrochemical method, in this work, we propose a scalable green electrochemical process to rapidly synthesize biogenic AgNPs in large scale up to 5 liters using the bulk silver bar and the GTE as reducing agent to replace metal salts in the normal electrochemical method which is aimed at promoting synthetic efficiency in the short time and safety of the product
It is noted that the absorption band was shifted to longer wavelengths for biogenic AgNPs synthesized at 14 V as compared to the sample at 12 V
Summary
AgNPs are one of the nanomaterials possessing the highest degree of commercialization owing to the full range of potential applications in sensors, biomedical imaging, disinfection agents, healthcare products, cleaning agents, food storage, textile coatings, and medical devices [1,2,3]. The electrochemical method has been recently considered as a promising approach for the straightforward synthesis of pure AgNPs with high quality, large scale, and low cost [6, 7] In this technique, the bulk silver electrodes are the major pure precursor for the formation of AgNPs. A bulk silver electrode is anodically dissolved to create Ag+, and they are reduced to Ag0 under the presence of metal salts in the electrolyte at the cathode. Based on the advantages and disadvantages of both biosynthesis method and electrochemical method, in this work, we propose a scalable green electrochemical process to rapidly synthesize biogenic AgNPs in large scale up to 5 liters using the bulk silver bar and the GTE as reducing agent to replace metal salts in the normal electrochemical method which is aimed at promoting synthetic efficiency in the short time and safety of the product. The formation mechanism and excellent electrochemical properties of biogenic AgNPs have been discussed in detail
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