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Microwave Synthesis of SnWO4 Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation

Ede, Sivasankara Rao, Kundu, Subrata
ACS sustainable chemistry 2015 v.3 no.9 pp. 2321-2336
DNA, anodes, butanol, capacitance, catalysts, electrical equipment, electrochemistry, energy, hydrogen peroxide, microwave treatment, oxidants, oxidation, photocatalysis, tin
Self-assembled, aggregated SnWO₄ nanoassemblies are formed by the reaction of Sn(II) salt and Na₂WO₄·2H₂O in the presence of DNA under microwave heating within 6 min. We have emphasized the natural properties of DNA with its ability to scaffold SnWO₄ nanoassemblies and examined the role of starting reagents on the particles’ morphology. The diameter of the individual particles is ultrasmall and varies from ∼1–2.5 nm. The potentiality of the SnWO₄ nanoassemblies has been tested for the first time in two different applications, such as an anode material in electrochemical supercapacitor studies and as a catalyst for the oxidation of butanol to butanoic acid. From the supercapacitor study, it was observed that SnWO₄ nanoassemblies with different sizes showed different specific capacitance (Cₛ) values and the highest Cₛ value was observed for SnWO₄ nanoassemblies having small size of the individual particles. The highest Cₛ value of 242 F g–¹ was observed at a scan rate of 5 mV s–¹ for small size SnWO₄ nanoassemblies. The capacitor shows an excellent long cycle life along with 85% retention of Cₛ value even after 4000 consecutive times of cycling at a current density of 10 mA cm–². From the catalysis studies, it was observed that SnWO₄ nanoassemblies acted as a potential catalyst for the oxidation of butanol to butanoic acid using eco-friendly hydrogen peroxide as an oxidant with 100% product selectivity. Other than in catalysis and supercapacitors, in the future, the material can further be used in sensors, visible light photocatalysis and energy related applications.