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

Abstract

Self-assembled, aggregated SnWO 4 nano-assemblies are formed by the reaction ofSn(II) salt and Na 2 WO 4 .2H 2 O in the presence of DNA under microwave heating within six minutes. We have emphasized the natural properties of DNA with its ability to scaffold SnWO 4 nano-assemblies and examined the role of starting reagents on the particles morphology. The diameter of the individual particles is ultra-small and varies from ~ 1-2.5 nm. The potentiality of the SnWO 4 nano-assemblies 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 supercapacitor study, it was observed that SnWO 4 nano-assemblies with different sizes showed different specific capacitance (C s ) values and the highest C s value was observed for SnWO 4 nano-assemblies having small size of the individual particles. The highest C s value of 242 F g -1 was observed at a scan rate of 5 mV s -1 for small size SnWO 4 nano-assemblies. The capacitor shows an excellent long cycle life along with 85% retention of C s value even after 4000 consecutive times of cycling at a current density of 10 mAcm -2 . From the catalysis studies, it was observed that SnWO 4 nano-assemblies 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 catalysis and supercapacitor, in futuristic, the material can further be used in sensor, visible light photo-catalysis and energy related applications.Research on nanomaterials, mainly nanoparticles (NPs) has been focused on the assembly strategies to control the specific arrangement of NPs. The morphology controlled synthesis of zero and 1-dimensional (1-D) inorganic nanomaterials have attracted significant interest due to the importance of the geometrical forms of materials in determining their widely varying properties at nanoscale. 1-3 During last few years, a bunch of techniques had been developed for the successful generation of self-assembled NPs into ordered nanostructures. However, there are very few techniques available to organize nanomaterials in a precise 1-D pattern. The 'bottom up' approach and the wet-chemical synthesis have been found to be the most easy and facile way to synthesize self-assemble nanomaterials in 1-D patterns in a short time scale. While considering metal oxide nanomaterials in general, they have been extensively studied owing to their unique magnetic, catalytic and Energy storage properties across a broad range of fundamental and technological potential. In particular, the fields like Energy storage and in catalysis. Electrochemical Supercapacitors show the desirable characteristics of high power density, fast charging, excellent cyclic stability, small size and low mass, when compared with batteries and fuel cells, make them one of the most promising candidates for next generation power devices. 4-7 In general, most commercially available ...

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Review on Recent Progress in the Development of Tungsten Oxide Based Electrodes for Electrochemical Energy Storage

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