NiO-NiFe2O4/MWCNTs based Electrocatalyst for Electrochemical Water splitting

Abstract

As with drastically increasing energy demands, environmental concerns and scarcity of conventional fossil fuels, there is high need to look for some efficient enough renewable ways for the production of energy which neither are limited by their scarcity nor environmental and global climate change concerns due to the emission of carbon dioxide unlike conventional fossil fuel resources. Hydrogen due to its light weight, high energy density, storage capabilities and environmental friendliness is considered a quite popular fuel. The aim of this study was to produce efficient electrocatalyst for water splitting application. Iron doped Nickel oxide nanoparticles were fabricated recognizing excellent oxygen evolution activity of NiO and conductivity increase with Fe incorporation due to its more electropositivity. Electrocatalysts were synthesized with and without surfactant (Tween 85) and both sample types were calcinated at 600oC, 700oC and 800oC. The synthesized nanoparticles were then deposited on GC (glassy Carbon) electrode to check their activity toward water splitting. Samples synthesized in the presence of Tween turned out to be more efficient due to their smaller particle size and porous structure and hence higher activity. Whereas, samples with 700oC outperformed 600oC and 800oC due to formation of NiO-NiFe2O4 hybrid phase at 700oC temperature. In attempt to futher increase the efficiency and to investigate the effect of MWCNTs incorporation, their nanocomposites with 5%, 10%, 15% and 20% were fabricated with functionalized MWCNTs. Incorporation exhibited significant improvement in activity for 5% and 10 % but at further increase it showed reduction due to filling of pores and reduced percentage of active material (Fe doped NiO). NiO-NiFe2O4/ f-MWCNTs composite (10 weight%, prepared in the presence of surfactant and calcinated at 700oC) outperformed all the other synthesized electrocatalysts in this study with 35mA/cm2 of current density at 1.8V.