Ni3S2@Ni foam 3D electrode prepared via chemical corrosion by sodium sulfide and using in hydrazine electro-oxidation

Abstract

Hydrazine electro-oxidation takes an important role in direct hydrazine fuel cells (DHFCs) and hydrazine electrochemical sensor, but the high cost of precious metal electrode hinders the practical applications of hydrazine electro-oxidation. In this study, an inexpensive 3D electrode of Ni3S2@Ni foam was obtained through a hydrothermal condition using sodium sulfide as corrodent and Ni foam as both substrate and Ni source. The formation mechanism of this Ni3S2 layer was studied through a process analysis based on physical chemistry with assistant of the results from characterizations. The obtained Ni3S2@Ni foam was used as electrode to test its hydrazine electro-oxidation properties in terms of DHFCs and electrochemical sensor. It is found Ni3S2@Ni foam possesses the ability to electro-oxidize hydrazine and Ni3S2 layer leads to increased activity including lower onset potential and higher current. In the aspect of hydrazine electrochemical sensor, the fabricated Ni3S2 layer leads to increased sensitivity and dynamic response property. The results indicate that as-prepared Ni3S2@Ni foam possesses a potential for practical application in hydrazine electro-oxidation, and Ni3S2 is a very promising substitute material for noble metals in hydrazine electro-oxidation. At the same time, with the characterization of the as-prepared Ni3S2@Ni foam electrode on structure, morphology and surface chemical states, the mechanism of the corrosion method as well as enhanced properties were investigated.