Three-dimensional Nanoporous Cu Doped Ni Coating as Bifunctional Electrocatalyst for Hydrazine Sensing and Hydrogen Evolution Reaction.

Developing cost-effective and efficient bifunctional electrocatalyst with simple synthesis strategy for hydrazine sensing and hydrogen evolution reaction (HER) is of utmost importance. Herein, three-dimensional porous Cu doped metallic Ni coating on Ti mesh (Ni(Cu) coating/TM) was successfully electrodeposited by facile electrochemical method. Electrochemical etching of the electrodeposited NiCu coating with metallic Ni and Cu mixed phase on Ti mesh contributed to the formation of three-dimensional porous Cu doped metallic Ni coating. Owing to the large specific surface area and enhanced electroconductivity caused by the porous structure and Cu doping, respectively, the developed Ni(Cu) coating/TM exhibited superior hydrazine sensing performance and electrocatalytic activity toward hydrogen evolution reaction (HER). Ni(Cu) coating/TM electrode presented good sensitivity of 3909 μA mM-1 cm-2 and two relatively broad linear ranges from 0.004 mM to 2.915 mM and from 2.915 mM to 5.691 mM as well as a rather low detection limit (LOD) of 1.90 μM. Besides, Ni(Cu) coating/TM required a relatively low HER overpotential of 140 mV to reach -10 mA/cm2 and exhibited robust durability in alkaline solution. The excellent hydrazine electrooxidation and HER performance guarantee it promising application in hydrazine detection and energy conversion.