C@ZnO nanorod array-based hydrazine electrochemical sensor with improved sensitivity and stability

ZnO nanorod array grown directly on an inert alloy substrate has been modified with carbon by a simple immersion-calcination route and further used as the working electrode to construct a hydrazine sensor. The C@ZnO nanorod array-based sensor demonstrates a very high sensitivity of 9.4 mu A mu M-1 cm(-2) and a low detection limit of 0.1 mu M. The improved electrochemical properties are proposed to result from the synergy between the carbon layer and nanorod array, which can increase the ZnO electrocatalytic activity and promote the electron transport along the one-dimensional (1D) pathway, respectively. In particular, the carbon layer on ZnO nanorods also improves the sensor stability for successive usage due to the high chemical stability of carbon. The present study demonstrates the facile design of a promising electrode material for a hydrazine sensor and sheds light on the performance optimization of other electrochemical devices.