Silver/diamond powder (Ag/DP) composites have been prepared via pyrolysis of silver nitrate (AgNO3) on silicon substrate. Fourier Transform Infrared (FTIR) Spectra shows that the infrared absorption of nitrate (NO3-) is enhanced by the as-grown composites and increased further by the employment of an external electric field, which not only makes the Ag/DP composites improve the NO3- vibration strength considerably, but also induces significant differences in absorption intensity and frequency between the two individual antisymmetric stretching modes of NO3-. These features will expand the reach of infrared spectroscopy to a new class of nitrate salt detections. (C) 2014 Elsevier B.V. All rights reserved.