Implication of potassium trimolybdate nanowires as highly sensitive and selective ammonia sensor at room temperature

Abstract

Potassium trimolybdate nanowires are demonstrated as unique and highly selective NH3 sensing materials at room temperature. The nanowires were synthesized by using chemical route under normal ambient conditions and subsequently characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Gas sensors based on nanowires were fabricated by isolating and aligning nanowires between microspaced electrodes using dielectrophoresis. Room temperature gas sensing studies for different vapors indicated excellent selectivity for NH3 and capability to detect NH3 at concentrations down to ppb level. The sensors exhibited higher sensitivity for concentration range much below toxic limit of NH3 from 500 ppb up to 25 ppm. Since nanowires are isolated and aligned, the gas sensing reaction is rapid, and the availability of abundant oxide and hydroxyl surface groups on nanowires surface makes the reaction significantly prominent and selective with highly reducing nature of NH3.