A novel nano-Au-assembled gas sensor for atmospheric oxygen determination

Abstract

A novel nano-Au-assembled gas sensor was fabricated and first used to determine atmospheric oxygen. The special characteristics of nano-Au resulted in a high catalytic activity for the reduction of oxygen. On determining 20.9% oxygen by cyclic voltammetry, on a nano-Au-assembled Pt disk electrode the overpotential decreased greatly and the reduction current of oxygen increased to about 4.4 times that on a bare gas sensor. For the determination of atmospheric oxygen by using this novel nano-Au-assembled gas sensor with the amperometric i–t curve method, the linear range was from 0.4 to 30.0%, the linear equation was y = 1.11x − 0.63 with a correlation coefficient of 0.9931, the sensitivity was 1.11 × 10⁻⁷ A cm⁻² per 1% v/v, the detection limit was 0.2%, the response time was about 12 s and the relative standard deviation was 2.9% on determining the background value of atmospheric oxygen. It was also found that the nano-Au-assembled gas sensor had good reproducibility and stability. These results demonstrated that this sensor for the determination of atmospheric oxygen was fast, sensitive, accurate and convenient.