High selectivity trimethylamine sensors based on graphene-NiGa2O4 nanocomposites prepared by hydrothermal method

In this paper, a series of graphene (G)-NiGa2O4 nanocomposites were prepared by hydrothermal method. The as-prepared nanocomposites were characterized by XRD, SEM, HRTEM, FTIR, Raman, XPS and nitrogen adsorptiondesorption, respectively. The effect of the amount of graphene in the nanocomposites on the gas sensing responses and gas sensing selectivity of G-NiGa2O4 nanocomposites was investigated. It was found that the addition of graphene in nanocomposites increased the responses of nanocomposites to trimethylamine (TMA) when operating at 20 degrees C and 2 wt% G-NiGa2O4 nanocomposite showed the best gas sensing performances among all studied nanocomposites. 2 wt% G-NiGa2O4 nanocomposite exhibited high gas sensing selectivity to TMA at room temperature, the ratio of S (1000 )(ppm)( TMA)/S (1000 )(ppm) ammonia reached 36.1; the detection limit for TMA reached 0.01 ppm, the response time and recovery time for 0.01 ppm TMA were 13 and 2 s, respectively.