Nickel nanoparticle-decorated reduced graphene oxide/WO nanocomposite - a promising candidate for gas sensing.

We report for the first time the combination of WO sensing elements with a non-noble metal-carbon composite, namely a nickel metal nanoparticle-carbon composite (Ni@rGO). Previous work with WO had used either NiO (as part of the WO lattice), solely carbon, Pd-surface decorated WO (Pd@WO), or Pd or Pt@carbon@WO. We demonstrate the gas response for pure WO, rGO/WO and Ni@rGO/WO sensing elements towards NO and acetone in air as well as towards CO in N. The addition of 0.35 wt % Ni@rGO composite to WO enables the increase of the sensory response by more than 1.6 times for NO vapors. The gas response towards acetone using 0.35 wt % Ni@rGO/WO composite was 1.5 times greater for 3500 ppm than for 35,000 ppm acetone. For 0.35 wt % Ni@rGO/WO composite and CO gas, a response time ( ) of 7 min and a recovery time ( ) of 2 min was determined.