Nickel nanoparticle-decorated reduced graphene oxide/WO ₃ nanocomposite – a promising candidate for gas sensing

We report for the first time the combination of WO ₃ sensing elements with a non-noble metal–carbon composite, namely a nickel metal nanoparticle–carbon composite (Ni@rGO). Previous work with WO ₃ had used either NiO (as part of the WO ₃ lattice), solely carbon, Pd-surface decorated WO ₃ (Pd@WO ₃ ), or Pd or Pt@carbon@WO ₃ . We demonstrate the gas response for pure WO ₃ , rGO/WO ₃ and Ni@rGO/WO ₃ sensing elements towards NO ₂ and acetone in air as well as towards CO in N ₂ . The addition of 0.35 wt % Ni@rGO composite to WO ₃ enables the increase of the sensory response by more than 1.6 times for NO ₂ vapors. The gas response towards acetone using 0.35 wt % Ni@rGO/WO ₃ composite was 1.5 times greater for 3500 ppm than for 35,000 ppm acetone. For 0.35 wt % Ni@rGO/WO ₃ composite and CO gas, a response time ( T _res ) of 7 min and a recovery time ( T _rec ) of 2 min was determined.