Acetone sensing and modelling by low-cost NiO nanowalls

NiO nanowalls were grown by low-cost chemical bath deposition (CBD) method and thermal annealing. SEM analysis showed a high surface area and porous thin film formed by a network of similar to 20 nm thick and similar to 270 nm tall nanosheets. NiO nanowalls were prepared onto interdigitated electrodes and applied for acetone sensing. The response transients at various temperatures were recorded an successfully modelled by two adsorption sites. Both sites are active below 250 degrees C, while only the site with shorter response time is active above 250 degrees C. At the optimal temperature of 250 degrees C, the sensor demonstrated high sensitivity to acetone (1-40 ppm), a low limit of detection (LoD) of similar to 200 ppb and good selectivity. These unique features combined with the low-cost and simple fabrication process make it a cheap and efficient acetone sensor. (C) 2019 Elsevier B.V. All rights reserved.