Copper (II) oxide nanowires for p-type conductometric NH3 sensing

Abstract

Copper (II) oxide (CuO) is a metal oxide suitable for developing solid state gas sensors.Nevertheless, a detailed insight into the chemical-to-electrical transduction mechanisms between gas molecules and this metal oxide is still limited. Here, individual CuO nanowires were evaluated as ammonia (NH 3 ) and hydrogen sulphide (H 2 S) sensors, validating the p-type character of this semiconductor. The working principle behind their performance was qualitatively modelled and it was concluded that adsorbed oxygen at the surface plays a key role necessary to explain the experimental data. Compared to their counterparts of SnO 2 nanowires, an appreciable sensitivity enhancement to NH 3 for concentrations below 100 ppm was demonstrated.

Room-Temperature High-Performance H2S Sensor Based on Porous CuO Nanosheets Prepared by Hydrothermal Method

“…The porous structure is obviously different from the literature for those leaves-like or sheet structures of CuO. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] The surface area of these CuO nanosheets obtained based on the BET method is 10.03 m 2 ·g -1 . These porous CuO nanosheets are efficient for the gas flowing in and out, thus enhancing their gas sensing performance.…”

“…However, the similar reaction on the CuO materials and the associated changes in the resistance are also commonly observed in absorption of other types of reducing gases, including CO, 11,30 alcohol, 31,32 methane and ammonia gases. 33,34 Therefore, the specific H 2 S sensors with a good selectivity should be explored.…”

Facile synthesis of 3D CuO nanowire bundle and its excellent gas sensing and electrochemical sensing properties

“…Irregular shape of particles or mixtures containing microspheres or nanorods were formed under heating (hydrothermal, microwave or ultrasonic). This may be because the reaction rate is 4 2− ion due to electrostatic interactions between Cu 2+ central ion and the two anions (Scheme 1a). This inhibits the growth of the product along the direction perpendicular to the square in an octahedron (vertical direction).…”

“…Copper oxide is a well-known p-type semiconductor with a narrow band gap of 1.2 eV and has been extensively studied because of its versatile applications, such as catalysts [1], magnetic storage media [2], gas sensors [3][4][5], lithium batteries [6], amperometric sensors [7][8][9], etc. Because the practical performances of CuO nanomaterials are close related to its morphology and size, which ultimately depends on the preparation methods and reaction conditions [10,11], various methods have been developed to synthesize CuO nanostructures, for example, thermal oxidation of copper foil, hydrothermal route, vapor-liquid-solid synthesis, ultrasound irradiation, thermal decomposition of precursors, electron beam lithography, etc.…”

Preparation of gas sensing CoTiO3 nanocrystallites using EDTA as the chelating agent in a sol–gel process

“…On the other hand, as the temperature increases further, the gas adsorption is too difficult to be adequately compensated for the increased surface reactivity. This might be due to the increase of desorption kinetics on the surface of the sensor material [27]. Therefore, the response decreases when the operating temperature is higher than 310 1C.…”