Electrophoretic fabrication of ZnO/ZnO-CuO composite for ammonia gas sensing

Abstract

Nanostructured deposits of ammonia (NH 3 ) sensitive ZnO and ZnO-CuO composites were fabricated on a graphite electrode via electrophoretic deposition (EPD). Deposition was done by holding the applied voltage and deposition time constant at room temperature. Testing of sensing properties of the deposits was conducted using Wheatstone bridge circuit. SEM micrographs show a more open structure and more exposed surface area of the pure ZnO deposit compared to the ZnO-CuO deposit. The average particle size deposited at 500V for ZnO and ZnO-CuO were 241nm and 260nm respectively; whereas at 750V the average particle size is 195nm and 276nm, respectively. Deposits with greater surface area, smaller particle sizes and thicker deposits exhibit high gas sensitivity. On the other hand, addition of CuO resulted to a more compact and dense surface structure and decreased gas sensitivity. Thus, particle size and the surface structure of the deposits dictate the sensitivity of the material.

Nanoporous hybrid CuO/ZnO/carbon papers used as ultrasensitive non-enzymatic electrochemical sensors

“…13,14 The heterostructured ZnO-CuO composite material has been extensively used for non-enzymatic sensing applications due to the extension of its electron depletion layer through the formation of a p-n junction. 11,12 Therefore, a number of studies have been devoted to the synthesis of CuO-ZnO hybrid materials, [12][13][14][15][16][17][18] such as three-dimensional porous ZnO-CuO hierarchical nanocomposites fabricated by coelectrospinning 19 and ower-like CuO-ZnO heterostructured nanowire arrays on a mesh substrate obtained using a solution method. 20 Among them, 0D nanoparticles or 1D nanowires have been dominant for a long period.…”

Defect-Induced Phase Transformations in CuO Thin Films by Ag Ion Implantation and Their Gas-Sensing Applications

“…Significant work has been done on chemically doped CuO thin films to modify their physical properties. Various dopants such as Mn, Fe, Zn, Ag, Ni, Ti Li, − and In are added to CuO thin films using chemical methods. However, this method suffers from some serious drawbacks as the physical properties of the material cannot be modified in a controlled manner as can be done through the ion implantation technique.…”

Nitrogen Oxide (NO) Gas-Sensing Properties of Bi2MoO6 Nanosheets Synthesized by a Hydrothermal Method

“…4 Chemiresistive gas sensors based on metal oxides are the most potential candidates because of their advantageous features such as low cost, fast response/recovery time and high compatibility with microelectronic processing. [5][6][7][8][9] Recently, with the fast development of nanotechnology, a large number of nanostructured materials including SnO 2 , WO 3 , ZnO, Co 3 O 4 , and La 2 O 3 have been employed for gassensing applications. 10 However, compared to these simple binary oxides, multicomponent oxides have greater advantages.…”