Electrosynthesis and characterization of gold nanoparticles for electronic capacitance sensing of pollutants

Abstract

In the present study, gold/surfactant core/shell colloidal nanoparticles with a controlled morphology and chemical composition have been obtained via the so-called sacrificial anode technique, carried out in galvanostatic mode. As synthesized Au-NPs had an average core diameter comprised between 4 and 8 nm, as a function of the electrochemical process experimental conditions. The UVVis characterization of gold nanocolloids showed clear spectroscopic size effects, affecting both the position and width of the nanoparticle surface plasmon resonance peak.The nanomaterial surface spectroscopic characterization showed the presence of two chemical states, namely nanostructured Au (0) (its abundance being higher than 90%) and Au (I) . Au-NPs were then deposited on the top of a capacitive Field Effect sensor and subjected to a mild thermal annealing aiming at removing the excess of stabilizing surfactant molecules. Au-NP sensors were tested towards some gases found in automotive gas exhausts. The sensing device showed the largest response towards NO x , and much smaller -if any-responses towards interferent species such as NH 3 , H 2 , CO, and hydrocarbons.

Electrosynthesis and characterization of ZnO nanoparticles as inorganic component in organic thin-film transistor active layers

“…In this field, a pioneering paper on sizeselective synthesis of colloidal core-shell metal nanoclusters (Pd, Ni, etc.) by a pure electrochemical method was proposed by the group of Reetz more than twenty years ago [31], which produced a cascade of subsequent studies [32][33][34]. Therein, an electrolyte composed of acetonitrile and tetrahydrofuran (ACN/THF 4:1) in the presence of tetraoctylammonium bromide (TOAB) as capping agent was used applying a moderate current density of 0.1 mA/cm 2 .…”

Electrochemical deposition of gold on indium zirconate (InZrOx with In/Zr atomic ratio 1.0) for high temperature automobile exhaust gas sensors

“…Moreover, it has already been established that Au nanoparticles' size distribution range is narrow depending upon the nature of surfactant [41]. Herein, Au nanoparticles deposited on the surface of InZrOx can be clearly observed in Fig.…”

Electrophoretic deposition of Au NPs on MWCNT-based gas sensor for tailored gas detection with enhanced sensing properties

“…The colloidal solution containing Au NPs, used to directly decorate MWCNT-based gas sensors, was prepared by the sacrificial anode electrolysis (SAE), as described elsewhere [43]. The electrochemically synthesized Au NPs have a uniform dispersion with diameter of 12 nm ± 2 nm, as reported in TEM image in Figure 1 A.…”