Nanocomposite of polypyrrol and silica rods-gold nanoparticles core–shell as an ammonia sensor

Abstract

Ammonia is widely needed in the chemical industry as well as in fertilizers for agriculture. However, in small as well as large quantities, it is not only hazardous for human health but also for our ecosystem. Therefore, ammonia sensing at low concentration with high sensitivity, selectivity and low response time as well as recovery time is important. Here, various nanosensors are fabricated using gold nanoparticles (∼15 nm), silica-gold nanoparticles coreshell particles and coreshell particles embedded in polypyrrol. Comparisons with bare polypyrrol and coreshell particles are also made. In fact, two types of coreshell particles with rod (∼300 nm×2 μm) shape and spheres (200 nm) of silica were used to anchor gold nanoparticles on them. A comparison showed that silica-gold core-shell particle with silica rods had the highest sensitivity (∼166% @ 130 ppm) amongst all. The sensor is simple to operate (only resistance change is measured), requires no heater as the sensing occurs at room temperature, and showed no response, except for ammonia, to other gases or humidity. It also has a low response time (4 s) and recovery time (10 s) at the lowest (10 ppm) ammonia concentration measured here. Thus, a simple, economical ammonia sensor has been demonstrated here.

Ruthenium-decorated vanadium pentoxide for room temperature ammonia sensing

“…Use of log-log scale has been made earlier for plotting the sensitivity. 44,45 We have also determined the response time and recovery times for each concentration from Fig. 9(a).…”

Properties of conductive polymer hydrogels and their application in sensors

“…With the rapid development of society, a large number of poisonous gases produced by industry and agriculture, including carbon oxides (COx), nitrogen oxides (NOx), sulfur dioxide (SO 2 ), and ammonia (NH 3 ), seriously endangering the environment and human health . In addition, some gases are considered as biomarker of human diseases (e.g., monitoring NOx can be used for invasive detection of lung infections and bowel disease) . Therefore, sensitive gas sensing has been attached great importance for hazardous monitoring, human healthcare, and food spoilage detection .…”

“…[111][112][113][114][115] In addition, some gases are considered as biomarker of human diseases (e.g., monitoring NOx can be used for invasive detection of lung infections and bowel disease). [116][117][118][119] Therefore, sensitive gas sensing has been attached great importance for hazardous monitoring, human healthcare, and food spoilage detection. 120,121 However, commercially available gas sensors are mainly metal oxide-based sensors with drawbacks like high working temperature and low sensitivity.…”