390
A. Donia et al.
coupled with the existence of lead-resistant MKH1 bacteria, the required Ag nanoparticles were synthesized. Electrochemical hydrazine oxidation led to the development
of association between current density peak and the Ag catalyst content. The authors
revealed that as a result of the accumulation of Ag nanoparticles, no increase was
observed in the current density even when Ag nanoparticle content surpassed the
threshold value as showed by the forward scan. Ag nanoparticles displayed highlevel stability as well as a significant catalytic efficiency. The impedance results and
chronoamperometry tests of the biosynthesized Ag nanoparticles were an indicator
of their capability in hydrazine fuel cells (Rostami et al. 2018).
5 Sensing Applications
Sensing pollutants are pivotal to protect the environment from their disastrous effects.
Many protection agencies have determined and set the maximum tolerable levels of
known pollutants in the world. Determining the concentration and type of the pollutant requires chemical, biological, and physical assays. Sampling and the subsequent
laboratory analysis of the samples are time-consuming, expensive, and laborious,
resulting to be the main limitations of these assays. It is challenging to ascertain the
precise nature and composition of the pollutant under field circumstances with the
traditional methods. A sensor could help in monitoring the infield environment but at
the cost of specificity and detection limit. Ongoing research mainly focuses on ways
to increase the specificity, selectivity, and sensitivity of the sensors for monitoring
of the environment. This can be achieved in two possible ways: The first one is to
target the binding between the recognition element and the contaminant, whereas
the second one is to improve the electronic interface and transduction to the sensing
layer (Mehndiratta et al. 2013).
Developing the detection methods will provide fast and accurate detection of
pollutants. The sensors should be remote and portable to facilitate pollutant detection
over large field areas. A sensor is a tool that can detect compounds (chemical or
biological) by generating a digital electronic signal via interaction with the compound
it has been designed to detect. Conventional sensors can identify the pollutants in
biological samples, air, water, soil, and chemical compounds. They are also capable
of detecting industrial products at low levels up to ppm and ppb (Kumar et al. 2017).
Using nanoparticles, these detection levels could be increased. Nanoparticle
sensors can be designed to have high specificity and accuracy. Even at significantly
low concentrations, nanoparticle sensors can uncover microbial pathogens, heavy
metals, and organic compounds (Formoso et al. 2016). The reactivity increases with
the increase in surface area to volume ratio, which also enhances sensitivity. Multiplex sensors have the ability to detect multiple compounds, based on the idea that
the small size improves the quantity of reactive sites on the sensor. The development
of nanosensors in the shape of nanotubes and nanowires helps in monitoring of the
environment. Detection of NH 3 and NO 2 using single-walled carbon nanotubes has
A. Donia et al.
coupled with the existence of lead-resistant MKH1 bacteria, the required Ag nanoparticles were synthesized. Electrochemical hydrazine oxidation led to the development
of association between current density peak and the Ag catalyst content. The authors
revealed that as a result of the accumulation of Ag nanoparticles, no increase was
observed in the current density even when Ag nanoparticle content surpassed the
threshold value as showed by the forward scan. Ag nanoparticles displayed highlevel stability as well as a significant catalytic efficiency. The impedance results and
chronoamperometry tests of the biosynthesized Ag nanoparticles were an indicator
of their capability in hydrazine fuel cells (Rostami et al. 2018).
5 Sensing Applications
Sensing pollutants are pivotal to protect the environment from their disastrous effects.
Many protection agencies have determined and set the maximum tolerable levels of
known pollutants in the world. Determining the concentration and type of the pollutant requires chemical, biological, and physical assays. Sampling and the subsequent
laboratory analysis of the samples are time-consuming, expensive, and laborious,
resulting to be the main limitations of these assays. It is challenging to ascertain the
precise nature and composition of the pollutant under field circumstances with the
traditional methods. A sensor could help in monitoring the infield environment but at
the cost of specificity and detection limit. Ongoing research mainly focuses on ways
to increase the specificity, selectivity, and sensitivity of the sensors for monitoring
of the environment. This can be achieved in two possible ways: The first one is to
target the binding between the recognition element and the contaminant, whereas
the second one is to improve the electronic interface and transduction to the sensing
layer (Mehndiratta et al. 2013).
Developing the detection methods will provide fast and accurate detection of
pollutants. The sensors should be remote and portable to facilitate pollutant detection
over large field areas. A sensor is a tool that can detect compounds (chemical or
biological) by generating a digital electronic signal via interaction with the compound
it has been designed to detect. Conventional sensors can identify the pollutants in
biological samples, air, water, soil, and chemical compounds. They are also capable
of detecting industrial products at low levels up to ppm and ppb (Kumar et al. 2017).
Using nanoparticles, these detection levels could be increased. Nanoparticle
sensors can be designed to have high specificity and accuracy. Even at significantly
low concentrations, nanoparticle sensors can uncover microbial pathogens, heavy
metals, and organic compounds (Formoso et al. 2016). The reactivity increases with
the increase in surface area to volume ratio, which also enhances sensitivity. Multiplex sensors have the ability to detect multiple compounds, based on the idea that
the small size improves the quantity of reactive sites on the sensor. The development
of nanosensors in the shape of nanotubes and nanowires helps in monitoring of the
environment. Detection of NH 3 and NO 2 using single-walled carbon nanotubes has