1 Introduction
3
et al. 2016a). This offers several perspectives for food applications. For instance,
nanoparticles could be utilized as bioactive compounds in functional foods. Bioactive
compounds found naturally in certain foods have physiological benefits and might
help to reduce the risk of certain diseases such as cancer (Ghorani and Tucker 2015;
Kim et al. 2016). By reducing particle size, nanotechnology contributes to improve
the properties of bioactive compounds such as solubility, prolonged residence time
and delivery properties in the gastrointestinal tract and efficient absorption through
cells (Fabiano et al. 2015). More importantly, functional nanomaterials have opened
up new frontiers in materials science and engineering to be an enabling technology
for creating high-performance energy conversion and storage devices (Gao et al.
2013; Dai et al. 2012).
The energy issue is one of the most significant topics during the twenty-first
century (Pfenninger et al. 2014). It is estimated that the world will need to double its
energy supply by 2050 (Armaroli and Balzani 2007; Cook et al. 2010). An overdependence on the non-renewable fossil fuels poses not only ecological problems but also
serious and continuous impacts on the global society and economy (Asif and Muneer
2007; Omer 2008). Increasing energy demand, reduction of fossil fuel reserves, and
environmental pollution have promoted the research of efficient and low-emission
energy conversion devices (Bromberg et al. 2001). The importance of developing new
types of energy is evident from the fact that global energy consumption is accelerating
at an alarming rate due to the rapid economic growth on the global scale, the increase
of the world population, and the increasing dependence of mankind on energy equipment (Dincer 2000). For this purpose, advanced technologies for both energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries)
have received extensive research around the world. Nanotechnology has opened
up new areas in materials science and engineering to meet this challenge (Arico
et al. 2005). As with all other devices, the performance of energy-related devices
strongly depends on the characteristics of the materials they utilize. Recent development in materials science, particularly nanomaterials, has facilitated the research
and development of energy technologies. Comparing to traditional energy materials,
nanomaterials possess unique properties useful for enhancing the energy conversion
and storage performances (Arico et al. 2005; Zhang et al. 2013). Nanomaterials have
attracted much attention in various energy devices including fuel cells, solar cells,
light-emitting diodes, sensors, lithium-ion batteries, supercapacitors, thermoelectric
devices, and memory devices (Zhao et al. 2015; Wang et al. 2015; Sun et al. 2015a;
Xing et al. 2016; Song et al. 2015; Zhu et al. 2014; Devi et al. 2015; Su et al. 2014;
Wu et al. 2015; Peng et al. 2014; Chen and Dai 2014; Ortega et al. 2017; Tan et al.
2015). As a very promising catalyst for oxygen reduction reactions (ORR), nanomaterials are effective alternatives to Pt-based electrocatalysts in fuel cell systems
(Zhang et al. 2015a; Ganesan et al. 2015). In recent years, nanomaterials have also
been actively researched as electrode materials in lithium-ion batteries and electrochemical supercapacitors (Hu et al. 2015; Mondal et al. 2015; Lu et al. 2017).
The wide application of nanomaterials benefits from the progress in the synthesis of
novel nanostructured materials with different sizes and various topographies. As the
size of nanomaterials is reduced to the nanometer scale, new chemical and physical
3
et al. 2016a). This offers several perspectives for food applications. For instance,
nanoparticles could be utilized as bioactive compounds in functional foods. Bioactive
compounds found naturally in certain foods have physiological benefits and might
help to reduce the risk of certain diseases such as cancer (Ghorani and Tucker 2015;
Kim et al. 2016). By reducing particle size, nanotechnology contributes to improve
the properties of bioactive compounds such as solubility, prolonged residence time
and delivery properties in the gastrointestinal tract and efficient absorption through
cells (Fabiano et al. 2015). More importantly, functional nanomaterials have opened
up new frontiers in materials science and engineering to be an enabling technology
for creating high-performance energy conversion and storage devices (Gao et al.
2013; Dai et al. 2012).
The energy issue is one of the most significant topics during the twenty-first
century (Pfenninger et al. 2014). It is estimated that the world will need to double its
energy supply by 2050 (Armaroli and Balzani 2007; Cook et al. 2010). An overdependence on the non-renewable fossil fuels poses not only ecological problems but also
serious and continuous impacts on the global society and economy (Asif and Muneer
2007; Omer 2008). Increasing energy demand, reduction of fossil fuel reserves, and
environmental pollution have promoted the research of efficient and low-emission
energy conversion devices (Bromberg et al. 2001). The importance of developing new
types of energy is evident from the fact that global energy consumption is accelerating
at an alarming rate due to the rapid economic growth on the global scale, the increase
of the world population, and the increasing dependence of mankind on energy equipment (Dincer 2000). For this purpose, advanced technologies for both energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries)
have received extensive research around the world. Nanotechnology has opened
up new areas in materials science and engineering to meet this challenge (Arico
et al. 2005). As with all other devices, the performance of energy-related devices
strongly depends on the characteristics of the materials they utilize. Recent development in materials science, particularly nanomaterials, has facilitated the research
and development of energy technologies. Comparing to traditional energy materials,
nanomaterials possess unique properties useful for enhancing the energy conversion
and storage performances (Arico et al. 2005; Zhang et al. 2013). Nanomaterials have
attracted much attention in various energy devices including fuel cells, solar cells,
light-emitting diodes, sensors, lithium-ion batteries, supercapacitors, thermoelectric
devices, and memory devices (Zhao et al. 2015; Wang et al. 2015; Sun et al. 2015a;
Xing et al. 2016; Song et al. 2015; Zhu et al. 2014; Devi et al. 2015; Su et al. 2014;
Wu et al. 2015; Peng et al. 2014; Chen and Dai 2014; Ortega et al. 2017; Tan et al.
2015). As a very promising catalyst for oxygen reduction reactions (ORR), nanomaterials are effective alternatives to Pt-based electrocatalysts in fuel cell systems
(Zhang et al. 2015a; Ganesan et al. 2015). In recent years, nanomaterials have also
been actively researched as electrode materials in lithium-ion batteries and electrochemical supercapacitors (Hu et al. 2015; Mondal et al. 2015; Lu et al. 2017).
The wide application of nanomaterials benefits from the progress in the synthesis of
novel nanostructured materials with different sizes and various topographies. As the
size of nanomaterials is reduced to the nanometer scale, new chemical and physical