Designing Novel Photocatalysts for Disinfection of Multidrug-Resistant …
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NCs. These two-component organization of NCs, have attracted tremendous interests in contrast to the conventional one-component systems. Core-Shell NCs possess
improvised characteristics due to their multifunctional magnetic, chemical and optical properties, higher stability in harsh environmental conditions and high surface
area (Das et al. 2015; Tripathy et al. 2013). Owing to the above factors, core–shell
NCs have found more recognition in the field of chemical sensors, electro-optics,
enhanced drug delivery, immobilization of enzyme, catalysis, and photocatalysis.
It has been discussed earlier that lower quantum efficiency of photocatalytic systems resulting from the faster electron–hole recombination in semiconductor and
the unproductive use of visible light for semiconductors of wider bandgap are the
two critical challenges obstructing the usage of photocatalysis for real-time applications (Chong et al. 2010). Thus, tuning the physical and chemical properties of the
photocatalyst is of greater interest for the real-world applications for creation of sustainable environment and meeting the increasing demands of energy. Photocatalyst
doping has been a technique of choice for this purpose. Moreover, optimization of the
shape, structure, topology and minor defects of the photocatalysts has significantly
influenced their prospective for photocatalytic applications. Semiconductor-based
core–shell NCs, which involve integration of improved composition and structural
features, have been promising for photocatalytic applications (Liu et al. 2012). CoreShell NCs generally avoid the usage of strong chemical oxidants and have been considered ‘green’ as far as the process of synthesis is concerned. Their variants include
metal–semiconductor (Au@ZnO, Ag@ZnO, Ag@TiO 2 ) semiconductor–semiconductor (CdS-TiO 2 , TiO 2 @ZnO), semiconductor–shell (graphene and SiO 2 ) (Liu et al.
2012).
Metal-cored–semiconductor shell NCs are the mostly studied photocatalysts in
the field of transformation of organic refractory organics into less toxic by-products
and intermediates due to their robust structural properties. The metallic core in the
core-shell NCs possessing low Fermi energy level can serve as an electron pool during photoactivation, prolonging the existence of charge carriers, and thus possibly
increasing the overall photocatalytic efficiency of the NCs Fig. 5 (Das et al. 2015).
Moreover, their useful construction can not only increase the stability of core metallic
NP from aggregation but also defend them against undesirable corrosion or leaching
during practical application. Their flawless three-dimensional architecture also facilitates the proper interfacial charge transfer between metallic core and semiconductor
shell. These exceptional merits profoundly linked with the metal-core–semiconductor shell NCs promise their immense prospective as a novel alternative to novel lightharvesting photocatalysts for real-life heterogenous photocatalytic applications (Liu
et al. 2012).
Semiconductor–Semiconductor Core–Shell photocatalysts is a successful
approach for improvising the photocatalytic performance of a semiconductor system. This technology involves coupling two semiconductor particles with diverse
energy or bandgap levels to accomplish effectual charge separation and subsequent
generation of ROS (Chong et al. 2010). In such coupled systems, on photoactivation,
the photo-generated electrons gather at the lower lying CB of one semiconductor
while subsequently accumulating the h
+ at the VB of the other semiconductor. Liu
455
NCs. These two-component organization of NCs, have attracted tremendous interests in contrast to the conventional one-component systems. Core-Shell NCs possess
improvised characteristics due to their multifunctional magnetic, chemical and optical properties, higher stability in harsh environmental conditions and high surface
area (Das et al. 2015; Tripathy et al. 2013). Owing to the above factors, core–shell
NCs have found more recognition in the field of chemical sensors, electro-optics,
enhanced drug delivery, immobilization of enzyme, catalysis, and photocatalysis.
It has been discussed earlier that lower quantum efficiency of photocatalytic systems resulting from the faster electron–hole recombination in semiconductor and
the unproductive use of visible light for semiconductors of wider bandgap are the
two critical challenges obstructing the usage of photocatalysis for real-time applications (Chong et al. 2010). Thus, tuning the physical and chemical properties of the
photocatalyst is of greater interest for the real-world applications for creation of sustainable environment and meeting the increasing demands of energy. Photocatalyst
doping has been a technique of choice for this purpose. Moreover, optimization of the
shape, structure, topology and minor defects of the photocatalysts has significantly
influenced their prospective for photocatalytic applications. Semiconductor-based
core–shell NCs, which involve integration of improved composition and structural
features, have been promising for photocatalytic applications (Liu et al. 2012). CoreShell NCs generally avoid the usage of strong chemical oxidants and have been considered ‘green’ as far as the process of synthesis is concerned. Their variants include
metal–semiconductor (Au@ZnO, Ag@ZnO, Ag@TiO 2 ) semiconductor–semiconductor (CdS-TiO 2 , TiO 2 @ZnO), semiconductor–shell (graphene and SiO 2 ) (Liu et al.
2012).
Metal-cored–semiconductor shell NCs are the mostly studied photocatalysts in
the field of transformation of organic refractory organics into less toxic by-products
and intermediates due to their robust structural properties. The metallic core in the
core-shell NCs possessing low Fermi energy level can serve as an electron pool during photoactivation, prolonging the existence of charge carriers, and thus possibly
increasing the overall photocatalytic efficiency of the NCs Fig. 5 (Das et al. 2015).
Moreover, their useful construction can not only increase the stability of core metallic
NP from aggregation but also defend them against undesirable corrosion or leaching
during practical application. Their flawless three-dimensional architecture also facilitates the proper interfacial charge transfer between metallic core and semiconductor
shell. These exceptional merits profoundly linked with the metal-core–semiconductor shell NCs promise their immense prospective as a novel alternative to novel lightharvesting photocatalysts for real-life heterogenous photocatalytic applications (Liu
et al. 2012).
Semiconductor–Semiconductor Core–Shell photocatalysts is a successful
approach for improvising the photocatalytic performance of a semiconductor system. This technology involves coupling two semiconductor particles with diverse
energy or bandgap levels to accomplish effectual charge separation and subsequent
generation of ROS (Chong et al. 2010). In such coupled systems, on photoactivation,
the photo-generated electrons gather at the lower lying CB of one semiconductor
while subsequently accumulating the h
+ at the VB of the other semiconductor. Liu