Metal–Semiconductor Hybrid Nano-Heterostructures for Photocatalysis Application

Abstract

This chapter will address the development of colloidal synthesis of hybrid metalsemiconductor nanocrystals and their application in the field of photocatalysis. Despite the plethora of examples of different-shaped metal-semiconductor nanostructures that have been reported, metal-tipped semiconductor nanorods are perhaps the most intensively studied, and their use as a photocatalyst will be the focus of the chapter. First, we will discuss different wet-chemical synthesis techniques to control the synthesis of these metal-semiconductor hybrid structures. Afterward, we will discuss their unique physicochemical properties that are a combination of semiconductor and metal properties. Finally, we will showcase several examples from the literature demonstrating the possible application of these unique hybrid structures in photocatalysis.ductors were found to be good photocatalysis, as shown by Costi et al., where redox-based reactions were enhanced by the fact that photogenerated charges in the semiconductor component could be transferred to the metal tip [3]. Such hybrid nanostructures combine different material components into a single nanoparticle and provide a powerful strategy for modifying the properties of nanoparticles. Colloidal metal-tipped semiconductor hybrid nanomaterials were first realized by Banin's group in 2004, where they demonstrated that gold nanocrystals preferentially nucleate and grow at the tips of CdSe nanorods rather than at the sides of the nanorods (Figure 1) [4,5]. These synthetic techniques opened up new possibilities for designing hybrid structures via epitaxial growth between a noble metal and semiconductors in colloidal solution. This can be seen in Figure 2, where TEM images are shown for a few hybrid structures, including Au-CdSe [6,7], Au-ZnSe [8], Au-Bi 2 S 3 [9], Au-SnS [10], and Au-CZTS [11].

Symmetry-Reduced Metal Nanostructures Offer New Opportunities in Plasmonics and Catalysis

“…This example highlights the potential of hybrid NPs composed of metal–semiconductor domains with reduced symmetry. Other hybrid NPs can be synthesized by depositing metal on semiconductor seeds (or vice versa) by leveraging the intrinsic differences in material class and judicious selection of reaction conditions, bringing together materials with different properties synergistically within one nanostructure …”

“…Other hybrid NPs can be synthesized by depositing metal on semiconductor seeds (or vice versa) by leveraging the intrinsic differences in material class and judicious selection of reaction conditions, bringing together materials with different properties synergistically within one nanostructure. 73 Overall, NPs with reduced symmetry display enhanced electro-and photocatalytic properties. Through using heterodimer particles, it is possible to increase the selectivity of electrocatalytic reactions with tandem catalysis.…”

Ag/Cr-TiO2 and Pd/Cr-TiO2 for Organic Dyes Elimination and Treatment of Polluted River Water in Presence of Visible Light

“…The metalized titania has been useful in heterogeneous photocatalysis since this process allows the use of a clean energy source such as sunlight in the elimination of complex pollutants [ 7 , 8 ].…”