Rational Design of Hybrid Nanostructures for Advanced Photocatalysis

Abstract

Nanocatalysis has been a growing field over the past few decades with significant developments in understanding the surface properties of nanocatalysts. With recent advances in synthetic methods, size, shape and composition of the nanoparticles can be controlled in a well defined manner which facilitates achieving selective reaction products in multipath reactions. Nanoparticles with specific exposed crystal facets can have different reactivity than other facets for reaction intermediates, which favours selective pathways during the course of reaction. Heterogeneous catalysts have been studied extensively; nano‐sized metal particles are absorbed on mesoporus supports, facilitating access to the large surface area of the nanoparticles and hence exposure of more catalytic sites. Photocatalysis is attractive area of catalysis, in which photoinduced charge carriers are used for a variety of catalytic applications. More interestingly, clean and renewable liquid fuels energy sources such as hydrogen and methyl alcohol can be generated using photocatalysts through water splitting and CO2 reduction, respectively. Herein, we highlight the progress of nanocatalysis through metal, bimetallic nanoparticle, metal‐semiconductor hybrid nanostructures and oxide nanoparticles for various reactions.

Hierarchical synthesis of non-centrosymmetric hybrid nanostructures and enabled plasmon-driven photocatalysis

“…This type of nc-HN offers an example to examine finely tailored synergistic effects and to reveal new role of plasmons in photocatalysis that has not been settled in the field because of the lack of material control and predictive modelling 9 . Nanoscale photocatalysis represents a promising route for harnessing an electromagnetic process to convert solar to chemical energies 11,[38][39][40] . A typical nanoscale photocatalytic system exclusively involves semiconductor nanostructures, in which photogenerated electron-hole pairs in semiconductors can be rapidly separated at semiconductor-catalyst interfaces to perform redox chemistry at the catalytically active sites 3,9,11,41,42 .…”

“…By combining theoretical modelling with elaborative material control, we elucidate the photocatalytic reaction pathway via a hot plasmon-induced electron transfer mechanism, which can be further confirmed by ultrafast timeresolved optical measurement. Unveiling the electron transfer pathway in a photocatalytic process may lead to a rational design of hybrid materials towards ultimate high quantum efficiencies as well as additional yet-unforeseen applications in other fields [9][10][11][12][13][14] .…”

Metal Domain Size Dependent Electrical Transport in Pt-CdSe Hybrid Nanoparticle Monolayers

“…43,44 A number of studies have demonstrated the excellent photo-catalytic properties of metal-semiconductor HNPs in liquid solution, which are based on an efficient separation of photogenerated charge carriers. 45 The electrons move towards the metallic part of the HNPs from where they can be 3 transferred to reducible species in the solution. Pt-semiconductor combinations belong to the most powerful photocatalysts.…”

Colloidal Magnetic Heterostructured Nanocrystals with Asymmetric Topologies: Seeded-Growth Synthetic Routes and Formation Mechanisms

“…In the realm of nanomaterials, colloidal inorganic nanocrystals (NCs), solution free-standing crystalline nanoparticles entirely synthesized and processable in liquid media, have now raised to the rank of model systems for assessing the foundations of the physical-chemical laws of nanoscale matter owing to the precision and flexibility with which their crystal habit, shape, dimensions, and surface moieties can be tailored in the preparation stage (Burda et al, 2005;Cozzoli et al, 2006;Cozzoli, 2008;Baghbanzadeh et al, 2011). In addition, NCs are robust and versatile enough to be exploited as key active elements in artificial mesoscopic materials, innovative processes, and devices of great fundamental and practical significance for optoelectronics (Talapin et al, 2010;Vanmaekelbergh, 2011), catalysis (Chng et al, 2013;Vaneski et al, 2014;Xu et al, 2016), energy conversion (Carey et al, 2015;Xu et al, 2016) and storage (Frey et al, 2009;Niederberger and Pinna, 2009;Lee and Cho, 2011;Oszajca et al, 2014), sensing (Freeman and Willner, 2012;Palui et al, 2015), environmental remediation (Tong et al, 2012;Wilker et al, 2012;Rawalekar and Mokari, 2013), and biomedicine (Parak et al, 2003;Michalet et al, 2005;Palui et al, 2015).…”

“…In the case of MHNCs embodying magnetic phases and plasmonic metals, abnormally modified or mutually switchable magnetic, optical, and magneto-optical responses may reflect the synergistic interplay of magnetism, magneto-optical activity, and LSPR oscillations through various exchange-coupling mechanisms Jun et al, 2007;Casavola et al, 2008;Carbone and Cozzoli, 2010;Armelles et al, 2013;Pineider et al, 2013;López-Ortega et al, 2015). The possibility of achieving favorable electronic-structure hybridization at the heterointerfaces and of programing chargecarrier destination pathways across interfacial potential barriers of tunable height and widths in HNCs holds great fundamental and practical implications for (photo)catalytic, electrocatalytic, and chemical-sensing applications (Wang et al, 2009c;Costi et al, 2010;Chng et al, 2013;He et al, 2013;Rawalekar and Mokari, 2013;Banin et al, 2014;Song, 2015;Liao et al, 2016). These prerogatives suggest that creation of effective bonding junctions among selected nanoscale domains in appropriately configured MHNCs may be deliberately exploited to engineer their chemical-physical behavior and active functionalities, overcoming intrinsic limitations of single-material NCs (Jun et al, 2007;Casavola et al, 2008;Carbone and Cozzoli, 2010;de Mello Donegà, 2011;Buck and Schaak, 2013;Banin et al, 2014;López-Ortega et al, 2015).…”