Symmetry Breaking in Monometallic Nanocrystals toward Broadband and Direct Electron Transfer Enhanced Plasmonic Photocatalysis

Abstract

Metallic nanocrystals manifest themselves as fascinating light absorbers for applications in plasmon-enhanced photocatalysis and solar energy harvesting. The essential challenges lie in harvesting the full-spectrum solar light and harnessing the plasmon-induced hot carriers at the metal-acceptor interface. To this end, a cooperative overpotential and underpotential deposition strategy is proposed to mitigate both the challenges. Specifically, by utilizing both ionic additive and thiol passivator to introduce symmetry-breaking growth over gold icosahedral nanocrystals, the microscopic origin can be attributed to the site-specific nucleation of stacking faults and dislocations. By adopting asymmetric crystal shape and unique surface facets, such nanocrystals attain high activity toward photocatalytic ammonia borane hydrolysis, arising from combined broadband plasmonic properties and enhanced direct transfer of hot electrons across the metal-adsorbate interface.

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

“…Efficient light harvesting can be achieved through broadband optical absorption, such as a broad absorption in LSPR. An example of such is through the symmetry reduction of Au icosahedral seeds through a cooperative overpotential and underpotential deposition strategy . The reduction in symmetry from seed ( I h symmetry) to the resulting particle (quasi- C 5 v , Figure A) led to a broadening of the plasmon band (Figure B), in which the resulting NPs had a significantly broadened LSPR compared to their more symmetric counterparts .…”

“…These broadband optical features make symmetry-reduced NPs attractive for photochemical reactions. Specifically, the symmetry-reduced NPs outperformed their more symmetric counterparts in terms of turnover frequency (Figure C) for the hot electron-driven photocatalysis of ammonia borane hydrolysis . Specifically, the hydrolysis of ammonia borane was studied in which a xenon lamp illuminated the NPs in the presence of ammonia borane in which the symmetry-reduced NPs outperformed the more symmetric counterparts (Figure C) in terms of turnover frequency.…”

“…(F) Amperometric J – t curves of Au–Cu 2 O NPs with octahedral Cu 2 O domains (red), Au–Cu 2 O NPs with cubic Cu 2 O domains with 30 nm exposed Au surface (blue), 38 nm exposed Au surface (magenta), 11 nm exposed Au surface (green), Au@Cu 2 O NPs (purple), and pure Cu 2 O cubes (black). Parts A–C are adapted with permission from ref . Copyright 2020 Wiley-VCH Publishing.…”

“…An example of such is through the symmetry reduction of Au icosahedral seeds through a cooperative overpotential and underpotential deposition strategy. 70 The reduction in symmetry from seed (I h symmetry) to the resulting particle (quasi-C 5v , Figure 5A) led to a broadening of the plasmon band (Figure 5B), in which the resulting NPs had a significantly broadened LSPR compared to their more symmetric counterparts. 70 These broadband optical features make symmetry-reduced NPs attractive for photochemical reactions.…”

Instantaneous Property Prediction and Inverse Design of Plasmonic Nanostructures Using Machine Learning: Current Applications and Future Directions

“…The optical and electronic properties of plasmonic nanoparticles are determined by their composition, morphologies, the dielectric environment surrounding the nanoparticles, and the nature of the metal-dielectric interface (Figure 1e) [36][37][38][39][40][41][42]. Catalytic properties are determined by the exposed crystal facets as well as the adsorption energy of reactant molecules on the nanoparticle surface [43][44][45]. The availability of a library of structure-property relationships for different values of geometric, structural, compositional and environmental factors is much needed for the rational design of plasmonic devices.…”