Design-controlled synthesis of IrO₂ sub-monolayers on Au nanoflowers: marrying plasmonic and electrocatalytic properties

Abstract

Au–IrO2 nanostructures optimized for light harvesting with closely spaced plasmonic branches and catalytic surface area (ultra-thin IrO2 layers) were developed.

Plasmonic catalysis with designer nanoparticles

“…106,107 To this end, we developed nanoflowers based on Au as the plasmonic component and IrO 2 . 108 More specifically, we targeted Au-IrO 2 plasmonic-catalytic nanoparticles displaying a tortuous dendritic morphology, in which several branches around 5 nm in diameter made up of Au are closely spaced to each other as shown in Figure 10A. 108 This enables the plasmon hybridization between the branches, which can lead to high plasmonic catalytic activities because of high electric fields (electromagnetic hot spots, Figure 10B) and the high contribution of absorption relative to scattering to the optical efficiency in this system (Figure 10C).…”

“…108 More specifically, we targeted Au-IrO 2 plasmonic-catalytic nanoparticles displaying a tortuous dendritic morphology, in which several branches around 5 nm in diameter made up of Au are closely spaced to each other as shown in Figure 10A. 108 This enables the plasmon hybridization between the branches, which can lead to high plasmonic catalytic activities because of high electric fields (electromagnetic hot spots, Figure 10B) and the high contribution of absorption relative to scattering to the optical efficiency in this system (Figure 10C). 108 In principle, by covering these branches with an ultrathin (1 nm) and incomplete IrO 2 shell (Figure 10D), the catalytic component can efficiently be exposed to the energy that is harvested from the light because of LSPR excitation, paving the way to improved activities.…”

“…108 This enables the plasmon hybridization between the branches, which can lead to high plasmonic catalytic activities because of high electric fields (electromagnetic hot spots, Figure 10B) and the high contribution of absorption relative to scattering to the optical efficiency in this system (Figure 10C). 108 In principle, by covering these branches with an ultrathin (1 nm) and incomplete IrO 2 shell (Figure 10D), the catalytic component can efficiently be exposed to the energy that is harvested from the light because of LSPR excitation, paving the way to improved activities. Here, the ultrathin and incomplete IrO 2 shell at the surface of each branch maximizes the lightharvesting by Au and the subsequent flow of charge carriers from Au to the Ir-based shell, while also maximizing the IrO 2 surface area and utilization of Ir.…”

Supported Oxygen Evolution Catalysts by Design: Toward Lower Precious Metal Loading and Improved Conductivity in Proton Exchange Membrane Water Electrolyzers

“…46,51 In agreement with previous studies of Au-IrO 2 composites, Au on the contrary, leads to increased Ir oxidation since the binding energies of Au 4f peaks shifting slightly lower. 52 The stability of the Ir surfaces deposited on Pt-CCSs evidenced from XPS spectra in Figure 6 directly correlate to the retention of high OER activities in Figure 3.…”

Completely green synthesis of rose-shaped Au nanostructures and their catalytic applications

“…[11][12][13][14][15][16][17][18] These unique features enable these nanocrystals to be used as advanced and high-performance materials, particularly catalysts. [19][20][21] Several synthesis strategies for synthesizing Au nanostructures with ower-like architectures have been reported, including a so template method, 18 hard template method, 21 electrochemical methods, 15,22 a galvanic replacement reaction, 23 and seeded-growth syntheses. 24,25 Because these approaches require the preparation of complex templates or seeds in advance and tend to involve time-consuming, complicated, or costly processes, the development of a one-pot, easy-toimplement method for preparing Au nanostructures with 3D hierarchical structures is still highly desirable and technically important.…”