Imaging the electrocatalytic activity of single nanoparticles

Abstract

The electrocatalytic properties of nanoparticles depend on their size, shape and composition. These properties are typically probed by measuring the total electrocatalytic reaction current of a large number of nanoparticles, but this approach is time-consuming and can only measure the average catalytic activity of the nanoparticles under study. However, the identification of new catalysts requires the ability to rapidly measure the properties of nanoparticles synthesized under various conditions and, ideally, to measure the electrocatalytic activity of individual nanoparticles. Here, we show that a plasmonic-based electrochemical current-imaging technique can simultaneously image and quantify the electrocatalytic reactions of an array of 1.6 × 10(5) platinum nanoparticles printed on an electrode surface, which could facilitate high-throughput screening of the catalytic activities of nanoparticles. We also show that the approach can be used to image the electrocatalytic reaction current and measure the cyclic voltammograms of single nanoparticles.

Plasmonic imaging of protein interactions with single bacterial cells

“…1a) described in detail elsewhere. Shan et al, 2012;Wang et al, , 2011 Briefly, the setup is based on an inverted optical microscope The individual bacteria were imaged as distinct V--shaped patterns (Fig. 1c), which match well with the positions of the bacteria in the Bright--field optical image (Fig.…”

Intermittent photocatalytic activity of single CdS nanoparticles

“…SPRM is an optical microscopy that we recently developed to image the local refractive index (RI) distribution with a temporal resolution up to microseconds and a spatial resolution around the diffraction limit (19)(20)(21). SPRM is capable of monitoring local H 2 concentration due to the large difference in the RI between H 2 O and H 2 .…”

“…) was used to excite planar surface plasmons on the gold film with an objective-based total internal reflection configuration (19)(20)(21). Light reflected from the gold film was collected via the same objective and directed into a camera to form an SPRM image.…”

“…1A, which reveals each nanoparticle as a bright spot with a long parabolic tail. This parabolic tail is due to scattering of the surface plasmonic waves by the nanoparticle that has a diameter smaller than the diffraction limit (21,25). The CdS nanoparticle-covered gold film was illuminated from the top with a blue light (λ < 500 nm, 14 mW·mm (A) Schematic illustration of SPRM setup for monitoring the H 2 production rate on single CdS NPs.…”

By any other name

“…In physics, we've published many science papers, from the purely analytical 1 to numerical calculations 2 to the primarily experimental 3 . Similarly, in chemistry, we've published basic work in electrocatalysis, like that shown on the cover of this issue 4 , and DNA methylation 5 , as well as the synthesis of complex nanostructures ( Fig. 1) …”