In Situ Imaging Facet-Induced Spatial Heterogeneity of Electrocatalytic Reaction Activity at the Subparticle Level via Electrochemiluminescence Microscopy

Abstract

Investigating catalytic behavior of heterogeneous catalysts, especially at the crystal facets level, is crucial for rational catalyst design in the energy and environmental fields. Here we demonstrate an efficient approach to in situ visualize and analyze the heterogeneity of electrocatalytic activity on different facets at the subparticle level via electrochemiluminescence (ECL) microscopy. ZnO crystals with various exposed facet proportions were synthesized, and the correlation between their electrocatalytic performance toward luminol analogue degradation and the exposed facets is established. It is clearly imaged that the ZnO (002) facet has superior catalytic performance compared to the ZnO (100) facet, which is supported by theoretical computation and electrochemical experiments as the facet-induced heterogeneity of the catalytic effect on oxygen reduction into the key reactant for ECL. Accordingly, the spatial heterogeneity of electrocatalytic activity at different facets on one particle is visualized for the first time. The realization of subparticle ECL imaging and kinetic analysis could provide a special approach to visualize facet-induced spatial heterogeneity of catalytic behavior and valuable information for the catalysis study and analysis.

High-resolution imaging of catalytic activity of a single graphene sheet using electrochemiluminescence microscopy

“…L012 and O 2 ) at the surface. 27 The computational result confirms that the ECL reaction will easily start once the ECL reactants are absorbed onto the surface of the catalyst. Since rGO can electrocatalyze the reaction between L012 and H 2 O 2 to emit ECL light, 36 it is reasonable to assume that L012 and hydrogen peroxide are adsorbed at the surface of rGO.…”

“…In our previous studies, we observed that active sites in a single particle induce the generation of hydroperoxide intermediates, which behave as coreactants to remarkably enhance ECL emission from luminol. 27,28 As a result, the ECL intensity of the particles is visualized, which has been proven to be correlated with their catalytic activity. Nevertheless, time resolution must be sacrificed to obtain sufficient ECL emission from single particles due to the relatively weak ECL emission.…”

“…It has the advantages of simple setup and near-zero background signal so that it has been successfully applied to image immunosensors [16][17][18][19][20] and single particle's behavior [21][22][23][24][25][26] with a spatiotemporal resolution. In our previous studies, active sites in a single particle induce the generation of hydroperoxide intermediates, which behave as correactants to remarkably enhance ECL emission from luminol 27,28 . As a result, the ECL intensity of the particles is visualized, which has been proven to be correlated with their catalytic activity.…”

Electrogenerated chemiluminescence detection of single entities

“…1b). 38,39,53 A microscope objective with a high numerical aperture (N.A.) is preferred to increase the collection efficiency.…”

Recent progress in gas nanobubble electrochemistry

“…(fluorescence microscopy) [76] 、暗场显微镜(dark field microscopy) [77~79] 、表面等离激元共振显微镜(surface plasmon resonance microscopy) [80,81] 、电致化学发光显 微镜(electrochemiluminescence microscopy) [82] 等一些 先进光学成像手段被广泛用于单个纳米粒子微观化学 过程研究, 特别是电化学过程(例如Pt纳米粒子电催化 析氢 [80] 、Ag纳米粒子电化学氧化溶解 [83] 、Au或Ag纳 米粒子的电沉积 [77,79] [72] (网络版彩图) Figure 4 Scheme for tip generation-substrate collection mode SECM for the removal of gas nanobubbles [72] (color online).…”