Single-molecule photocatalytic dynamics at individual defects in two-dimensional layered materials

Abstract

The insightful comprehension of in situ catalytic dynamics at individual structural defects of two-dimensional (2D) layered material, which is crucial for the design of high-performance catalysts via defect engineering, is still missing. Here, we resolved single-molecule trajectories resulted from photocatalytic activities at individual structural features (i.e., basal plane, edge, wrinkle, and vacancy) in 2D layered indium selenide (InSe) in situ to quantitatively reveal heterogeneous photocatalytic dynamics and surface diffusion behaviors. The highest catalytic activity was found at vacancy in a four-layer InSe, up to ~30× higher than that on the basal plane. Moreover, lower adsorption strength of reactant and slower dissociation/diffusion rates of product were found at more photocatalytic active defects. These distinct dynamic properties are determined by lattice structures/electronic energy levels of defects and layer thickness of supported InSe. Our findings shed light on the fundamental understanding of photocatalysis at defects and guide the rational defect engineering.

Super-resolution imaging of photogenerated charges on CdS/g-C3N4 heterojunctions and its correlation with photoactivity

“…49 A similar phenomenon was also observed for other 2D layered materials using the SRM method. 50 With electrons flowing to CdS in the composite, the holes would preferentially locate at the edge position of g-C 3 N 4 in CS/CN-II. The reason why holes are located at the basal planes of pure g-C 3 N 4 is possibly because electrons are preferable to occupy the high curvature sites at edges without the heterojunction structure.…”

Two-dimensional materials for electrocatalysis and energy storage applications

“…To further meet specific requirements for electrocatalysis and energy storage applications, we correspondingly summarize herein the main characteristics of the intrinsic composition, synthetic and functional modification methods of 2D materials. These approaches include surface functionalization, [11][12][13][14][15][16][17] mechanical or chemical exfoliation, 6,[18][19][20][21][22] forming heterostructures, [23][24][25][26] heteroatoms doping, [27][28][29][30] defects creation 31,32 and valence engineering. 4,22,23 Importantly, the rapidly rising and wide applications in the realms of electrocatalysts and energy storage have recently attracted extensive attention due to everincreasing energy consumption issues; the involved energy storage and conversion devices include supercapacitors, batteries, fuel cells and water-splitting apparatus.…”

Observation of reactions in single molecules/nanoparticles using light microscopy

“…7 Although the resolution of optical microscopy is ineffective for observing objects smaller than the diffraction limit, the optical properties of materials, such as scattering and photoluminescence, enable monitoring of chemical reactions at the single-particle level (Figure 2). 6,[21][22][23][24][25] Therefore, it is necessary to select an appropriate optical microscopic method based on the properties of the target material.…”