Catalytic Kinetics of Different Types of Surface Atoms on Shaped Pd Nanocrystals

Abstract

To understand the catalytic properties or roles of different types of surface atoms on metal nanocatalysts,t he catalytic kinetics and dynamics of the different types of surface atoms (plane and edge) were revealed for the first time by astatistical quantitative deconvolution of observables obtained from traditional single-molecule nanocatalysis of Pd nanocrystals.It was found that the edge and plane of Pd nanocubes show similar size-dependent product formation processes,b ut inverse product dissociation processes.T his work helps push the traditional single-molecule nanocatalysis method towards the sub-particle level.Heterogeneous nanocatalysis has attracted considerable attention over the past decades because of its broad applications during chemical manufacturing processes. [1] However,s tudy is often hampered by the difficulty of identifying the properties or roles of different types of surface atoms,s uch as the plane,e dge,o rc orner atoms on as ingle nanoparticle surface. [2][3][4] To elucidate this problem, various experiments and computations have been conducted, [2,[4][5][6][7][8][9][10] but it is still difficult to clarify the quantitative contribution of different types of surface atoms to the total catalytic reactivity of as ingle nanoparticle.I nr ecent years,s inglemolecule fluorescence microscopy (SMFM) has been used to investigate the kinetic and dynamic behaviors of the whole single nanoparticles in real time with single-turnover resolution. [11][12][13][14][15][16][17][18][19] Furthermore,t he activity of different parts of an individual nanocatalyst (from af ew hundred nanometers to microns in size) was visualized approximately using superresolution fluorescence microscopy. [20][21][22] However,o wing to the limitation of spatial resolution and the vague partition of corner,e dge,o rp lane on individual nanocatalysts,t he catalytic kinetic and dynamic study of different types of surface atoms cannot be studied quantitatively with SMFM.In this work, based on well-defined palladium (Pd) nanocubes and rational physical models,b yastatistical quantitative deconvolution of observables obtained from traditional single-molecule nanocatalysis of Pd nanocrystals, the catalytic kinetics and dynamics of the different types of surface atoms (plane and edge) were studied quantitatively for the first time.T his work pushes traditional SMFM as tep forward to sub-particle level. [18] Here,t he face-centered cubic (fcc) Pd nanocubes with uniform sizes were synthesized according to previous methods (Supporting Information). [23][24] Figures 1a-c and S1 a, bshow typical transmission electron microscope (TEM) images of five sets of Pd nanocubes in different sizes.T he fcc Pd nanocube is mainly enclosed by {100} facets,w hich was confirmed by Figure S1c-e. [25] Thec orresponding size and shape distributions are shown in Figures S2 and S3, where the five sets of Pd nanocubes were, onaverage,5.2, 7.0, 11.4, 15.2, and 22.2 nm in edge length, respectively.S ingle-molecule nanocatalysis was performed based o...

Influence of Reduction Kinetics on the Preparation of Well-Defined Cubic Palladium Nanocrystals

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In situ quantitative single-molecule study of site-specific photocatalytic activity and dynamics on ultrathin g-C3N4 nanosheets

“…This is probably due to the steric effect on the basal plane, in which the large planar π–π resazurin molecule preferably lays down on the flat basal plane via the van der Waals (vdW) force. 43,44 Therefore, the basal plane exhibits the largest K RZ with the strongest vdW force with resazurin. However, wrinkles with a folding or bending configuration and the sharp edges would obstruct the flat adsorption of aromatic resazurin and weaken the vdW force, which reduces the K RZ of these structures.…”

Monodisperse Pd Nanotetrahedrons on Ultrathin MoO3–x Nanosheets as Excellent Heterogeneous Catalyst for Chemoselective Hydrogenation Reactions

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