Self-activated surface dynamics in gold catalysts under reaction environments

Abstract

Nanoporous gold (NPG) with sponge-like structures has been studied by atomic-scale and microsecond-resolution environmental transmission electron microscopy (ETEM) combined with ab initio energy calculations. Peculiar surface dynamics were found in the reaction environment for the oxidation of CO at room temperature, involving residual silver in the NPG leaves as well as gold and oxygen atoms, especially on {110} facets. The NPG is thus classified as a novel self-activating catalyst. The essential structure unit for catalytic activity was identified as Au–AgO surface clusters, implying that the NPG is regarded as a nano-structured silver oxide catalyst supported on the matrix of NPG, or an inverse catalyst of a supported gold nanoparticulate (AuNP) catalyst. Hence, the catalytically active structure in the gold catalysts (supported AuNP and NPG catalysts) can now be experimentally unified in low-temperature CO oxidation, a step forward towards elucidating the fascinating catalysis mechanism of gold.

Dynamic co-catalysis of Au single atoms and nanoporous Au for methane pyrolysis

“…Finally, the films floated on the surface of ultrapure water, and they were NPG pieces. This synthesis is the same as reported [34][35][36][37][38] . For conventional and in situ TEM characterizations, conventional TEM grids and sample chips from the DENS solutions company at The Netherlands were used, respectively, to collect NPG pieces from the water surface.…”

“…The NPG samples were prepared by dealloying, and they possess bicontinuous pore channels and ligaments [32][33][34][35][36][37][38] . For instance, the as-prepared sample in Fig.…”

“…Meanwhile, Au nanocatalysts and their derived catalysts have exhibited excellent catalytic activities for CH 4 activation and use 9,10,14 . As a new type of Au nanocatalyst with threedimensional (3D) bicontinuous porous structure [32][33][34][35][36][37][38] , nanoporous gold (NPG) has shown high performances in heterogeneous catalysis 32,36,37 . Its unique structure has large specific surface area, low density, and high permeability, which are all advantageous for heterogeneously catalytic reactions [32][33][34][35][36][37][38] .…”

Differences in the Catalytic Behavior of Au-Metalized TiO2 Systems During Phenol Photo-Degradation and CO Oxidation

“…In addition, it has been demonstrated that these may enhance also the interaction between gold and the surface of the oxide [2]. Consequently, the reduction of the catalyst could counteract the sintering produced by the increase in temperature, taking also into account the possible dynamic re-dispersion of deposited gold nanoparticles in different supports depending on the atmosphere reported in literature [2,40,41]. However, this has to be confirmed and deeply analyzed through further experiments revealing more insights about the effects of the activation process in the studied catalysts.…”

Visualizing Progressive Atomic Change in the Metal Surface Structure Made by Ultrafast Electronic Interactions in an Ambient Environment

“…Electronically induced atomic and molecular dynamics must be elucidated in real time, real space, and real environments toward further advancing any scientific, engineering, and industrial fields. It has recently been reported that the atomic dynamics can be captured on the surface of a solid catalyst as a result of electronic reactions in a reaction environment . The catalytic reaction is considered to be triggered by the random collision of reactive gas molecules with the catalyst surface.…”