Strain evolution in nanoporous gold during catalytic CH4 pyrolysis by in situ gas-phase transmission electron microscopy.

Nanoporous gold (NPG) is a novel unsupported heterogeneous catalyst intrinsically loaded under stress and strain. Most studies on the correlation between strain and NPG catalytic activity are limited to ex situ chemical analysis and numerical simulations; few studies have investigated the strain evolution in NPG during catalytic reactions. Herein, in situ gas-phase transmission electron microscopy with high spatiotemporal resolution imaging was conducted to study the evolution of strain in the ligaments of the NPG during catalytic methane pyrolysis. The adsorption and desorption of reactant gases and intermediates altered the ligament structure. The release of stress promoted the formation of dislocations and twins; subsequently, the dislocations glided and interacted with twin boundaries. This study elucidates the evolution of strain in catalytic reactions and can facilitate the development of new approaches to tune the catalytic reactivity of heterogeneous catalysts via strain engineering. [Display omitted] [ABSTRACT FROM AUTHOR]