Reversible gas–solid reaction in an electronically-stimulated palladium nanogap

Abstract

A reversible gas–solid reaction occurs on the tip surface of a positively biased palladium electrode in nitrogen in ETEM apparatus.

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

“…The catalytic reaction is considered to be triggered by the random collision of reactive gas molecules with the catalyst surface. Here we visualize the progressive change in the atomic structure of a metal surface in an ambient environment by applying in situ transmission electron microscopy (TEM) under a strong electrostatic field . The elemental excitation behind the observed phenomena is extremely fast electron tunneling that activates oxygen gas molecules for 10 −15 s (fs) to 10 −18 s (as) .…”

“…[10][11][12][13] The catalytic reaction is considered to be triggered by the random collision of reactive gas molecules with the catalyst surface.H ere we visualize the progressive change in the atomic structure of am etal surface in an ambient environment by applying in situ transmission electron microscopy (TEM) under as trong electrostatic field. [14,15] Thee lemental excitation behind the observed phenomena is extremely fast electron tunneling [16] that activates oxygen gas molecules for 10 À15 s( fs) to 10 À18 s( as). [2] Thed irect visualization, made possible for the first time in this study,p rovides us with ac rucial starting point to understand the electronic and thermic effects to progressively change the atomic structure by catalytic chemical, surface chemical, electrochemical, and biochemical reactions in the nanometer dimension and in an ambient environment.…”

Atomic-scale ETEM Observation of Chemical Reactions on the Surface of Nanomaterials

“…We have investigated atomic structures and dynamics of nanomaterials under reaction conditions by ETEM while taking into account the effects of electron irradiation [2][3][4][5][6][7]. We have found that the surface of Pt nanoparticles is oxidized in O2 gas under electron irradiation ( Figure 1).…”

“…Figure 2. A PdN nanostructure formed on the surface of the positive Pd electrode in an electrically-biased nanogap with N2 gas [6]. The biasing voltage between the electrodes,is (a) 0 V and (b) 8.0 V.…”

“…In addition, we have found an unexpected gas-solid reaction that occurs in an electrically-biased Pd nanogap with N2 gas under electron irradiation ( Figure 2). A PdN compound was synthesized on the surface of the positive Pd electrode at room temperature [6]. It is most likely that the above mentioned oxidation of Pt and Co nanoparticles and the formation of PdN compounds were induced by electronic excitations of metal atoms and gas molecules, involving high-energy electrons and associated secondary electrons that are emitted from the samples by the irradiation of high-energy electrons.…”