Comparison of atomic scale dynamics for the middle and late transition metal nanocatalysts

Abstract

Catalysis of chemical reactions by nanosized clusters of transition metals holds the key to the provision of sustainable energy and materials. However, the atomistic behaviour of nanocatalysts still remains largely unknown due to uncertainties associated with the highly labile metal nanoclusters changing their structure during the reaction. In this study, we reveal and explore reactions of nm-sized clusters of 14 technologically important metals in carbon nano test tubes using time-series imaging by atomically-resolved transmission electron microscopy (TEM), employing the electron beam simultaneously as an imaging tool and stimulus of the reactions. Defect formation in nanotubes and growth of new structures promoted by metal nanoclusters enable the ranking of the different metals both in order of their bonding with carbon and their catalytic activity, showing significant variation across the Periodic Table of Elements. Metal nanoclusters exhibit complex dynamics shedding light on atomistic workings of nanocatalysts, with key features mirroring heterogeneous catalysis.

Imaging an unsupported metal–metal bond in dirhenium molecules at the atomic scale

“…S1). If several precursor molecules Re 2 (CO) 10 are agglomerated in the nanotube, they form a metal nanocluster with several Re atoms under these conditions (16,17); in the case of a single isolated molecule, Re 2 (CO) 10 ligand elimination yields a well-defined Re 2 molecule as observed by aberration-corrected high-resolution TEM (AC-HRTEM) (three typical images of Re 2 are shown in Fig. 1A).…”

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

“…These results give rise to an inspiration that the gap between the heterogeneous catalytic processes of nanocatalysts and SACs would be bridged by the co-catalysis. Significantly, this inspiration is indirectly supported by experimental observations that metal nanoclusters or substrates can release metal SAs and they co-catalyze the growth of carbon nanostructures in all-solid-phase catalysis [29][30][31] . However, up to now, no experimental evidence has been reported for the emergence of SACs in any heterogeneous catalysis process of nanocatalysts.…”

“…However, up to now, no experimental evidence has been reported for the emergence of SACs in any heterogeneous catalysis process of nanocatalysts. Meanwhile, even though the dynamic processes of metal SAs to catalyze the growth of carbon nanostructures in all-solid-phase catalysis have been impressively demonstrated 27,[29][30][31] , no published works in the literature give direct observations on any heterogeneous catalysis process of SACs. Thus, it remains elusive whether the co-catalysis exists in any heterogeneous catalysis process initiated by either of nanocatalysts and SACs.…”

Effect of Temperature on the Nucleation and Growth of Precious Metal Nanocrystals

“…Recent progresses in microscopy have allowed for the development of the chemTEM approach . This approach uses both capabilities of modern high‐resolution transmission electron microscopy (TEM; sub‐Ångstrom imaging probe and electron beam as a tuneable source of energy) to induce chemical transformations at the atomic level, with concomitant imaging of such transformations in real time and in real space …”