S C

IE N

T IF

IC H

IG H

LI G

H T

S M

A T

E R

IA L

S F

O R

T O

M O

R R

O W

'S I

N N

O V

A T

IV E

A N

D S

U S

T A

IN A

B L

E I

N D

U S

T R

Y

6 7 I H I G H L I G H T S 2 0 2 3

PRINCIPAL PUBLICATION AND AUTHORS

Graphene at Liquid Copper Catalysts: Atomic-Scale Agreement of Experimental and First-Principles Adsorption Height, H. Gao (a), V. Belova (b), F. La Porta (b), J. Santiago Cingolani (c), M. Andersen (d), M. Saedi (e), O.V. Konovalov (b), M. Jankowski (b), H.H. Heenen (a), I.M.N. Groot (e), G. Renaud (f), K. Reuter (a), Adv. Sci. 9, 2204684 (2022); https:/doi.org/10.1002/advs.202204684 (a) Fritz-Haber-Institut der Max-Planck-Gesellschaft (Germany) (b) ESRF (c) Technische Universität München (Germany) (d) Aarhus University (Denmark) (e) Leiden University (The Netherlands) (f) Université Grenoble Alpes (France)

determined the adsorption height of monolayer graphene above liquid Cu, known as the gap , experimentally and computationally (Figure 48b). It was found that the experimental value of the gap was 2.2 Å, whereas the computational or theoretical value was 2.119 Å. With a less than 0.1 Å difference, the results demonstrated an almost quantitative agreement between theory and experiment.

The results show that ML potentials trained with first principles are a powerful approach that can determine the gap with sub-angstrom potential while being in good agreement with the experimental value. This is a prerequisite for future detailed mechanistic investigations. Surprisingly, the computational techniques reveal that the interaction of graphene with solid and liquid Cu is chemically identical, thus adding to the mystery of the superior synthesis from the liquid metal state. These powerful insights can serve to advance the understanding of seamless graphene synthesis to develop next- generation electronics.

Fig. 48: a) Experimental X-ray reflectivity curves taken in situ from the bare liquid Cu (orange symbols) and the liquid Cu covered with graphene (Gr) layer grown by chemical vapour deposition (blue symbols). The solid curves show the fit used to extract the electron density along the vertical direction. b) Electron density profiles from the experiment (brown) and simulation (red), as well as the corresponding species-resolved profiles of Cu (orange) and graphene (grey). Vertical dotted lines denote the Cu density inflection point and the peak of the graphene profile. The gap is derived as the distance between these two heights. The inset shows the simulation cell.