Atomic-scale investigation of the role of supports in nanocrystal growth.

Metal nanoparticles supported on solid materials form the cornerstone of industrial catalysis, where metal-support interactions play a critical role in tuning the chemistry of active sites. Beyond their influence post-synthesis, supports exert a profound impact during the initial stages of nanocrystal growth, significantly affecting the catalytic performance. However, a detailed atomic-level understanding of these processes remains elusive. Herein, we investigate the influence of graphene oxide (GO) supports on the growth dynamics of metal nanocrystals using in situ transmission electron microscopy (TEM). Using Cu nanocrystals as a model system, we demonstrate that GO induces anisotropic growth by modulating the surface free energy of specific crystallographic facets through oxygen-functional groups, as revealed by density functional theory (DFT) calculations. Complementary in situ electron energy loss spectroscopy (EELS) measurements confirm that such anisotropic growth leads to surface charge enrichment, which in turn promotes C-C coupling during the electrocatalytic carbon dioxide reduction reaction (CO2RR), thereby enhancing the production rate of C2 products. Furthermore, the generality of this support-induced anisotropic growth was validated for a range of metals, including Au, Ag, Pd, Pt, and Co. Collectively, these findings provide novel insights into metal-support interactions and offer a promising strategy for optimizing catalytic performance through the deliberate control of nanocrystal growth pathways.