PNNL

Abstract

Two-dimensional (2-D) conductive metal-organic frameworks (MOF) represent a unique class of electrode materials with high capacity and power density. Understanding molecular mechanisms and pathways for heterogeneous nucleation of 2-D p-conjugated MOFs is highly desirable for controlling the structure and properties of conductive MOFs on solid substrates. Herein, we report our systematic study of nucleation and growth of 2-D p-conjugated Ni-CAT-1 MOFs on highly oriented pyrolytic graphite and copper substrates. We discovered that the nucleation density and structure of the MOF film can be controlled by varying substrate interactions with the organic linker. Specifically, p-p interactions between the linker and the highly oriented pyrolytic graphite dictate lower nucleation density and defects within the film, whereas p-metal interactions between the linker and the copper substrate dictate faster nucleation, higher nucleation densities, and the presence of extended defects. These studies reveal the key mechanism for Ni-CAT-1 nucleation on different surfaces and provide insights into interfacial control over the growth of other 2-D p-conjugated MOF films on solid substrates to inform synthesis of functional materials.