A process to reproduce repeatable 2D material-based hierarchical enhanced surface area structures

Abstract

We report a repeatable method for fabrication of a 2D material-based hierarchical enhanced surface area structures (HESAS), which relies on a titanium substrate as the base for nucleation and growth and a titania-acid solution. Since the initial documentation of these formations in 2020, numerous experimental iterations have ensued, culminating in the establishment of a straightforward, replicable procedure for their fabrication. Subsequent to the inaugural report, this manuscript offers a comprehensive overview of the synthesis procedure and structural attributes. Furthermore, it summarizes various pivotal discoveries attained during the course of process refinement, including the significance of substrate preparation in particle synthesis. Specifically, the removal (or lack thereof) of the oxide layer dictates whether (or not) the 2D building blocks form, which corroborates that the composition and level of reactivity of the base surface—where the heterogenous nucleation events take root—appear to impact the ability for crystallization to occur. Nonclassical nucleation and crystallization theories could explain some of the observed patterns in the fabricated HESAS. This report briefly discusses some of the factors which affect supersaturation for the chosen synthesis system and the critical role supersaturation plays in the development of HESAS. Future work should include advancing understanding on the kinetics (and hence dynamic behavior) of the supersaturation parameters; this will be critical to develop controlled fabrication protocols of HESAS, enabling their broader adoption.