(562g) Controlled expansion of pores in graphene at the Å-scale by CO2
AIChE Annual Meeting
2022
2022 Annual Meeting
Materials Engineering and Sciences Division
Two-Dimensional Materials and Thin Films
Wednesday, November 16, 2022 - 5:00pm to 5:15pm
A controlled manipulation of graphene edges and vacancies is desired for molecular separation, sensing and electronics applications. Unfortunately, available etching methods always lead to vacancy nucleation making it challenging to control etching. Herein, we report CO2-led controlled etching down to 2-3 Å per minute while completely avoiding vacancy nucleation. This makes CO2 a unique etchant for decoupling pore nucleation and expansion. We show that CO2 expands the steric-hindrance-free edges with an activation energy of 2.71 eV, corresponding to the energy barrier for the dissociative chemisorption of CO2. We demonstrate the presence of an additional configurational energy barrier for nanometer-sized vacancies resulting in a significantly slower rate of expansion. Finally, CO2 etching is applied to map the location of the intrinsic vacancies in the polycrystalline graphene film where we show that the intrinsic vacancy defects manifest mainly as grain boundary defects where intragrain defects from oxidative etching constitute a minor population.
Reference
(1) Rezaei, M.; Villalobos, L. F.; Hsu, K.-J.; Agrawal, K. V. Demonstrating and Unraveling a Controlled NanometerâScale Expansion of the Vacancy Defects in Graphene by CO 2. Angew. Chemie Int. Ed. 2022, 61 (18), e202200321.