Modulation of Proton Permeation through Defect Engineering in Hexagonal Boron Nitride

Abstract

Proton tunneling through 2D materials such as graphene and hexagonal boron nitride (hBN) was demonstrated experimentally in 2014 and has garnered significant attention in the field of nanotechnology due to its potential applications in energy storage, fuel cells, catalysis, and hydrogen isotope separation. Furthermore, engineering defects on similar 2D materials have also contributed to advancing the realization of these applications. Here, we investigate proton tunneling through hBN to improve our understanding of how engineering defects in hBN can be used to modulate proton permeation. Specifically, we employ a 1D transition state model to simulate the permeation of protons through both pristine and defective hBN. This model utilizes the energy barriers of protons permeating across hBN to estimate transmission coefficients, tunneling probabilities, and fluxes. To enhance the accuracy of our flux estimates, we take into account the zero-point energies of protons in water and discuss a method to increase the proton flux through hBN by exciting protons vibrationally. After the incorporation of zero-point energies, our flux calculations indicate that the isotopes of hydrogen ions can be separated at low temperatures using engineered defects in hBN. The results of this study provide insights into engineering defects on hBN, which can lead to the development of membranes with high proton conductivity while remaining impermeable to other species. These findings have significant implications for the design and optimization of advanced materials for various nanoscale applications.