Abstract
The growth mechanism and properties of pristine, defective and doped two-dimensional (2D) materials,
including hexagonal boron nitride (hBN), are of significant interest for a wide variety of applications,
including electronics, sensors, coatings and catalysis. This thesis advances the understanding of hBN
growth mechanisms, investigates novel vacancy defects for environmental catalysis, and analyses water
molecule behaviour on hBN. Chemical vapour deposition (CVD) of hBN on ruthenium, using borazine
as a precursor, is a commonly used method for hBN synthesis. Through a combination of in situ
helium atom scattering measurements and Density Functional Theory (DFT) calculations, a nanoporous
intermediate of hBN is identified on Ru(0001), with the temperature-dependent growth mechanism
determined by a comprehensive evaluation of borazine reactions, combined with the construction of
a microkinetic model. These results reveal how site-specific preferences, selective dehydrogenation, and
energy barriers influence nanoporous structure formation, providing new insights for hBN synthesis.
Defects in hBN offer sites of novel reactivity; the potential of hBN defects for hydrogen generation by
dehydrogenation of ammonia at vacancy defects is explored. The reaction proceeds via a hydrogenated
vacancy intermediate with substrate-supported hBN, significantly enhancing H2 desorption. Further
investigation of the hydrogenated hBN vacancy revealed that this defect is capable of performing NOx
reduction. Our findings suggest feasible reaction conditions for converting NO2 into benign H2O,
demonstrating the potential for metal-free catalysis using hBN defects. Additionally, a combination of
DFT and ab initio molecular dynamics (AIMD) simulations was used to analyse the behaviour of a water
molecule on the surface of hBN and graphene materials with and without substrate. Comparing water
on hBN and graphene highlighted the impact of potential energy surface corrugation and vibrational
coupling on water diffusion, which is of interest for protective and anti-icing coatings. The research
presented in this thesis demonstrates hBN’s potential for environmental catalysis, H2 production, and
offers approaches for further exploration of nanomaterials