Multi-methodological analysis of hydrogen desorption from graphene

Abstract

Chemisorption of hydrogen on graphene has been extensively investigated in last decades, but the reported values of over several eV, depending on different factors, such as the local structural environment, substrates or previously bound hydrogen.In this work, we combine Temperature-Programmed Desorption experiments with simulations using empirical reactive force fields and Density Functional Theory calculations. We observe that desorption occurs through processes with different activation energies, which we are able to identify by analyzing simulation data and post-processing experimental ones through a procedure based on Arrhenius fit with feedback. The result is the assignment of experimentally observed desorption peaks to different desorption processes, namely desorption from isolated sp3 H, or couples of H in conformation cis or trans, or edge sp3 or sp2 H.The protocol we outline is generally applicable and might be particularly useful in more complex cases with larger multiplicity of desorption peaks.