Interaction of atomic hydrogen with amorphous carbon (a-C) grown on Cu substrate has been explored for the first time. Here we report the investigations performed at 600 degrees C substrate temperature. This research finds its significance in understanding the role of atomic hydrogen in establishing the growth of graphene at low substrate temperatures. After exposing the a-C film to atomic hydrogen for various durations, we observe that atomic hydrogen reacts with the a-C film on Cu surface leading to the formation of nanographene. With the increase in exposure time, graphene nuclei grow in number and dimension, forming a polycrystalline network of nanographene domains. High resolution transmission electron microscope images reveal this structural transformation, which has also been substantiated by Raman spectra. The chemical compositional analysis is performed using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Based on these observations, we explain the probable mechanism which elucidates the role of atomic hydrogen in transforming a-C into sp(2) hybridized hexagonal structures in the presence of Cu at 600 degrees C. (C) 2018 Elsevier B.V. All rights reserved.