Effect of Iron compounds on hyperfine interactions and methane formation in the coal

Using Mossbauer spectroscopy and electron paramagnetic resonance, it is shown that Fe2+ and Fe3+ compounds in the coal increase the spin concentration in the carbon nanoclusters (aromatic area) and in the intercluster space (aliphatic medium). The Fe2+ compounds preferentially support the increase of dangled bonds in carbon nanoclusters, whereas the Fe3+ ones assist the formation of free radicals in the intercluster space. By means of the electron-nuclear double resonance, it is shown that hydrogen atoms are located in the both nanoclusters and intercluster space with the higher hydrogen content in the intercluster space. The saturation of dangled bonds by hydrogen and the increase in the fraction of free radicals serve as prerequisites for methane formation. In comparison with Fe3+, the Fe2+ compounds are more effective as catalysts for methane formation. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601741]