Energy & Fuels, Vol.26, No.7, 4405-4412, 2012
Solid-State NMR Studies of Fossil Fuels using One- and Two-Dimensional Methods at High Magnetic Field
We examine the opportunities offered by advancements in solid-state NMR (SSNMR) methods, which increasingly rely on the use of high magnetic fields and fast magic angle spinning (MAS), in the studies of coals and other carbonaceous materials. The sensitivity of one- and two-dimensional experiments tested on several Argonne Premium coal samples is only slightly lower than that of traditional experiments performed at low magnetic fields in large MAS rotors, since higher receptivity per spin and the use of H-1 detection of low-gamma nuclei can make up for most of the signal loss due to the small rotor size. The advantages of modern SSNMR methodology in these studies include improved resolution, simplicity of pulse sequences, and the possibility of using J-coupling during mixing.