NMR is extensively used to investigate both homogeneous and heterogeneous catalysts. In homogeneous catalysis, NMR can track changes in the chemical environment of nuclei to study reaction mechanisms and intermediates. For heterogeneous catalysis, techniques such as solid-state NMR are employed to study surfaces and interfaces. For instance, Magic Angle Spinning (MAS) NMR is used to average out anisotropic interactions, providing high-resolution spectra of solid catalysts.