Figure 11.

IR spectroscopy reveals the thermal- and adsorbate-induced mobility of boron atoms in B-substituted zeolites. (a) IR spectra of a B-SSZ-13 material as-synthesized (gray) and after calcination at 500 °C (black). Reproduced with permission from ref (178). Copyright 2007 American Chemical Society. (b) Evolution of the background-subtracted IR spectra, in the ν(OH) region, of a B-SSZ-13 activated at 500 °C upon interaction with increasing dosages of NH₃ at room temperature (full coverage in dark green) and after heating at 100 °C in the presence of NH₃ followed by degassing (light green, vertically translated for clarity). (c) The same as in (b) in the 1500–800 cm^–1 region. (d) Schematic representation of the changes in the local structure around the B sites upon template removal, adsorption of NH₃, and further reaction with NH₃ at 100 °C. Reproduced with permission from ref (179). Copyright 2007 American Chemical Society.