Probing Ethanol Dehydration with Silicon-Doped Aluminophosphates under Realistic Working Conditions Using Inelastic Neutron Scattering and Infrared Measurements

Vibrational techniques such as infrared spectroscopy and inelastic neutron scattering offer complementary information into reagent–catalyst interactions. While infrared spectroscopy emphasizes modes with strong changes in dipole moment, inelastic neutron scattering highlights vibrational modes, which displace hydrogen atoms, independent of the effect on dipole moment. In this study, findings from these techniques were combined to probe the interactions of ethanol with two distinct silicon-doped aluminophosphate frameworks, enabling direct comparisons on their reactivity and catalytic mechanisms for ethanol dehydration. By mimicking actual reaction conditions and correlating with reactivity data, these in situ and operando measurements highlighted the different behaviors of the two catalysts. Furthermore, detailed computational calculations supported the assignment of spectral features, providing a detailed understanding of ethanol dehydration over these materials.