Effects of crystal size on methanol to hydrocarbon conversion over single crystals of ZSM-5 studied by synchrotron infrared microspectroscopy

DOI: 10.1039/D0CP00704H

Authors: Ivalina B. Minova (University of St Andrews) , Santhosh K. Matam (UK Catalysis Hub, Research Complex at Harwell; Cardiff University) , Alex Greenaway (EaStCHEM School of Chemistry, Purdie Building, St Andrews) , C. Richard A. Catlow (UK Catalysis Hub, Research Complex at Harwell; Cardiff University; University College London) , Mark D. Frogley (Diamond Light Source) , Gianfelice Cinque (Diamond Light Source) , Paul A. Wright (University of St Andrews) , Russell F. Howe (University of Aberdeen)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Chemistry Chemical Physics , VOL 44

State: Published (Approved)
Published: March 2020
Diamond Proposal Number(s): 13725 , 16257 , 18680 , 20906

Abstract: Operando synchrotron infrared microspectroscopy (OIMS) was used to study the conversion of methanol over coffin-shaped HZSM-5 crystals of different sizes: large (∼250 × 80 × 85 μm3), medium (∼160 × 60 × 60 μm3) and small (∼55 × 30 × 30 μm3). The induction period, for direct alkene formation by deprotonation of surface methoxy groups, was found to decrease with decreasing crystal size and with increasing reaction temperature. Experiments with a continuous flow of dimethylether showed that evolution of the hydrocarbon pool and indirect alkene formation is also strongly dependent on crystal size. These measurements suggest that the hydrocarbon pool formation and indirect alkene generation should be almost instantaneous at reaction temperatures used in practical catalysis with crystal sizes typically ∼1 μm3.

Subject Areas: Chemistry


Instruments: B22-Multimode InfraRed imaging And Microspectroscopy