Operando Molecular Spectroscopy during Catalytic Biomass Pyrolysis
Доклады на конференциях
We have developed an operando Raman/IR-MS spectroscopy system for catalytic biomass pyrolysis that simultaneously monitors catalyst structure, biomass structure, surface reaction intermediates, coking, char formation, and over 40 major gas phase pyrolysis products (determined by GC-MS). Model supported 1-10% Al2O3/SiO2 catalysts were synthesized and characterized (in situ Raman, in situ IR, and high field (21.1T) ex situ dehydrated 27Al NMR spectroscopy). The chemical nature (Brönsted or Lewis acid sites; BAS or LAS) of specific surface AlOx acid sites was determined from in situ IR-CO adsorption and DFT calculations. These well-defined catalysts were employed during the catalytic pyrolysis of cellulose, hemicellulose (xylan), lignin, their monomers (glucose and xylose), and woody biomass to determine correlations between specific value-added chemicals, required acid site nature, and surface AlOx active site coordination. Results were also compared to popular HZSM-5 catalysts (Zeolyst) with different Si/Al ratios (15 to 140).