Operando spectroscopy lights combustion and deactivation
We have used in-situ spectroscopic techniques coupled with temperature programmed oxidation in order to characterize the coke deposited on a Ni/La2O3‐αAl2O3 catalyst used in the steam reforming of bio‐oil. Those techniques are FTIR spectroscopy with mass spectrometry (MS), and Raman spectroscopy. At the same time, we have combined these results with thermogravimetry (TG), modulated thermogravimetry (MTG), and differential scanning calorimetry (DSC).
The steam reforming of bio‐oil, aiming hydrogen, was carried out in a reactor equipment with two steps in series, comprising bio‐oil thermal treatment (500 °C) and subsequent reforming in a fluidized bed reactor (550–700 °C; and steam‐to‐carbon ratio, 1.5–6).
Our results identify: (i) an encapsulating coke with aliphatic nature placed in the most superficial layers; (ii) an encapsulating coke with higher aromatic nature in inner layers; (iii) the most superficial layers of a filamentous coke, further from active sites and with a more carbonized structure compared to encapsulating coke; and (iv) an innermost and mainly polyaromatic filamentous coke with a low oxygenates content.
§ Ochoa, A., Valle, B., Resasco, D.E., Bilbao, J., Gayubo, A.G., Castaño, P., TPO Coupled with In-Situ Techniques Reveal Nature and Location of Coke Deposited on a Ni/La2O3-αAl2O3Catalyst in the Steam Reforming of Bio-Oil, ChemCatChem, 10 (2018) 2311-2321. DOI: 10.1002/cctc.201701942.
