La-Ce-O modified Rh-LaFeO3 on SiO2 for direct ethanol synthesis from syngas

A new catalyst for direct ethanol synthesis (DES) from syngas composed of Rh nanoparticles (NPs) highly dispersed on La-Ce-O modified LaFeO 3 which was loaded on SiO 2 support was studied in this work. Over the best catalyst 40.6 % of the reacted CO could be directly converted into ethanol with CO conversion of 14.2 % at 250 °C, 3 MPa and GHSV of 3900 mL (g cat h) −1 . The results indicated that adding cerium into LaFe 0.5 Rh 0.5 O 3 /SiO 2 resulted in La 1-x Ce x Fe 0.5 Rh 0.5 O 3 /SiO 2 , the incorporation of Ce effectively regulated the interface electronic states of Rh NPs . The well matched catalyzing process by the active sites of Rh 0 , Rh + (or Rh δ+ ) and the oxygen vacancies on the surface of LaFeO 3 , of those, Rh 0 dissociatively adsorbed CO and the latter two associatively adsorbed CO could effectively improve the activity and selectivity for DES. Moreover, the interaction of La-Ce-O and LaFeO 3 strengthened the CO adsorption on the oxygen vacancies on LaFeO 3 , which improved the capacity of assistance in activating CO associatively, thus further increasing the selectivity to ethanol. The catalyst exhibited excellent resistance to carbon deposition and sintering, attributing to the small size of Rh NPs and the carbon eliminating effect of La 2 O 3 and oxygen vacancies on the surface of LaFeO 3 .