Synergistic bimetallic Ru-Pt catalysts for the low-temperature aqueous phase reforming of ethanol

Aqueous phase reforming (APR) of ethanol has been studied over a series of Ru and Pt catalysts supported on carbon and titania, with different metal loadings and particle sizes. This study proposed that, on both metals, ethanol is first dehydrogenated to acetaldehyde, which subsequently undergoes C-C cleavage followed by different paths, depending on the catalyst used. For instance, although monometallic Pt has high selectivity toward H-2 via dehydrogenation, it has a low efficiency for C-C cleavage, lowering the overall H-2 yield. Large Ru particles produce CH4 through methanation, which is undesirable because it consumes H-2. Small Ru particles have lower activity but higher selectivity toward H-2 rather than CH4. On these small particles, CO blocks low-coordination sites, inhibiting methanation. The combination of the two metals in bimetallic Ru-Pt catalysts results in improved performance, benefiting from the desirable properties of each Ru and Pt, without the negative effects of either. (c) 2018 American Institute of Chemical Engineers AIChE J, 65: 151-160, 2019