Catalytic Conversion of Ethanol to Hydrogen Using Combinatorial Methods

Ethanol is a globally available renewable source for hydrogen production for fuel cell applications. Prior research in this area focused on steam reforming of ethanol at relatively high temperatures ( T > 500 °C), where carbon deposition and heat integration create operational problems. Combinatorial catalysis, an effective methodology for the accelerated discovery and optimization of functional materials, has been applied for the discovery of low-temperature catalysts for the production of hydrogen from ethanol. Libraries of catalytic materials were prepared by impregnating porous pellets of γ-Al 2 O 3, SiO 2, TiO 2, CeO 2, and Y−ZrO 2 with individual aqueous salt solutions of 42 elements from the periodic table at 4 different loadings in the range 0.5−5 wt %. Ethanol steam reforming activities and H 2 selectivities of these 840 distinct materials were then evaluated using a computerized array channel microreactor system and mass spectrometry. Catalysts were screened under identical operating conditions of 300 °C, 1 atm, and a GHSV of 60 000 h -1 using a feed gas composition of 2% C 2 H 5 OH and 12% H 2 O in a helium carrier gas. This systematic investigation, completed over a period of several months, both provided confirmatory results and produced new leads of superior catalytic materials. Pt/TiO 2 and Pt/CeO 2 were the most significant new leads, both of which gave the highest ethanol conversions (+90%) and hydrogen selectivities (∼30%) at 300 °C among all the single component catalytic materials explored.