Photoassisted Reaction of H2 with CO2 Over Solid Catalysts.

摘要

Photo-promoted hydrogenation of CO2 at 1 atm total pressure over a number of catalysts was investigated. CO was the principal product of both the dark and photo-promoted reactions in the presence and absence of water vapor. The first batch of a Co-Mo-Al-Oxide preparation was the most active photocatalyst investigated, giving 0.35 molec. of CO per incident photon of white light and, in the presence of water vapor, a yield of CO equal to 10 times its concentration at thermal equilibrium. Studies of this system included the action spectrum for formation of CO and the dependence of rate on the CO2/H2 ratio, on temperature and on intensity of white light. The catalyst was a heterogeneous mixture of several phases. Subsequent batches of Co-Mo-Al-Oxide, prepared according to the original protocol, differed from the first batch in composition and were less active photocatalysts. Similar studies were carried out using pristine and platinized DeGussa P-25 Tio2 as catalyst.