Photoassisted Reaction of H2 with CO2 Over Solid Catalysts.
Abstract
The dark and photoassisted reactions of CO2 with H2 over alpha-Fe2O3, Zn-Fe-Oxide, Co-Mo-Al-oxide, Co-Mo-Al-oxide, Co-Mo-Ti-oxide, platinized La-Ni-oxide and platinized SrTiO3 have been investigated in the absence and presence of water vapor. Illumination was by a Hg-Xe-lamp at wavelengths above 350nm. The incident light flux, measured by ferrioxalate actinometry, was (1.02 + or - 0.08) x 10 to the 17th power photons/sec. Reactants in the ratio of H2:CO2 = 2:1 were passed once over dry films of powdered catalysts at 30 C and latm with contact times of 1/2 or 1min. Products were analyzed by gas chromatography. No reaction took place in the absence of catalyst. Catalyzed rates of production of products were constant over the 22hr periods investigated. CO was the only product obtained in significant amounts in the dark. Under illumination, rates of formation of CO increased by a factor of 2 - 4.5. CH4 was the only other product of the photoassisted reaction in the absence of water vapor, with yields less than 0.2 mole% of those of CO. In the presence of water vapor (3 mole% of supplied CO2), formic acid was produced at rates up to 19 mole% the rate of formation of CO, along with minor amounts of CH4, CH2O and CH3OH, all produced at rates less than 0.2 mole% that of CO. The highest photoassisted yields were obtained over Co-Mo-Al oxide, with efficiency of conversion of incident photons into products around 0.35 molecule of product/incident photon. The corresponding estimated quantum yield was 1 molecule of product/absorbed photon.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 14, 1986
- Accession Number
- ADA174581
Entities
People
- B. I. Rubio
- K. M. Vijayakumar
- Norman N. Lichtin
Organizations
- Boston University