| AVS 54th International Symposium | |
| Renewable Energy Science & Technology Topical Conference | Wednesday Sessions |
| Session EN+SS+TF-WeM |
| Session: | Catalysis for Hydrogen Storage and the Hydrogen Economy |
| Presenter: | Y. Yang, Pacific Northwest National Laboratory |
| Authors: | Y. Yang, Pacific Northwest National Laboratory R. Disselkamp, Pacific Northwest National Laboratory C.T. Campbell, University of Washington C. Mims, University of Toronto, Canada D. Mei, Pacific Northwest National Laboratory J.H. Kwak, Pacific Northwest National Laboratory J. Szanyi, Pacific Northwest National Laboratory C.H.F. Peden, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
Formate hydrogenation was proposed to be the surface reaction channel forming methanol through reverse water gas shift by previous investigators [Chorkendorff et al., J. Vac. Sci. Technol. A, 10(4), 2277 (1992)]. The interconversion and decay of copper formates on a Cu/Gamma-Al2O3 catalyst are studied here using an apparatus that combines in-situ transmission-FTIR of adsorbed species and mass spectrometric detection of reactor effluent during transient kinetic analyses (transmission-FTIR/MS/TKA). At 573 K, ~ 2% CO and 0.07% methanol conversions were obtained by sending 2.5 bar H2:CO2 3:1 flow at 10 sccm through the reactor. It is also observed that at lower temperature, 353 K - 433 K, surface formate species are formed with the input feed stream as observed by IR. The kinetics of their transient reactivity (e.g., titration) are examined after switching to either a reducing (H2), oxidizing (2% N2O in He), or inert gas (He, Ar) feed stream. The kinetics of total formate decay at 306, 363, and 433 K under H2, He, or Ar gas exposure are observed to be comparable, suggesting that a thermal unimolecular desorption and not hydrogenation alone, is operative. However upon hydrogen exposure it is observed that within the broad formate IR band(s) there is internal species exchange which indicates two types of different formates are formed. Similar studies are presented for a SiO2 supported polycrystalline Cu sample to help identify the formate species. Methanol steam reforming on both samples were also studied for further understanding of the reverse reaction processes.