Abstract
CuO is used as a catalyst or catalyst precursor in many chemical reactions that involve hydrogen as a reactant or product. A systematic study of the reaction of H2 with pure powders and films of CuO was carried out using in situ time-resolved X-ray diffraction (XRD) and surface science techniques. Oxide reduction was observed at atmospheric H2 pressures and elevated temperatures (150-300 °C), but only after an induction period. High temperature or H2 pressure and a large concentration of defects in the oxide substrate lead to a decrease in the magnitude of the induction time. Under normal process conditions, in situ time-resolved XRD shows that Cu1+ is not a stable intermediate in the reduction of CuO. Instead of a sequential reduction (CuO → Cu4O3 → Cu2O → Cu), a direct CuO → Cu transformation occurs. To facilitate the generation of Cu1+ in a catalytic process one can limit the supply of H2 or mix this molecule with molecules that can act as oxidant agents (O2, H2O). The behavior of CuO-based catalysts in the synthesis of methanol and methanol steam reforming is discussed in the light of these results.
Similar content being viewed by others
References
H. H. Kung, Transition Metal Oxides: Surface Chemistry and Catalysis (Elsevier, New York, 1989).
K. Klier, Adv. Catal. 31 (1982) 243.
J.-L. Li, T. Takeguchi and T. Inui, Appl. Catal. A139 (1996) 97.
D. S. Newsome, Catal. Rev. Sci. Eng. 21 (1980) 275.
B. A. Peppley, J. C. Amphlett, L. M. Kearns and R. F. Mann, Appl. Catal. A179 (1999) 31.
T. L. Reitz, P. L. Lee, K. F. Czaplewski, J. C. Lang, K. E. Popp and H. Kung, J. Catal. 199 (2001) 193.
W.-P. Dow and T.-J. Huang, Appl. Catal. A141 (1996) 17.
C. T. Campbell, K. A. Daube and J. M. White, Surf. Sci. 182 (1987) 458.
J. Nakamura, J. M. Campbell and C. T. Campbell, J. Chem. Soc. Faraday Trans. 86 (1990) 2725.
C. T. Campbell, Adv. Catal. 36 (1989) 1.
C. J. Giang, D. L. Trimm, M. S. Wainwright and N. W. Cant, Appl. Catal. 97 (1993) 145.
B. A. Peppley, J. C. Amphlett, L. M. Kearns and R. F. Mann, Appl. Catal. A179 (1999) 31.
M. M. Gunter, T. Ressler, R. E. Jentoft and B. Bems, J. Catal. 203 (2001) 133.
T. L. Reitz, P. L. Lee, K. F. Czaplewski, J. C. Lang, K. E. Popp and H. H. Kung, J. Catal. 199 (2001) 193.
PDF # 41-0254, JCPDS Powder Diffraction File, Int. Center for Diffraction Data, Swarthmore, PA, 1989.
PDF # 33-0480, JCPDS Powder Diffraction File, Int. Center for Diffraction Data, Swarthmore, PA, 1989.
PDF # 05-0667, JCPDS Powder Diffraction File, Int. Center for Diffraction Data, Swarthmore, PA, 1989.
W.-P. Dow, Y.-P. Wang and T. J. Huang, J. Catal. 160 (1996) 155.
W.-P. Dow and T. J. Huang, Appl. Catal. A141 (1996) 17.
M. Fernandez-Garcıa, I. Rodrıguez-Ramos, P. Ferreira-Aparicio and A. Guerro-Ruiz, J. Catal. 178 (1998) 253.
M. K. Neylon, C. Marshall and J. Kropf, to be published.
M. S. W. Vong, P. A. Sermon and K. Grant, Catal. Lett. 4 (1990) 15.
P. Norby and J. Hanson, Catal. Today, 39 (1998) 301; and references therein.
T. Ressler, R. E. Jentoft, J. Wienold, M. M. Günter and O. Timpe, J. Phys. Chem. B104 (2000) 6360.
J. A. Rodriguez, J. C. Hanson, A. Frenkel, J.-Y. Kim and M. Perez, J. Am. Chem. Soc. 124 (2002) 346.
S. Poulston, P. M. Parlett, P. Stone and M. Bowker, Surf. Interf. Anal. 24 (1996) 811.
J. A. Rodriguez and J. Hrbek, J. Vac. Sci. Technol. A12 (1994) 2140.
J. G. Chen, Surf. Sci. Reports 30 (1997) 1.
P. J. Chupas, M. F. Ciraolo, J. C. Hanson and C. P. Grey, J. Am. Chem. Soc. 123 (2001) 1694.
B. S. Clausen, G. Steffensen, B. Fabius, J. Villadsen, R. Freidenhans and H. Topsoe, J. Catal. 132 (1991) 524.
A. P. Hammersely, S. O. Svensson and A. Thompson, Nucl. Instrum. Methods Phys. Res. 346 (1994) 321.
J. A. Rodriguez and M. Kuhn, J. Phys. Chem. 99 (1995) 9567.
J. Y. Kim, J. A. Rodriguez, J. C. Hanson, A. I. Frenkel and P. L. Lee, to be published.
V. E. Henrich and P. A. Cox, The Surface Science of Oxides (Cambridge University Press, Cambridge, UK, 1994).
B. Delmon in: Handbook of Heterogeneous Catalysis, eds. G. Ertl, H. Knozinger and J. Weitkamp (VCH-Wiley, New York, 1997) p. 264.
J. A. Rodriguez, J.-Y. Kim, J. C. Hanson and J. L. Brito, Catal. Lett. 82 (2002) 103.
R. P. Furstenau, G. McDougall and M. A. Langell, Surf. Sci. 150 (1985) 55.
J. G. Chen, D. A. Fischer, J. Hardenbergh and R. B. Hall, Surf. Sci. 279 (1992) 13.
To be published.
R. G. Herman, K. Klier, G. W. Simmons, B. P. Finn, J. B. Bulko and T. P. Kobylinski, J. Catal. 56 (1979) 407.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rodriguez, J.A., Kim, J.Y., Hanson, J.C. et al. Reduction of CuO in H2: In Situ Time-Resolved XRD Studies. Catalysis Letters 85, 247–254 (2003). https://doi.org/10.1023/A:1022110200942
Issue Date:
DOI: https://doi.org/10.1023/A:1022110200942