Low CO generation on tunable oxygen vacancies of non-precious metallic Cu/ZnO catalysts for partial oxidation of methanol reaction

A simple and inexpensive method is proposed to modulate oxygen vacancies on the non-precious metallic CuZn-based catalyst surface. The identification and quantification of these oxygen vacancies on vZ (ZnO containing oxygen vacancies) and the catalytic activities of CvZ (Cu on ZnO containing oxygen vacancies, ca. 30 wt.% Cu and 70 wt.% Zn) during partial oxidation of methanol (POM) reaction are discussed. The vZ was calcined in a nitrogen atmosphere at various temperatures (450 degrees C, 500 degrees C and 550 degrees C), and catalytic activities of CvZ catalysts prepared in deposition precipitation (DP) and co-precipitation (CP) and CZr (Cu on ZrO2, ca. 30 wt.% Cu and 70 wt.% Zr) catalysts were performed. The efficiency of both CP-CvZ-450 and DP-CvZ-450 catalysts are excellent with 100% of C-MeOH and 95% of F-H2 at 250 degrees C, and 70% of C-MeOH and >75% F-H2 at 150 degrees C. Significantly, F-CO was kept at 0-4% at T < 250 degrees C with better stability for DP-CvZ-450 catalyst, as well. Moreover, a CO-free situation could be achieved for both DP-CvZ-500 and DP-CvZ-550 which contain more oxygen vacancies. These oxygen vacancies on the surface: enhanced an affinity for adsorbing reactant oxygen atoms; induced decomposition of intermediates species, and; can even catalyze CO oxidation at a lower temperature. (C) 2013 Elsevier B.V. All rights reserved.