Defective Nb2O5-supported Pt catalysts for CO oxidation: Promoting catalytic activity via oxygen vacancy engineering

Abstract

© 2019 Elsevier Inc.We introduced oxygen vacancies into Nb2O5 via thermal treatment at 700 °C under oxygen-deficient conditions for different lengths of time. Niobia-supported Pt catalysts were subsequently synthesized using the wet impregnation method with the fabricated Nb2O5. The catalytic activity of the synthesized catalysts for CO oxidation exhibited a significant increase from that obtained for a counterpart having the Nb2O5 support treated under saturated oxygen conditions (i.e., in air). Moreover, increasing the number of oxygen vacancies was found to increase the catalytic activity. At 150 °C, the TOF calculated for the catalyst with the most oxygen vacancies was 0.36 s−1, which was much higher than that obtained from the catalyst possessing the fewest oxygen vacancies (0.05 s−1). Systematic characterization of the synthesized catalysts revealed the crucial impact of oxygen vacancies and active lattice oxygen on the enhancement of catalytic activity