Structural analysis of reduced molybdenum oxide catalyst for light-assisted reverse water-gas shift reaction.

Abstract

Reduced molybdenum oxide (H_xMoO_3-y) obtained through hydrogen reduction of MoO₃ has two distinctive properties. One is abundant oxygen vacancies and another is strong absorption of visible light. The application of these features to the catalytic reactions is being investigated. In this study, the structures of the catalyst under the reaction conditions were investigated by using in-situ XAFS and in-situ UV-vis measurements. The activity of the reverse water gas shift reaction was enhanced depending on the amount of oxygen vacancies, and in-situ XAFS measurement results suggest that the reaction proceeds via a reversible redox behavior of oxygen vacancies. In addition, the activity of the reaction under visible light irradiation increased more than two-fold, and the in-situ UV-vis measurement results suggest that the increase in the visible light region is due to the plasmon-originated light absorption.