Catalytic oxidation of Hg0 with O2 induced by synergistic coupling of CeO2 and MoO3

Based on Volcano plotting, the controlled combination of weak and strong bond strengths of a bimetallic catalyst has the potential to maximize the catalytic effect via the formation of intermediate bond strength between the reactant and the two different types of active sites. In this study, a rational design approach was adopted to couple MoO3 and CeO2 to maximize the catalytic oxidation of Hg-0 using oxygen as the oxidizing agent. It is found that CeO2 displayed a relatively strong bond strength with Hg-0 while MoO3 has relatively weak bond strength with Hg-0; the pre-doping of MoO3 results in the transformation of CeO2 from clusters to the form with additional exposed CeO2 (111) surface; the CeO2 and MoO3 show synergistic effect on the formation of Bronsted acid sites. Moreover, the results show that there is an overlap between the Hg-0 desorption region of MoO3 and the Hg-0 adsorption region of CeO2 (with adjusted optimum bond strength with Hg-0), which contributes to the catalytic reaction of Hg-0 by O-2. Therefore, this study reveals that the synergistic effects of the coupling of CeO2 and MoO3 induced the reaction between Hg-0 and O-2, which is otherwise difficult.