To be support or promoter: the mode of introducing ceria into commercial V2O5/TiO2 catalyst for enhanced Hg0 oxidation

Ce-modified commercial vanadium-based catalysts are still in a rapid development stage in terms of optimizing Hg0 oxidation performance. Due to the universal property of ceria, it can act as either support or promoter to supported vanadium-based catalysts. However, the introduction mode of Ce on the Hg0 oxidation is still un-clarified. Herein, introducing Ce to vanadium-based catalysts as a promoter (VCe/Ti) plays a more effective role in the Hg0 oxidation than only doping Ce into TiO2 support (V/CeTi). It is revealed that the strong interaction between V and Ce increases the orbital hybridization, and reduces the lowest unoccupied molecular orbital (LUMO) of V, which is conducive to adsorbing and activating HCl. The excellent performance of the VCe/Ti catalyst can be ascribed to its superior redox ability, stronger HCl adsorption capacity, abundant surface oxygen vacancies, and the redox equilibrium (Ce3+ + V5+<-> Ce4++ V4+), which improves electron transfer, and thus the catalytic activity. This work provides the potential application of Ce-modified V-based catalysts for the simul-taneous control of NOx and Hg0 in stationary sources.

Automated summary

Ce-modified commercial vanadium-based catalysts are still being rapidly developed to optimize Hg0 oxidation performance. The introduction mode of Ce on Hg0 oxidation is still unclear. Introducing Ce as a promoter (VCe/Ti) to vanadium-based catalysts plays a more effective role in Hg0 oxidation than doping Ce into TiO2 support (V/CeTi). The excellent performance of the VCe/Ti catalyst is attributed to its redox ability, HCl adsorption capacity, surface oxygen vacancies, and redox equilibrium, which improve electron transfer and catalytic activity. This work offers the potential application of Ce-modified V-based catalysts for simultaneous control of NOx and Hg0 in stationary sources.