Preparation and Catalytic Performance of Vanadium-Molybdenum Catalysts Supported on TiO2 Supports from Different Sources

Selective catalytic reduction (NH3-SCR) technology is the predominant technique for industrial flue gas denitrification, with its improvement dependent on the development of highly efficient catalysts. As the most widely employed support for vanadium-based DeNOx catalysts, TiO2 exerts significant influences on the dispersion state of active species and the catalytic performance through its physicochemical properties. In this work, three VMoOx@TiO2 catalysts were prepared using three different Ti precursors. Multiple characterization techniques were employed to systematically investigate the effects of different support origins on the surface morphology, acid-base properties, and redox performance of the catalysts. The results revealed that the tetrabutyl titanate-derived support possesses the largest specific surface area and most abundant mesoporous structure, facilitating highly dispersed V and Mo species. XPS analysis demonstrated that V4+ proportion increased from 38.9% to 56.6% and Mo6+ proportion increased from 50.2% to 78.9% from Catalyst A to C, attributed to enhanced V–O–Mo bridge bond electron transfer. DFT calculations confirmed that the electron transfer driving force on Catalyst C was the largest, and the NH3 adsorption energy at Lewis acid sites reached −102.4 kJ/mol, significantly exceeding those of Catalysts A and B. The potential energy surface analysis revealed that the rate-determining step exhibited the lowest energy barrier on Catalyst C, consistent with its superior DeNOx activity: it reaches complete NO conversion at 350 °C and displays optimal sulfur resistance. This study integrates experimental characterization with theoretical computation to establish the structure–activity relationship between TiO2 support properties and the DeNOx performance of vanadium-molybdenum catalysts, providing both theoretical guidance and a scientific basis for the rational design of high-performance SCR DeNOx catalysts.