CuO/TiO₂/Ti Monolithic Catalysts for Low-Temperature CO Oxidation

Abstract

In this innovative work, a series of CuO/TiO 2 /Ti monolithic catalysts were successfully synthesized using a scalable multistep method involving plasma electrolytic oxidation (PEO) and hydrothermal processes. The results revealed that the growth of CuO nanostructures can be controlled by varying the hydrothermal time. Specifically, the CuO/TiO 2 /Ti monolithic catalyst, obtained through a 1 h hydrothermal reaction (HR1), resulted in fine particle size, good dispersion, large specific surface area, especially sufficient Cu + active sites, high oxygen vacancy concentration, and excellent redox ability. These attributes collectively ensured the efficient catalytic CO oxidation activity of the prepared catalysts. Moreover, the as-synthesized HR1 catalyst exhibited a remarkable ability to achieve 100% conversion at ∼107 °C, indicating enormous potential as a substitute for conventional noble metal catalysts. Furthermore, this study elucidates that the CO, adsorbed on the Cu + sites, is oxidized by the lattice oxygen of CuO. The O 2 present in the feed gas plays a crucial role in replenishing the oxygen vacancies created during this process, thereby facilitating efficient recycling of the catalytic reaction. The presented mechanism analysis of CuO/TiO 2 /Ti monolithic catalysts for low-temperature CO oxidation provides a theoretical basis for the design of catalysts.