Realizing the high loading amount of active Cu on Al2O3 to boost its CO catalytic oxidation

Catalytic oxidation of carbon monoxide (CO) by Cu/Al 2 O 3 has garnered increasing interest in recent years due to its promising application prospects. Numerous investigations conducted on the Cu/Al 2 O 3 system, but its catalytic performance for CO oxidation is still not as promising as that of precious metal catalysts. Increasing the loading amount of the active Cu on Al 2 O 3 surface is a feasible method for improving its activity. However, with the increase of Cu loading, the agglomeration and enlargement of Cu particles is inevitable, which reduces the active Cu amount. Therefore, the utilization rate of Cu atoms is not high and the catalytic performance often can not further rise. Enhancing active Cu loading amount as high as possible is a prerequisite to further enlarge the activity of Cu/Al 2 O 3 catalyst. Herein, self-synthesized Al 2 O 3 nanofibers (Al 2 O 3 -nf) with high specific surface area and abundant penta-coordinated aluminum (Al V ) are used as the support to maximize the Cu loading amount by chemical vapor deposition (CVD). And commercially available α-Al 2 O 3 is used for comparative experiment. The high specific surface area could make Cu high dispersion on Al 2 O 3 , even at 20 wt% Cu loads, which is beneficial to high concentration load of active Cu. The catalytic activity of Cu/Al 2 O 3 -nf-CVD gradually increases with the increase of Cu loading from 2 wt% to 20 wt%, exhibiting a clear linear correlation with the surface content of Cu 0 on the catalyst. Meanwhile, this result confirms that Cu 0 plays a crucial role in CO oxidation of Cu/Al 2 O 3 . However, commercial α-Al 2 O 3 reaches its highest activity when the Cu load is 5%, and then its activity begins to decrease due to the agglomeration of particles. Moreover, Cu/Al 2 O 3 -nf-CVD also exhibits remarkable thermal stability for CO oxidation. This work highlights a new strategy to synthesis of high Cu loading amount, high activity and thermostable Cu/Al 2 O 3 catalyst for low-temperature oxidation of CO.