Nan, Bing; Li, Lulu; Li, Yunan; Guo, Lingling; Du, Meng; Liu, Zhengwu; Tao, Xin; Tian, Chen; Liang, Zhenye; Zhang, Yanxing; Ma, Chao; Shen, Lu; Si, Rui; Li, Lina

APPLIED CATALYSIS B-ENVIRONMENT AND ENERGY

2023, 334, 1873-3883

Nan, Bing; Li, Lulu; Li, Yunan; Guo, Lingling; Du, Meng; Liu, Zhengwu; Tao, Xin; Tian, Chen; Liang, Zhenye; Zhang, Yanxing; Ma, Chao; Shen, Lu; Si, Rui; Li, Lina

Palladium (Pd) has been widely regarded as a high-performance catalyst for various oxidative reactions, however, the actual structure of active site remains controversial due to structural evolution under operation conditions. Herein, we prepared a series of bismuth (Bi)-doped silica-supported Pd catalysts and found a hydrogencontrolled structural reconstruction mechanism of palladium-bismuth oxide cluster to single atom alloy to efficiently catalyze low-temperature CO oxidation. The formation of PdxBiyOz clusters with unique Pd-O-Bi coordination structure could enhance the sinter-resistance ability of Pd species. This structural evolution of active site is clearly uncovered by in-situ XAFS results, in which metallic Bi-Pd shell gradually generates as the increase of reduction temperature without any metallic Bi-Bi bond. More importantly, PdBi1 single atom alloy exhibits a good CO oxidation activity with a CO2 production rate of 413 & mu;molCO2 & BULL;gPd- 1 & BULL;s- 1 at 100 degrees C and excellent catalytic stability. Density function calculation (DFT) results indicate that there are geometric and electronic effects between Bi and Pd atoms, which favor total linear-CO adsorption, activate CO and O2 molecules, and reduce the barrier for the formation of OO-CO intermediates in PdBi1 single atom alloy.