Construction of functionalized Pt-O-S bridge on Pt/TiO2 simultaneously enhancing the catalytic activity and sulfur resistance for CO oxidation

Removing industrial source CO through catalytic oxidation and providing heat for denitrification units have significant economic and environmental benefits. Sulfur poisoning of catalysts is the bottleneck to stabilize the system operation. To overcome this problem, we fabricated sulfate modified Pt/TiO 2 by appropriate NH 4 HSO 4 deposition, which survived in the SO 2 environment with the concentration as high as 1000 ppm SO 2 , and exhibited an outstanding stability with over 90% CO conversion at 200 °C for 500   h under a typical steel sintering flue gas condition. Experimental and theoretical explorations confirmed that the electronic structure of PtO x clusters was optimized through Pt-O-S bridges after sulfate modification. The O 2p band center closer to the Fermi level and the smaller energy difference between Pt 5d and O 2p band centers led to more active lattice oxygen of PtO x clusters. The more stable π back bonding between Pt 5d and CO 2p and weaker hybridization between Pt and the π⁎ (Ssp2-Osp2)2 orbital of SO 2 indicated enhanced CO adsorption while weakened SO 2 adsorption on Pt sites. The above factors simultaneously improved the low-temperature activity and sulfur resistance for CO oxidation over sulfate modified Pt/TiO 2 . This work provides new insights for the design of sulfur-resistant catalysts and the understanding on the effect of sulfates on catalytic activity.