Surface Properties of Rh/AlPO₄ Catalyst Providing High Resistance to Sulfur and Phosphorus Poisoning

Abstract

A rhodium catalyst supported on AlPO4 exhibited a much higher resistance to sulfur and phosphorus poisoning compared with a reference catalyst (Rh/Al2O3). The acidic surface of AlPO4 was effective in preventing the adsorption of sulfur oxides (SO2), whereas Lewis acid/base sites on Al2O3 favored SO2 adsorption followed by the formation of sulfite, leading to deterioration of the activity of Rh/Al2O3 for the model NO–CO–C3H6–O2 reaction. Similarly, the AlPO4 support suppressed the extent of phosphorus poisoning caused by dimethylphosphite (DMP) (CH3O)2POH, which was used as a model phosphorus source. A greater amount of inactive phosphate overlayers were deposited from the gas feed containing DMP and O2 on Rh/Al2O3 than Rh/AlPO4 because of the reaction between P2O5 vapors and Al2O3. Consequently, the active Rh surface was covered to a greater extent for Rh/Al2O3 than Rh/AlPO4.

Lean NOx reduction over Rh/ZrP2O7 catalyst under steady-state and perturbation conditions

“…The catalytic activity and stability of catalysts is strongly dependent on the interactions at the metal-support interface. We have previously studied various metal phosphates, such as AlPO 4 , ZrP 2 O 7 , and LaPO 4 , as thermally stable supports for Rh catalysts [11][12][13][14][15][16][17][18][19]. These materials produce optimum interactions with the Rh species via Rh O P bonding and enable high dispersion of Rh anchored onto the phosphate unit on the surface [13,14,17].…”

Heat- and corrosion-resistant catalytic materials for environmental and energy applications

“…15) Additionally, the Rh/AlPO 4 catalyst exhibits a much higher resistance to sulfur and phosphorus poisoning compared with Rh/£-Al 2 O 3 . 18)…”

Hydrotreating Activity of Co-Mo/Al2O3 Promoted with Boron and Phosphorous

“…1). The reducible catalyst was due to the strong interaction between cobalt with aluminum phase, and because of the formation of AlPO 4 on the surface of support [21].…”

“…The addition of phosphate led to formation of AlPO 4 on the Al 2 O 3 support which decrease the surface area and pore volume of the support [21]. Phosphate is as AlPO 4 strongly bound to the Al 2 O 3 surface and thereby changes also the concentration of the acid sites and their acid strength, an important parameter with respect to the cracking and hydrogenation activity, as well as to the coke formation.…”