Somasundaram Subramanian

Composition of Pd-La/α-Al2O3 catalysts

The objective of this study is to investigate the structure of the Pd-La/α-Al2O3 catalyst. X-ray diffraction (XRD) and temperature-programmed reduction (TPRd) were used as characterization techniques. Contrary to the assertions in the literature, XRD studies conducted on La/α-Al2O3 composite oxides and Pd-La/α-Al2O3 catalysts show that Pd catalyzes the solid state reaction between A12O3 and Al2O3 to form LaAlO3. TPRd studies conducted on Pd/α-Al2O3, Pd/La2O3, Pd/LaAlO3, and Pd-La/α-Al2O3 catalysts suggest that Pd in the Pd-La/α-Al2O3 catalyst interacts more strongly with LaAlO3 than with α-Al2O3. Reaction studies were conducted to investigate the activity of Pd/α-Al2O3, Pd/La2O3, Pd/LaA103, and Pd-La/α-Al2O3 catalysts for nitric oxide (NO) reduction. These studies show that Pd/LaAlO3 catalysts are most active for NO removal at stoichiometric and under net reducing conditions.