NO Reduction by CH_4 Over Well-Structured Pt Nanocrystals Supported on γ-Al_2O_3

摘要

Platinum nanocrystals, with an average diameter of 12 nm, were prepared by the reduction of K_2PtCl_4 with H_2 in the presence of the polymer of N-isopropylacrylamide. The Pt nanocrystals, having mainly cubic shape (≈ 64%), were supported on γ-Al_2O_3 and then tested for NO/CH_4 reaction. In contrast to the conventional Pt/γ-Al_2O_3 catalyst, the formation of NH_3 and CO as side products was not evidenced below 600 °C for Pt nanocrystals supported on alumina [Pt(100)/Al_2O_3]. On the other hand, higher yield to N_2O was observed for Pt(100)/Al_2O_3 as compared with the conventional catalyst. Both, the size and dominant crystallographic orientation of the supported Pt particles have been found to be important factors for the catalyst activity for NO/CH_4 reaction.