Development of Hexaaluminogallate/ Solid Electrolyte Laminated System for NO_x Reduction

Abstract

Hexaaluminogallate/ oxide ion conductive electrolyte laminated system has been developed as the direct NO_x reduction system without any reductant gases.Hexaaluminogallate compound (Ba(Al,Ga)₁₂O₁₉) has high melting point and tends to grow as characteristic plate-like particles. In addition, the Al/Ga lattice sites in their structures can be substituted for various metals.The authors have found that hexaaluminogallate powders synthesized by coprecipitation method had high catalytic activity of NO_x reduction in NO/ O₂/ C₃H₆ reaction. In this study, the electrical and catalytic properties of the novel ceramic catalyst system with a stacked structure between hexaaluminogallate and electrolyte were investigated.In this system, oxygen adsorbed on the active sites, which is one of the causes of degradation of catalytic activity, could be removed by transporting oxide ions through electrolyte phase, leading to the improvement of direct NO_x reduction without any reductant gases.