Generation and catalysis of Bronsted acid site on the surface of ceramics

高温焙烧的Nb_2O_5/Al_2O_3和Ta_2O_5/Al_2O_3催化剂表现出Bronsted酸性质。在高温焙烧的Nb_2O_5/Al_2O_3和Ta_2O_5/Al_2O_3催化剂上稳定了单层具有扭曲八面体对称性的铌酸和类钽酸化合物。稳定的铌酸和类钽酸化合物的二维Nb-O-Nb网络和Ta-O-Ta网络解释了Bronsted酸中心的产生。

Nb_2O_5/Al_2O_3 and Ta_2O_5/Al_2O_3 catalysts calcined at high temperatures exhibited the Bronsted acid property. A monolayer of niobic acid- and tantalum acid-like compounds, which have distorted octahedral symmetry, was stabilized over Nb_2O_5/Al_2O_3 and Ta_2O_5/Al_2O_3 catalysts calcined at high temperatures. The two-dimensional Nb-O-Nb network and Ta-O-Ta network of stabilized niobic acid- and tantalum acid-like compounds account for the generation of Bronsted acid sites.