The acidity of Al1-O3H-Si4 and Al4-O3H-Si1 is equivalent, Al3-O11H-Si2 and Al8-O10-Si2 sites are less and higher than the first two Br? ?nsted acid sites, respectively.

• Al1-O3H-Si4和Al4-O3H-Si1位的酸性强度接近,Al3-O11H-Si2和Al8-O10H-Si2位的酸性分别略低于和略高于前两个酸位。