Na K-edge XAFS Study of Sodium Loaded on Alumina

Na K-edge XAFS of Na 2 O/Al 2 O 3 catalysts(4-32 wt% Na) was examined. It was deduced on the basis of XANES of sodium halides that the ionicity of an Na-O bond in catalyst sample relates to the energy position of the prominent peak at Na K-edge, which is consistent with the catalytic performance. The amount of species with the moietiy of Na-O-Al increases with an increase in Na loading up to 16 wt%. The Na-O-Na structure begins to grow from 16 wt % loading. The surface oxygen in Na-O-Al is concluded to be active species.