EXAFS measurement with laboratory equipment: Problems and their countermeasures

Experimental techniques for eliminating the characteristic x‐rays emitted from impurities in cathode and anode materials in the vicinity of the x‐ray absorption edge were studied with a laboratory EXAFS spectrometer using a rotating anode. Two methods are proposed for this purpose, a current‐control system and a filter method involving the use of a material that selectively absorbs characteristic x‐rays. The former method was applied to the Co, Ni and Zn K absorption spectra and the latter to a Pd K absorption spectrum, and the results were compared with those obtained from conventional measurements. The change in the nearest neighbour structure of Pd in a Pd‐Al2O3 catalyst accompanied by oxidation or reduction was clarified by EXAFS and XANES measurements with the use of the filter method.