Fig. 5: The fitting results of the experimental XAS with background fitting.

The fitting results of the experimental XAS spectrum with background fitting for different sampling points: a 17 sampling points (Step 5); b 24 sampling points (Step 12); c 32 sampling points (Step 20); d the convergence of the fitted XAS curve in comparison to the experimental curve, with the colored dots denoting in order the results of Fig. 5a–c.