Complementary to conventional X-ray absorption near edge structure (XANES) and Fourier transformed (FT) extended X-ray absorption fine structure (EXAFS) analysis, the systematic application of wavelet transformed (WT) XAS is shown to disclose the physico-chemical mechanisms governing Pt-In catalyst formation. The simultaneous k- and R-space resolution of the WT XAS signal allows for the efficient allocation of the elemental nature to each R-space peak. Because of its elemental discrimination capacity, the technique delivers structural models which can subsequently serve as an input for quantitative FT EXAFS modelling. The advantages and limitations of applying WT XAS are demonstrated (1) before and (2) after calcination to 650 °C of a Pt(acac)2 impregnated Mg(In)(Al)Ox support, and (3) after subsequent H2 reduction to 650 °C. Combined XANES, FT and WT XAS analysis shows that the acac ligands of the Pt precursor decompose during calcination, leading to atomically dispersed Pt4+ cations on the Mg(In)(Al)Ox support. H2 reduction treatment eventually results in the formation of 1.5 nm Pt-In alloyed nanoparticles. Wide-spread use and systematic application of wavelet-based XAS can potentially reveal in greater details the intricate mechanisms involved in catalysis, chemistry and related fields.