Catalytic Degradation of Polystyrene at Low Temperature over a Mo–W–Fe–Ni Carbide–Alloy Catalyst

<b>1) </b>This Supplementary Material accompanies the article <i>“Catalytic Degradation of Polystyrene at Low Temperature over a Mo–W–Fe–Ni Carbide–Alloy Catalyst.”</i> It provides additional methodological details and numerical data for the analysis of styrene oligomer distributions obtained by ESI mass spectrometry.Section S1 describes how MS-based number- and weight-average degrees of polymerisation (DP_n, DP_w) and the corresponding apparent molar-mass averages (M_n^{MS}, M_w^{MS}) were calculated from the resolved [C_8H_8]_n[C\_8H\_8]\_n[C_8H_8]_n series, using normalised peak intensities as semi-quantitative measures of oligomer abundance. Table S1 reports these values for the blank and the three catalytic runs at 90, 100 and 110 °C, including dispersity (PDI) and the fraction of MS intensity associated with short chains (n ≤ 15).Section S2 briefly discusses minor, low-intensity peaks that cannot be assigned unambiguously within the simple [C_8H_8]_n[C\_8H\_8]\_n[C_8H_8]_n + single-end-group model, explaining why they are excluded from the MS-based averages and why they do not affect the mechanistic conclusions of the main paper. <br><b>2) DRX RAW DATA of the catalysts </b>