**1. FT-IR**

FT-IR spectra were recorded on an FT-IR Tensor 27 spectrometer (Bruker) using ATR.

Figure S1 displays the FT-IR spectrum of carboxylated WS2 INTs with peaks of interest marked. The peaks can be assigned as follows (wavenumbers Q in cm<sup>í</sup><sup>1</sup> ). 3367, O-H stretch; 2881, C-H stretch; 1747, C=O stretch of carboxylic acid; 1467, C-H bend; 1360, C-H rock; 1039, C=S stretch (indicative of covalent attachment to sulfur of the INTs); 946, O-H of carboxylic acid.

**Figure S1.** FT-IR spectrum of carboxylated WS2 INTs.
