Fig. 5: Investigation of reactants and microenvironment evolution.

a Electrochemical in situ ATR − FTIR spectra of the Sn catalyst during the electrosynthesis of Gly. The electrochemical test potential ranged from 0 V to −1.6 V vs. SHE. The electrolyte was 5 mL of 0.5 M HNO₃ + 0.5 M OA. b Time-resolved electrochemical in situ ATR − FTIR spectra for synthetic Gly at −1.4 V vs. SHE, and the interval of the spectra is 1 min. c LSV curves of the Pt-ring in a 0.5 M HNO₃ + 0.5 M OA mixed solution with different volumes of 5 M KOH added. The disk electrode consists of Sn nanoparticles loaded on a glassy carbon electrode, and the disk potential is −1.4 V vs. SHE. d Local pH on the catalyst surface in different bulk pH electrolyte. e In situ EQCM test for mass changes (Δm) at –1.4 V vs. SHE in 0.5 M OA, GOA and GAO, respectively. H₂SO₄ (0.25 M) was added to the initial solution such that the H⁺ concentration was the same as that in the reaction environment. During the test, 5 M KOH was used to adjust the pH. f Adsorption energy of optimized geometries of molecules on amorphous Sn surface. The inserted images show the corresponding adsorption geometries on amorphous Sn. Source data for Fig. 5 are provided as a Source Data file.