Fig. 4: Exploration of active sites. | Nature Communications

Fig. 4: Exploration of active sites.

From: Sn catalyst reconstruction and microenvironment modulation for efficient amino acid electrosynthesis via C–N coupling

Fig. 4: Exploration of active sites.The alternative text for this image may have been generated using AI.

a In situ XRD patterns of the Sn catalysts during the electrosynthesis of Gly. The black curve was obtained without an applied potential, and the blue curves were obtained at −1.4 V vs. SHE. and b In situ Raman tests of the Sn catalysts during the electrosynthesis of Gly. The experimental potential ranges from 0 V to −1.8 V vs. SHE. c Intermittent in situ Raman tests with alternating conditions at a turn-on (−1.4 V vs. SHE) and a turn-off voltage. d Intermittent in situ DEMS measurement in alternating 0.5 M HNO3 and 0.25 M H2SO4 electrolytes. The initial electrolyte tested was 0.25 M H2SO4. The dashed lines and arrows indicate the switching of electrolytes. The red area represents 0.25 M H2SO4 at −1.4 V vs. RHE. The blue area represents 0.5 M HNO3 without any potential. e In situ XANES data at different potentials. The gray line represents the test curve obtained in air. The blue lines represent the test curve obtained in the mixed electrolyte (0.5 M HNO3 + 0.5 M OA) at −0.3 V vs. SHE. The red lines represent the test curve obtained in the mixed electrolyte (0.5 M HNO3 + 0.5 M OA) at −1.4 V vs. SHE. f In situ valence analysis of Sn based on linear combination analysis of in situ XANES data. The blue and red areas correspond to the blue and red curves in Fig. 4d, respectively. g Bode plots for Sn nanoparticles with different amorphous ratios. The amorphous ratio is regulated by the different reaction times of the crystalline Sn nanoparticles in the mixed electrolyte. h In situ EQCM test for mass changes (Δm) in crystalline and amorphous Sn at different potentials. Figure 4h shows a summary of the maximum Δm. The electrolyte was a 0.5 M solution of the corresponding tested chemicals. The potential range is −0.4 V to –1.6 V vs. SHE. Amorphous Sn was obtained after electroactivation for 30 min in the mixed electrolyte over crystalline Sn at –1.4 V vs. SHE. i Calculated Bader charges δ on top layers (range of the red dotted box) for amorphous and crystallized Sn (101), with O, Sn and H are shown with red, dark gray and white balls. Source data for Fig. 4 are provided as a Source Data file.

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