Tin (Sn) and its alloys are widely used as electrodes for electrochemical CO2 reduction (EC CO2R) due to their unique p-block elemental character. In this study, we investigated the performance of Sn and Sn alloys (SnBi and SnPb) electrodes for EC CO2R under various conditions. The elemental distributions of the electrodes were examined using depth-profiling X-ray photoelectron spectroscopy (XPS) before and after EC CO2R. Our results demonstrate that Sn and its alloys can efficiently produce formate/formic acid with high Faradaic efficiency and selectivity. The Faradaic efficiency was found to be 96%, 93%, and 92% for Sn, SnBi, and SnPb electrodes, respectively, with a significant increase in formate selectivity to 99.7%. The depth profiling XPS analysis revealed substantial changes in elemental distribution, oxidation state, and oxide layer thickness after EC CO2R. Additionally, the elemental composition was found to vary with depth. The newly revealed surface elemental composition with depth and the EC CO2R performance provide valuable insights into the interfacial electronic structure of the electrodes before and after EC CO2R. These findings are crucial for developing more realistic theoretical models of the electrode and optimizing the electrochemical process for practical applications.