To address this gap, this study employs a novel surface modification strategy using SnCl4 as a Lewis acid to enhance the ECR performance of Cu2O. Unlike previous studies that introduce halide-based salts into the electrolyte to investigate halide adsorption effects, this work directly anchors SnCl4 onto the electrode surface rather than relying on dissolved Cl -ions. This approach ensures controlled and localized chloride adsorption, avoiding the fluctuations in Cl - concentration associated with electrolyte-based methods, which can lead to uncontrolled adsorption-desorption behavior, unpredictable competitive interactions with reaction intermediates, and potential electrode degradation. By modifying Cu2O with SnCl4, chloride ions are directly bound to the catalyst surface, providing a stable and reproducible environment for systematically investigating their role in CO2 reduction. This method allows for a more precise understanding of the impact of chloride species on catalytic performance, particularly in steering the reaction pathway toward ethane formation.