A nanoporous silver (np-Ag) catalyst has been developed as a selective and efficient electrocatalyst for the reduction of carbon dioxide (CO₂) to carbon monoxide (CO). This catalyst exhibits significantly higher activity compared to traditional polycrystalline silver, achieving approximately 92% selectivity at a current density 3,000 times higher under moderate overpotentials of less than 0.50 V. The enhanced performance is attributed to a large electrochemical surface area (150 times larger) and intrinsic activity (20 times higher) due to the highly curved internal surface, which stabilizes CO₂⁻ intermediates and reduces overpotentials. The np-Ag catalyst also demonstrates exceptional stability, maintaining a CO Faradaic efficiency of over 87% during prolonged electrolysis. The np-Ag catalyst was synthesized through a two-step dealloying process, resulting in a three-dimensional nanoporous structure with a high crystallinity. Electrochemical tests showed that np-Ag outperformed polycrystalline silver and other silver nanostructures in CO₂ reduction, with a Tafel slope of 58 mV dec⁻¹, indicating faster electron transfer and better intrinsic activity. The catalyst's performance was further supported by detailed electrochemical and structural analyses, revealing its high surface area and efficient surface site activity. The np-Ag catalyst's advantages include its high activity, selectivity, and stability, making it a promising candidate for CO₂ reduction in aqueous electrolytes. It offers a cost-effective and sustainable solution for converting CO₂ into valuable chemicals, contributing to renewable energy and reducing greenhouse gas emissions. The study highlights the potential of nanoporous materials in electrocatalysis and underscores the importance of surface engineering for enhancing catalytic performance.A nanoporous silver (np-Ag) catalyst has been developed as a selective and efficient electrocatalyst for the reduction of carbon dioxide (CO₂) to carbon monoxide (CO). This catalyst exhibits significantly higher activity compared to traditional polycrystalline silver, achieving approximately 92% selectivity at a current density 3,000 times higher under moderate overpotentials of less than 0.50 V. The enhanced performance is attributed to a large electrochemical surface area (150 times larger) and intrinsic activity (20 times higher) due to the highly curved internal surface, which stabilizes CO₂⁻ intermediates and reduces overpotentials. The np-Ag catalyst also demonstrates exceptional stability, maintaining a CO Faradaic efficiency of over 87% during prolonged electrolysis. The np-Ag catalyst was synthesized through a two-step dealloying process, resulting in a three-dimensional nanoporous structure with a high crystallinity. Electrochemical tests showed that np-Ag outperformed polycrystalline silver and other silver nanostructures in CO₂ reduction, with a Tafel slope of 58 mV dec⁻¹, indicating faster electron transfer and better intrinsic activity. The catalyst's performance was further supported by detailed electrochemical and structural analyses, revealing its high surface area and efficient surface site activity. The np-Ag catalyst's advantages include its high activity, selectivity, and stability, making it a promising candidate for CO₂ reduction in aqueous electrolytes. It offers a cost-effective and sustainable solution for converting CO₂ into valuable chemicals, contributing to renewable energy and reducing greenhouse gas emissions. The study highlights the potential of nanoporous materials in electrocatalysis and underscores the importance of surface engineering for enhancing catalytic performance.