Persistent CO ₂ Reduction Performance of an Ag Nanoparticle Gas Diffusion Electrode in Realistic Dynamic PV-Driven Operation

Progress in the development of CO₂ reduction catalysts has revealed more stable and selective options for solar fuel production. In most cases, the catalysts are tested under steady-state conditions. However, to become a reliable long-term storage solution for renewable energy, particularly photovoltaics (PV), CO₂ electroreduction must tolerate power intermittency. Direct coupling of CO₂ electrolyzers to PV devices enables carbon utilization and efficient energy storage but requires catalysts that maintain consistent performance under dynamic power input. Herein, we select an Ag nanoparticle gas diffusion cathode with stable CO production across a wide current density range. The system, directly coupled to a hardware-emulated Si-PV module operating under a realistic sunny day profile, achieves 96% energy coupling efficiency and reaches a cumulative solar-to-chemical (CO) efficiency of 8.8% in 1 day. This study demonstrates the potential of Ag-based cathodes for robust performance in variable PV-powered systems and introduces a novel test methodology that better reflects real-world PV-electrolyzer integration, thereby advancing practical implementation of solar-driven CO₂ reduction.