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

Progress in the development of CO2 reductioncatalysts has revealed more stable and selective options for solarfuel production. In most cases, the catalysts are tested under steady-state conditions. However, to become a reliable long-term storagesolution for renewable energy, particularly photovoltaics (PV), CO2electroreduction must tolerate power intermittency. Directcoupling of CO2 electrolyzers to PV devices enables carbonutilization and efficient energy storage but requires catalysts thatmaintain consistent performance under dynamic power input.Herein, we select an Ag nanoparticle gas diffusion cathode withstable CO production across a wide current density range. Thesystem, directly coupled to a hardware-emulated Si-PV moduleoperating 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, therebyadvancing practical implementation of solar-driven CO2 reduction.